dec 2007 regist€red with registrar of ncws paper · depression and its relation to coronary...
TRANSCRIPT
Dec 2007 Regist€red with Registrar of ncws paperfor India Reg. No. 69E28199
*
MARINE MEDICAL SOCIETY(Regd F-3611)
PresidentSurg V Adm Sujan Singh PHS
Vice PresidentsSurg R Adm VS Dixit VSM
Surg R Adm SK Moharity SM VSM
Executive Commi.ttee
Surg Cmde MJ John Surg Cmde KB Misra
Surg Cmde SR Gedela Surg Cmde YP Monga NM
Surg Cmde S Kumar VSM Surg Capt S Nangpal
Surg Capt B Sudarsan Surg Capt G Verghese
SecretarySurg Cdr Al Ahmed
TreasurerSurg Cdr P Ramesh
Addre ss for Corre spondenceSecretary
Marine Medical SocietyINHSAsvini
Colaba, Mumbai 400005. IndiaWebsite : http://www.mmsindia.net
I
JOURNAL OF
MARINEMEDICALSOCIETY
Published Biannuallv
Editor-in-ChiefSurg R Adm VS Dixit VSM
EditorSurg Capt AA Pawar
Addre s s fo r C orre sp ondenc eSecretary
MarineMedical SocietyINHS Asvini
Colaba, Mumbai 400 005.IndiaWebsite : http ://www.mmsindi a.net
Printed, published and ownedby DirectorGeneral of Medical Services (Navy), SenaBhavan, New Delhi 110 0l l. Printed on his behalf atTypo Graphics, Mumbai 400 103.
of
I S
to
n
!
t
t s!S
JOT]RNAL OF MARIIYE MEDICAL SOCIETY
- CONTENTS
Editodal
Does Navy Need to Invest in the Maniage of its Personnel?Surg Capt AA Pawar
ORIGINALARTICI-ES
Design and Development of Suhmarine Escape Set Test FacilitiesGSN Murty, YS Prakash, Arun Kumar, Dr VC Padaki
Indigenous Development of the Submarine Escape Set IDA 59-MSurg Cdr CS Saxena, Surg Cdr PP Bellubbi VSM (Retd), Arun Kumar
SubmarineAtmosphere Regeneration System: Present Scenario and Future TrendSurg Commander DK Ghosh
SMERG (2003-07) - Joint Effort' For Rescue of Personnel from a Disabled SubmarineSurg Cdr GD Bhanot
Present Day Concepts in Management of cranio maxillofacial trauma 106Surg Cmde (D) Sushanta Karkun, Surg Lt Cdr (D) K Majumder
Depression and Its Relation to Coronary Artery Disease ll2Surg Cdr A Tripathi, Surg Capt M Pawar Ms P Kalyankar Surg Cdr NK Mahesh,Surg Cdr KK Mishra, Ms J Rathod
Optimizing Glycemic Control and Achieving Glycemic Targets in anArmed Forces Setup 116Surg Cdr Vvek Kumar Surg Capt Ashok Bhagra
Body Mass Index and Obesity : Tailor Making Cut-offfor our Population l2ILt CoI SP Singh, Surg Lt Cdr Gaurav Sikri, Lt Col MK Garg
Rugged, Portable Biomedical Data Acquisition and Transmission System -Telemedicine System forArmedForces
SR Sumathi, DT Shakunthala, PS Pandian, Uma U Maheshwari, Mohan K Velu, Anuradha Srinivas,KP Safeea Madhabi Sarkar Deepa Prabhu, SG Gruruprasad, PM Saga4 Jyotsna Shahpurka4Dr BS Surdersheshu, Dr VC Padki
Aircrew Fatigue : The Hidden Danger
Surg Cdr RC Verma
CASEREFORTS
A Case of Sea Sickness in a Naval HelicopterPilot
Surg Cdr S Patnaik, Surg Cdr RK Verma
ComprehensiveNeuro Ct Imaging inAcute Stroke: What's New?Pradipta C Hande
Jour Marine Medical Society, 2N7, Vol.9, No.2
Ia
tE
,i
D
m
86
91
s
126
t32
135
r39 F,78
DESIGN AND DEVELOPMENT OF SUBMARINE ESCAPE SET TESTFACILITIES
GSN Murty, YS Prakash, A run Kumar, Dr VC Padaki---
ABSTRACT
Submarine Escape Set (SES) is used by submariners to escape from a sunken submarine. This set caters forbreathing needs of the submariner under water, until he reaches the surface. Evaluation of such life savingequipment is of paramount importance. lndigenous test faci l i t ies which can evaluate the SES have beendescribed in this paper. Thls paper also brief ly describes the submarine escape set and deals with variousconstructional features and schedules of operation of test facilities. The total test facility is divided into twoparts l) The reducer test faci l i ty and 2) The breathing bag test faci l i ty. The equipment has been r igorouslytested and accepted by Indian Navy. Two such test facilities have been developed, one of which is installed at INSSatavahana, Visakhapatnam and are working satisfactori ly t i l l date.
Key Words : PKY Testen KG Chamber, Hypoxia, Depth compensator, Thermal mass flow meters
a
$€
INTRODUCTION
Q ubmarine Escape Set (Fig. I ) is used ro save theLJlife of submariners in the event they have toabandon the submarine and save their life. Thisequipment basically consists of a Hydro Suit and aBreathing Bag. The Hydrosuit protects the wearerfrom hypothermia [] and reptile bites and also im-parts vertical posture during ascent with the help ofmetal soles in the boots. It also has a facility to keepthe escapee in supine position by the use of fingerbottles provided in the thigh region. Breathing bag(Fig. 2) is an annulus rubber bag worn round theneck and connected to the hydrosuit breathing tractat mouth with swivel arrangement. The Breathingbag caters for the breathing needs of the subma-riner throughout the ascent duration. This bag isfitted with various valves like demand valve, pres-sure release safety valve, valve box, canister, oxygenand mixture reducers fitted on to the bottles. Breath-ing bag provides breath ing gases of vary ingcomposition depending on the depth with the helpof mixture and oxygen reducers. The set is meant forsaving from depths up to 100 m. While escapingfrom submarine initially the mixture cylinder fittedwith depth compensated reducer and the demandvalve provide the requisite gas mixture for breath-
Fig. I : Submarine escape set.
ing on demand up to a depth of 68 m. Between 68-45m depth oxygen cylinder fitted with hermetically
t
_?
)
Defence Bio-Engineering and Electromedical Laboratory, Bangalore 560093. "'scientist D
80 Jour. Marine Medical Society, 2007, Vol.9, No.2
5
r|t
Fig.2 : Breathing apparatus.
sealed reducer starts to provide oxygen at presetrates (Table l) independent of demand up to sur-face. I t is of paramount importance that thecomponents should be periodically evaluated fortheir functional intactness without actually puttingthe equipment into the water. The present test facili-ties are designed to meet the test schedules laiddown for the Submarine Escape Set.
TABLE IReducer test facility test schedule (Depth chart)
Constant flow rate of oxygen fed by the reducer and thechangeover valve at varying depths:(a) During Descent (surrounding pressureincreases)
Depth o f 0 24 37 68 100Submergence(in mtr)
Pressure in O 2.4 3.7 6.8 I 0chamber (Kg/cm'z)
O x y g e n f l o w 0 . 3 - 0 . 6 0 2 . - 0 . 6 0 . 5 - l . l 0 0( l i t /m in)
(b) During Ascent (surrounding pressuredec reases )
Depth of 68
Submergence
( in mtr)
Pressure in 6.8
chamber (Kg/cm'?)
Oxygen flow 0
rate ( l i t /min)
Jour. Marine Medical Society, 2007, Vol.9, No.2
DESCRIPTION
Fig. 3 shows the test facilities developed initiallyas MK I which is in use at DEBEL. Fig. 4 shows theimproved version of the test facilities (MK-II) whichhas been further modified and supplied to Navy.The concept of modularity and ease of operationare maintained in both facilities which are in workingcondition till date. The test facilities are divided intotwo parts 'Reducer Test Facility' and 'Breathing BagTest facility'.
Reducer test facility
In case less oxygen is supplied to the submarinerit causes hypoxia [2] and if excess of oxygen issupplied it causes oxygen poisoning [3]. So it isvery essential to provide the submariners with exact
Fig. 3 : Reducer and breathing bag test facility MK-I.
^ <
2 . O
3.0-4 .4
0
3 . Z - 4 . 4
4 . 5
0 - l . lFig. 4 : Reducer and breathing bag test facility MK
(installed at INS Satavahana).
B.aih,na g.r Ic$ frcilkt
81
rated flows of oxygen during escape. Keeping thisin mind a test facility was designed to meter thecorrect quantity of oxygen delivered into the bag.This facility is named as 'ReducerTest Facility'. Thistest facility basically consists of a Pressurizationvessel, Depth compensator, Air mix clipper, BreathingBag simulator NRV Thermal mass flow meter to meterthe flows, and a digital read out connected to threepressure sensors through a selector switch. ThreeSensors viz., Sensor I to view the vessel pressure,Sensor 2 to view Low pressure (LP) setting of thereducer, Sensor 3 to view the pressure in the depthcompensator, are connected as shown in Fig. 5. Thesource of perssurized air is from compressor. Theoxygen cylinder fitted with reducer is pressurized inthe piessurization vessel upto l0 kgf/cm2. Theconnection details of the circuit are also shown inFig. 5. The cylinder to be tested is kept inside thechamber in spindle open condition and the chamberis pressurized gradually in steps. This is equivalentto actually testing the reducer at those depth insidethe sea. Readings are to be noted at the specifieddepth as shown in Table l.
Breathing bag test facility
This facility is designed to test pressure releasesafety valve (PRSV), Automatic Demand Valve(ADV), valve box, canister, reducer safety valves ofoxygen and mixture reducers, and hydrosuit. Thetest facility is designed in modular concept whereineach test is performed by pre-established testcircuits marked with the test name. Separate fixingadapter with swivel mechanism with shutoff valvesare provided for quick connection and disconnection
of test circuit. The modular concept uses separatededicated sensor and indicators for each test whichdispenses the interchange ofconnections and helpsin easy t rouble shoot ing and replacement ofcomponents. Turbine flow meters, [4] thermal massflow meters [5] were used in conjunction with digitalpressure indicators and d ia l pressure gauges.Hydrosuit inflation and pressure holding test isprovided with dial pressure gauge with press tomeasure facility to avoid eventual excess pressurebeing applied to the gauge. This facility can test at atime five breathing bags for various components ininsitu conditibn (without dismantling from the bag).This facility is of great use when large quantity ofbags are to be tested. The accuracy of digital flowmeters and pressure indicators eliminates observererrors. This facility uses compressor and dispensesthe storage of big cylinders at high pressures. Morethan 500 sets have been so far tested on the testf ac i l i t y es tab l i shed a t INS Sa tavahana ,Visakhapatnam.
DESIGN CONSIDERATIONS
Both reducer and breathing bag test facilities aredesigned to be stand alone. Single compressor drivesboth the facilities at a time. All test circuits are pre-laid, no inter change of connections or devices arerequired unlike in PKY tester or KG chamber. Thisreduces the testing time and test preparation timedrastically. Safety valves are provided in the circuitryfor pressure vessel to vent out eventual excesspressure. All circuitry materials are indigenous.Stainless Steel is chosen for pressure vessel and forall internal piping to make the system corrosionresistant. A user handbook has been provided whichgives description of initial checks to find out theserviceability of each circuit. Digital displays add tothe case of reading. Three position selector switchis provided for ready noting ofreadings and also tod iagnose whe the r t he dep th compensa to r i sfunctioning normally or otherwise (the readings inposition I should be less than position 3 for flow tooccur). Thermal mass flow meters known for theiraccuracy and repeatability have been used.
OPERATION OF REDUCER TEST FACTLITY
The oxygen cylinder fitted with reducer andcharged to 200 bar is connected as shown in the Fig.
Jour Marine Medical Societv,2007, VoL9, No.2
Fig. 5 : Schematic layout of reducer test facility.
82
Fig. 6 : Schematic of breathing bag test facility.
5. The lid is closed and the pressurization valve isoperated slowly in steps as per the depth chart fordescent. The pressurization valve is closed and thevent valve is gradually opened to note ascent values.The readings are noted down at each depth and arecompared with the admissible values. Detailedprocedures are provided in the user handbooksavailable at Navy and DEBEL.
OPERATION OF BREATHING BAG TESTFACILITY
Fig. 6 gives a schematic idea of the test facilitywith various perset lines like pressure release safetyvalve, demand valve, valve box, canister, reducersafety valve and hydro suit. To conduct the test therequired test line is chosen and the breathing bag isconnected to the swivel connector at mouth pieceby hand tightening the threads and the shutoff isopened to note down the readings of pressure/flowindicator as each test line is preset for the test. Theshut off valve is closed after the test is completedand the breathing bag is disconnected from theswivel connector. Detailed procedures are given inthe user handbooks available at Navv and DEBEL.The tests are s impl i f ied i ry prov id ing presetparameter lines. For testing hydrosuit the mouthpiece union is connected to the adaptor providedand the flutter valves and bib are tied and the headequalizing valve is closed and slowly pressurizedupto 200 mm water column in steps and the gaugelock switch is pressed to see the reading. Thispressure should hold for 5 minutes time without anydrop. Similarly inflation compartments can also betested.
Jour Marine Medical Society, 2007, VoL9, No.2
DISCUSSION
The results obtained with standard sets broughtfrom INS Virbahu/Vajrabahu on KG chamber and PKYtester are in close agreement with the values obtainedwith reducer and breathing bag test facil i tresrespect ive ly and conf i rms the accuracy andrepeatability of tests being performed (Tables 2 to5). Also this test facil i ty has the advantage ofsimultaneous testing of f ive breathing bags inbreathing bag test facility and the time taken foreach test is much lesser. Satisfactorv certificate of
TABLE 2Test schedule prescribed for breathing bag testfacil i ty
I Resistance of breathing apparatus should be from
105 to 170 mm Hzo at a suct ion of 501 pm
2 Demand valve flow should be more than 401 pm
3. Resistance of safety valve of breathing bag for a
flow of-31 pm should be from 200 to 450 mm H2o
when adapter nut is unscrewed completely
4 Resistance of safety valve of breathing bag for a
flow of 3l pm should be from 50 to 100 mm Hzo
when adapter nut is unscrewed completely
5 Internal regenerative canister is considered tight if
height of liquid level in manometer of 100 mm H,O
and does not vary for one min.
6 No bubbles should come from the canister when
dipped in water with a pressure of 1200-1300 mm
H2o for external tightness.
7 Safety valve of oxygen reducer should open between
9 to 16 kg/cm2
8 Safety valve of mixture reducer should open
between 12.5 to 19 kg/cm'?
9 Valve box mica exhalation and inhalation valves are
gas tight if the leak is below 0.551 pm to 200 mm
HrO pressure
l 1
Pressure at outlet should be from 5.5 to 6.5 kg/cm?
for oxygen reducer and 5.3 to 6.6 kg/cm? for
mixture reducer when pressure in cylinder is 180-
22O kglcm2
Resistance of apparatus should be exceed 25 mm
HrO to a flow of 301 pm with uncharged canister
Hydro suit will be inflated to a pressure of 200 mm
mm HrO after tying the bib portion of the hydro
suit. The hydro suit is tested for any leaks by
applying soap solution on the surface. Also there
should not be any pressure drop within 5 minutes
l 0
t 2
8.t
TABLE3 TABLE4
Reducer test facility (MK.I) performance Reducer test facility (MK.II) performancecomparison comparison
Depth Normal value Flow reading on Flow reading Depth Normal value Flow reading on Flow reading(Meter) of flow Certified Test on New Test (Meter) of flow Certified Test on New Test
( l i t /min) equipment equipment ( l i t /min) equipment equipment e(KG CHAMBER) (REDUCER (KG CHAMBER) (REDUCER
TESTFACILITY)
TESTFACILITY)
0 0.3-0.6 0.45 0.47 0 0.3-0.6 0.33 0.3224 0 .2 -0 .6 0 .40 0 .36 24 0 .2 -0 .6 0 .21 O .2437 l . l - 0 .5 1 .0 0 .90 30 0 .5 - l . l 0 .69 0 .706 8 0 0 0 3 7 l . l - 0 . 5 0 . 5 6 0 . 5 64s 0 - l . l 0 .6 0 .78 68 0 0 .0 0 .020 3-4.4 3. ' t 3 .86 45 0- l . l 0 .2 ' t 0 .220 3.2-4.4 3.8 3.94 20 3-4.4 2.84 2.80
0 3 . 2 - 4 . 4 2 . 8 6 2 . 8 4
TABLE 5
Breathing bag test facility (MK-I) performance comparison
Result on Result on NewCertified Test Test equipment
Sl. Name of the test equipment (BREATHINC BAG Normal ValueNo (PKY TESTER) TEST FACILITY)
I Check for canister for tightness No bubbling from No bubbling at the samecanister under pressure pressure and there was1200 mm HrO no drop of pressure
2 Gas tightness of Mica 0.40 lpm at 200 0.35 lpm at 200 Should not exceedinhalation valve mm of HrO mm of HrO 0.551 pm
3 Gas tightness of Mica 0.25 lpm at 200 0.35 lpm at 200 Should not exceedexhalation valve mm of HrO mm of HrO . 0.551 pm
4 Resistance of safety release 90 mm of H2O 88 mm of HrO 50-100 mm of HrOvalve (flow 3l pm)open position
5 Resistance of safety elease 300 mm of HrO 238 mm of HrO 200-450 mm of H2Ovalve (flow 3l pm)closed position
6 Automatic demand valve Opens at suction Opens at suction 105-170 mm ofopening pressure of 145 mm of HrO of 148 mm of H2O water column
7 Flow through Automatic 60 litres per 88 litre per minuet Should be >demand valve minute 40 lit/min
performancegivenbyNavyconfirrnsthattheutil i ty continuous use for the last three years. Oneand design meet the stated objectives. equipment stationed at INS Satavahana confirms . t
CONCLUSION the utility and design soundness. These are stepstowards indigenous development of facilities for
The test facil i t ies developed are under crit icaiNavalrequirements.
U Jour Marine Medical Society, 2007, Vol.9, No.2
TABLE 6
Breathing bag test facility (MK.I) performance comparison
Sl. Name of the test
N o
Result onCertified Testequipment(PKY TESTER)
Result on NewTest equipment(BREATHING
BAG TEST FACILITY)Normal Value
Check for canisterfor tightness
Gas tightness ofMica inhalation valVe
Gas tightness ofMica exhalation valve
Resistance ofSafety release valve(Flow 3 lpm)open position
Resistance ofsafety release valve(flow 3 lpm) closed position
Automatic demandvalve opening pressure
Flow throughAutomatic demand valve
No bubbling fromcanister under pressure1200 mm HrO
0.40 lpm at 200 mmof HrO
0.35 lpm at 200 mmHrO
80 mm of HrO
400 mm of HrO
Open at suction of 145mm of HrO
60 litre per minute
No bubbling at the samepressue and there was nodrop of pressure
0.40 lpm at 200 mmof HrO
0.40 lpm at 200 mmH20
70 mm of HrO
300 mm of HrO
Opens at suction of I38mm of HrO
88 litre per minute
Should not exceed0.55 lpm
Should notexceed 0.55 lpm
50-100 mm of HrO
200-450 mm of HrO
105-170 mm ofwater column
Should be> 40 litre/min
ACKNOWLEDGEMENTS
The cooperation and assistance given by the Trial teamof INS Satavahana and SMHQ Visakhapatanam during thedevelopment, trials and testing is gratefully acknowledged.
REFERENCES
l. Strauss RH. Diving Medicine. ln Grune and Strattoninc (Pub l isher ) 1976; sec 5 :2 l l -18 .
2. Guyton CA. Text Book of Medical Physiology. InIgaku-Shoin/Saunders. International Edition Medical
Jour. Marine Medical Society, 2N7, Vol.9, No.2
Physiology 1986;522.
Guyton CA. Text Book of Medical Physiology. lnIgaku-Shoin/Saunders International Edition MedicalPhysiology, 1986; 537-39.
Bela G Liptak (Editor in chief), Kristza Venczel(Associate Editor) Instrument Engineers Handbook -
In Chilton Book Company. 145-54.
Bela G Liptak (Editor in chief), Kristza VenczelInstrument Engineers Handbook - ln Chilton BookCompany 142-44.
5 .
85
INDIGENOUS DEVELOPMENT OF THE SUBMARINE ESCAPE SETIDA 59-M
Surg CdrCS Saxena., Surg CdrPPBellubbiVSM (Retd)",Arun Kumar***
ABSTRACT
Indian Navy inducted soviet origin submarines NATO designation'FOXTROT'in 1967. At the same t ime toprovide credible rescue and escape capabilities to distressed submarine, INS Nistar (SRV) and individual escapeapparatus consisting of ISP 60 and IDA 59 was also introduced. Over period of time a modified version ol ll),\ 59breathing apparatus was inducted in Indian Navy. However with breakdown of erstwhile USSR thc srrpply ofthis escape equipment became unrel iable and decision to indigenize this equipment by DRDO was taken.DEBEL, Bangalore was tasked with indigenizing this equipment and has successfully done so. User trials wereconducted on the indigenous submarine escape sets developed by DEBEL, as per test protocol approved by theSMHQ, The article is published to highlight some of the prollems and difficulties faced by the Project teamduring design and development and during the user tr ials. One such unresolved problem was the excessiveinflation of the breathing bag and positive buoyancy during ascent which could not be explained on the basis ofthe data collected on lhe consumption pattern of the diver during the ascent. This phenomenon was observedonly during the RCC simulated dive and during Tower escape and not during the swimming pool trials.
Key Words : Indigenisation of the submarine escape systems
INTRODUCTION
Q ubmarines unlike surface ships, by virtue of theUmedium that they operate in, are susceptible to adistinct set of problems which are quite differentfrom those experienced by surface ships. Any dis-aster occurring to a submarine at depth needs a welltrained and efficient organization geared up to meetthe various contingencies that are bound to comeup. This would be essential in order to prevent/re-duce the morbidity and mortality normally associatewith such events.
Escape and Rescue of personnel trapped in adistressed submarine is a complex and difficult task.Numerous factors have to be taken intoconsideration for a successful operation. Amongthe factors which have to be considered is theRescue Organization itself and the recommendationswhich are to be given to the personnel in distress.Rescue of the submarine along with its personnel,though feasible in most cases, may not be the bestoption. Hence more emphasis has been laid oncarrying out a successful individual Escape.
Shortage of spares and uncertain supply positionof IDA 59 M and lack of Quality control from theerstwhile USSR, there is a definite need to reviewthe Indigenizat ion ef for ts of th is l i fe savingequipment . The new Project envisages theproduction of a prototype Life support system forSubmariners with setting up of a local test Facilityand final user's trials at the Escape Training Schooland in actual submarine conditions.
After two initial futile attempts at indigenization,DEBEL has developed a modified version of theexisting self contained closed circuit breathingapparatus which is currently undergoing Useracceptance trails with the Navy. The indigenousbreathing set can be used for escape from the depthsrestricted to a maximum of 100 meters and up to 120meters with the diver supplied additional Heliumcylinder. IDA59 M set has already been indigenizedby DEBEL and feasibility studies carried out by thislaboratory have suggested that the Indigenoushydro suit can be modified to meet the requireddepths restrictions for escape from the disabled
'PMO INS Satavahana, Classified specialist in Marine Medicine; "Consultant Naval Projects DEBEL, Bangalore. l"Scientist
"C' DEBEL Bangalore.
Jour Marine Medical Society, 2007, VoL9, No. 286
submarine.
The prototype Breathing apparatuses andHydrosuit were subjected to extensive trials undersimulated conditions by the trained divers andqualified submariners. The article/paper pArpose tohighlight some of the problems and difficultiesencountered during the user trials and probablesolut ions to overcome these for successfu linduction for the use in the submarines.
Prototype Design and Development
The Naval Headquarters accorded an approvalto forward three sample sets of IDA 59 M and aHydrosuit for revival of the project.
After consultations with the specialists in thefield of rubber and coated fabrics, it was decided totry out nylon fabric coated with Hapalon andNeoprene and breathing bag and Hydrosuit. Thesefabrics were subjected to extensive laboratory andsimulated trials before fabrication of the bags adsuits. During the trials it was seen that there waswater seepage through the bib fabric and the rubbergloves were too fragile. Moreover the gloves didnot withstand the stipulated storage conditions. Thegloves melted under normal storage conditions.Hapalon coated fabric showed mottling during thenormal stowage conditions. Moreover the qualityassurance of fered by the vendor was notsatisfactory. It was therefore decided to change thevendor and a new vendor was ident i f ied fordesigning the rubber and fabric components ofthebreathing bag and the Hydrosuit.
New fabric coated with Neoprene/Flapalon wasdeveloped and was subjected to extensive laboratorytests. It was used in making the Breathing bag of theapparatus and Hydrosui t . Meta l componentsmanufactured by a different vendor were used forintegration of the breathing apparatus.
The assembled breath ing apparatuses andHydrosuit were subjected to extensive in-houselaboratory tests as per test protocol , on theindigenous test equipment developed by DEBEL,before actual user trials.
The results of in-house tests were within thenormal range as per approved test protocol andRussian BR. The results of the tests are placed atTable I and 2. Tr ia ls were conducted on 21
Jour. Marine Medical Society, 2007, VoL9, No. 2
June 2007.
Ibials of Indigenous Submarine Escape Sets
After repeated laboratory tests, the sets weresubjected to initial trials in the swimming pool andRCC from l6th to l9th January 2007. The setsperformed satisfactorily except for the water ingressin one of the sets which was found to be duemaladjustment of the ADV (Automatic DemandValve). The Hydrosuit material was causing somediscomfort due to its texture but there was no wateringress in both Zip type and Bib type Hydrosuit.However some divers expressed that the sets werenegatively buoyant during the ascent from 30 meters.Further trials were conducted in June 2007 with 5indigenous sets and one set wi th indigenousb rea th ing bag fab r i c w i t h me ta l l i c Russ iancomponents. Results of the trials are shown in theTables 4.5.6 and 7. Two indate Russian sets wereused for the trials for comparison and for acquiringaccurate data. All the sets were once again tested inthe test rig to synchronize the setting of Russianand indigenous sets. Though the Oxygen reducersettings of the Russian apparatuses were not in thestipulated range, it was decided that these sets willbe deployed for all the exercises.
During the testing of the assembled breathingapparatuses it was noticed that the indigenous setshowed more inflation than its Russian counterpart(See Figs. I and 2) and the bag appeared slightlybigger. Both the PRSVs were set to lift at identicalpressure.
During the swimming pool trials and escape towertrials all the divers and few trained submarinerscomplained of fullness of the breathing bag andinc reased pos i t i ve buoyancy du r i ng ascen t .However no diver or submariner complained of theincreased resistance to breathing. However duringthe escape tower trials, all the divers complained ofthe excessive inflated condition of the bag atshallower depths. Pre and post dive residual pressurein the Oxygen and Mixture bottles indicated thatthere was no difference in the consumption patternof the divers and submariners. Figs. 3 and 4 showsthe divers in the RCC exercises and swimming po.ol.Since there was no major malfunctioning of thecomponents of the sets, th is s t range inf la t ionphenomenon could not be explained on the basis of
87
Fig. I : Shows the inflated condition of the Russian originbag in SES test facility ashore.
Fig. I : Shows the inflated condition of the Russian origin Fig. 2 : Depicts inflation of the indigenous IDA 59 Mbag in SES test facility ashore. set.
TABLE I
Evaluations of indigenous (DEBEL) oxygen reducer feeder flow
Depth
(Meter)
Flowrange asper BR
Cylinder number
so3/06 so3/08 so3/09 so3/02
Cylinder HP 160 barReducer LP 5.8 bar
175 bar6.1 bar
160 bar5.7 bar
I 60 bar5.6 bar
160 bar 160 bar6.2 bar 6.3 bar
00245 t
6 8
4 5
2 0
0 0
0 .3 -0 .60 .2 -0 .60 . 5 - t . l
0 . 00 .0 - l . l3 .0-4.43 .2 -4 .4
0 .27o .250 .960 .00 .423 4 03 . 7 4
o.460 .321 . 0 80 .00 .573 .363.47
0.440 .320 .930 . 00.463 .9 84.02
0.400 .3 8l . t I0 . 00 .423.5 53.6 ' l
0 .36o .250 . 8 50 .00 .3 83 .653 .70
0 . 3 lo .230 .960 .00 . 5 03 . 8 23 .89
Evaluation of Russian oxyg€n reducer feeder flow
Cylinder No. N o . 4 l 3 0 No. 4702 No. 4842 No. 4294 No. 4316 N o . 4 l 3 0
Cylinder HPReducer LP
175 bar5.9 bar
150 bar6 .1 bar
I 80 bar5.6 bar
170 bar5.9 bar
t 70 bar5.9 bar
175 bar5.9 bar
0 0
24*
3 ' l * *
6 8
4 5
2 0
0 0
0 . 3 - 0 . 6
0 .2-0 .6
0 . 5 - l . l
0 . 0
0 . 0 - l . 1
3 .0-4 .4
3 . 2 - 4 . 4
0 . 3 - 0 . 6
0 . l 30.040 .700 .00.403 .7 83 . 8 00 . 1 3
o . 2 l0.090 .5 30 .00 .203 .673.'t 50 . 2 1
o .230 . l 00 .630 .0o .253 . 6 33 .66o .23
0 . t 30.050.5 ' l0 .00.053 . 3 0J . . ) J
0 . l 3
0 . l 9
0 . 0 7
0 . 6 6
0 . 0
0 . 1 8
3 . 8 0
3 . 8 6
0 . l 9
0 . r 30.040 .700 .00 .403 . 7 83 . 8 00 . 1 3
i,+*Indicate the flow at these depths is inadequate.
88 Jour Marine Medical Society,2007, Vol.9, No.2
TABLE2
Functional evaluation of indigenous breathing bag components
Description of Normal
Test as per BR Range
B B N o . I B B N o . 2 B B N O . 8 B B N o . 7 B B N o . 5 B B N o . 6O, Cyl No. O, Cyl No. O, Cyl No. O, Cyl No. O, Cyl No. O, Cyl No.so3/0r so3/02 so3/04 so3/06 so3/08 so3/09Mix Cyl No Mix Cyl No Mix Cyl No Mix Cyl No Mix Cyl No Mix Cyl No
so3/01 so3/04 so3/08 so3/10 so3/07 so3/1 I
Comp
Mixture cylinder HP and LP HP. I60 B HP- I65 B HP- I60 BLP-5.4 B LP-5.6 B LP 5.4 B
HP. I6O B HP. I6O B HP - 160 BLP 5.7 B LP-6 1B LP.6.6 B
Demand 50 LPM Suction
Valve Flow rate
Open posi t ion
PRSV Closed position
Inhalat ion
Valve Exhalation
box/chest
105-170 mm WC 170> 40 LPM 6050-100 mm WC 60165200-450 mm WC 2'7 1/330< 0.55 LPM 0.4'7< 0.55 LPM O.42
l6 ' t 126 1545 0 5 8 4 55U13 80/90 53t70315/370 350/405 225t2310.49 0 .49 0 .500.49 0 .48 0 .49
156 17345 406U64 76t8s320t435 277/321Not tested 0.49
Nor tested 0.49
TABLE 3
Functional evaluation of Russian IDA 59 (M) breathing bag components
Description ofTest as per BR
Comp.
BB NoE-44 B BB NoE-35 B02 Cyl. 4842 02 Cyl. 4316Mix Cyl 4316 Mix Cyl 4210
BB NOE-38 B BB NoE-32 B BB NoE-54 B02 Cyl. 47Q2 02 Cyl. 4294 02 Cyl. 4130Mix Cyl 4301 Mix Cyl 4301 Mix Cyl 1445
NormalRange
Mixture cylinder HP and LP HP- I60 BLP.5.6 B
HP-160 BLP-5.9 B
H P . I 7 0 BLP 5.7 B
HP- I70 B HP- I70 BLP 5.7 B LP-5.6 B
Demand 50 LPM Suction
Valve Flow rate
Open position
PRSV Closed position
Inhalat ion
Valve Exhalation
box/chest
1 0 5 - 1 7 0 m m W C 1 5 9> 40 LPM 5950-100 mm WC 56/64200-450 mm WC 2181236< 0.55 LPM Not tested< 0.55 LPM Not tested
1 6 86 87 0t'7 6263t276Not testedNot tested
t675 374t83234t239Not testedNot tested
1 7 2 1 7 06 4 5 964t'17 64t7 |271t322 220t245Not tested
Fig. 3 : Shows inflation status of the Bag in the RCC testwith author holdine manometer.
Jour Marine Medical Society,2007, Vol.9, No.2
Fig.4 : Shows swimming pool exercise.
89
TABLE 4
Technical evaluation of swimming pool trials (Date : 23-06-2007 1000 hrs)
Set HP/LP. Initial HP/LP Post Dive Gas Consumed Duration of Observationthe dive bv the divers
Remarks
Oxygen Mixt OxygenBA NO 8 /RHY 175t6 .2 t75 t5 .4155/6 .1
Mixt Oxygen Mixt14015.4 20 LTRS 15 LTRS 2l Mins
BA NO 5/RHY
BA NO 6/RHY
BA NO 7/RHY
t7 5 t5 .6 17 5 t6 .2 r40 t5 .7
165/5 .5 178/6 .2 t50 t5 .7
l7 5 t6 .3 r ' t 5 t5 .6 140t6 .4
Increasedbuoyancy pressureon the back of theneck breathingcomfortable
-same as above-
-same as above-
Hard breathing isnoticed at the endof the dive, dueto slipage of nutin ADV.
Breathing normal,buoyancy more
More buoyancy,breathing normal,neck discomfort
Buoyancyvariations cannotbe explained onth€ basis of thedata onconsumptionduring dive.
- same as above-
Gas consumptionis more duringthe dive.
ADV adjusted andflow restored thediver wascomfortable inthe beginning ofthe dive andduring the entireperiod of dive.
Gas consumptioncommensuratewith the dive
Consumptioncommensuratewith durationof dive
lncreasedconsumption ofgas in shorterduration ofthe dive
14016.2 35 LTRS 35 LTRS 27 Mins
14516.2 15 LTRS 33 LTRS 15 Mins
t2)t5.7 35 LTRS 55 LTRS 30 Mins
BA NO I/IHY
E 32IB/RHY
t 7 5 t 6 . 2 t 7 5 t 5 . 5 1 5 0 / 6 . t
t65 t5 .9 r7 5 t5 .6 140/5 .5
l l0/5.3 25 LTRS 65 LIRS 3l Mins
t40ts.5 25 LTRS 30 LTRS 19 Mins
E 4,YBIRHY 17015.6 17015.7 160/5.6 14515.6 l0 LTRS 25 LTRS 07 Mins -same as above-
INFERENCE AND CONCLUSIONSl) Observations on the increased buoyancy cannot be evaluated on the basis of technical data delivered from trials. Theobservations are mainly attributed to subjective feelings of the divers and do not have any semblance on the performanceof the sets undcrwater. 2) Consumption pattern of the indigenous breathing apparatuses and the Russian IDA59M sets ismore less same for the duration of the dive. 3) Defect in the ADV was found to be due to loosening of the check nutwhich was rectified immediately after the dive and its performance was again evaluated on the t€st rig. 4) Performance ofboth indigenous and Russian sets was comparable.
consumption pattem and other data collected fromthe simulated dives. It was therefore decided toincorporate a sensitive manometer in the breathing
w
circuit to measure the actual pressure inside the bagduring the simulated RCC Dive.
However no significant inference could be drawn
Jour Marine Medical Society, 2407, VoI.9, No. 2
TABLE 5
Technical evaluation of RCC trials : lE Mtrs (Date : 25-06-2007 1000 hrs)
Set/Wearer HP/LP Initial HP/LP Post Dive Gas Consumed Duration of
the dive
Observation Remarks
by the divers
*
?i
DOxygen
BA NO 0ZSurg 18016.2Cdr CS Saxena
Mix t Oxygen Mix t Oxygen Mix t180/5.4 160 l l0 20 LTRS 50 LTRS
Breathing
52 Mins comfortable. Bagwas found to inflateduring surfacing.Inhalat ion smoothand comfortable.Exhalation againstresistance
A pressuer gauge
attached to one ofIndigenous andone Russian IDA59 M set forassessing thepressure changesascent and descent.
No pressurevariation was
recorded duringof the dive. It wasdecided to repeatthe RCC dive up to50 meters forfurther evaluation
of the set.
Remarks By o/lETS : In Sr No. 4
t20
m
86
v
qi
r06
\2
l l6
BA NO 05/Cdr Verma
BA NO O7lCdr Verma
BA NO 06/Lt A Datta
BA NO 0l/SurgCdr Saxena
r80 /5 .6 180 /6 .2 r60
r80 /5 .5 180 /5 .6 160
r80 /6 .3 180 /5 .6 160 r r 0
180t6 .2 180/5 .5 160 120
E 44lB/Surg Lt 180/5.7 180/5.6 160Cdr P Anand
E 32tBt 180/6 .0 180/5 .7 120Lt A Dana
20 LTRS 55 LTRS 52 Mins Breathingcomfortable. Bagwas found to inflateduring surfacing.
20 LTRS 60 LTRS 52 Mins Breathine
"o.fortof,le. B"g
was found to inflateduring surfacing.
20 LTRS 70 LTRS 52 Mins Breathinecomfortaf,le. Bagwas found to inflateduring surfacing.
20 LTRS 60 LTRS 52 Mins Breathingcomfortable. Bagwas found toinflate duringsurfacing.
80 20 LTRS 100 LTRS 52 MinsBreathingcomfortable. Noinflation noticedduring surfacing.
120 60 LTRS 60 LTRS 52 Mins Breathingcomfortable. No
inflation noticed
during surfacing.
tzl
rmedl%
-tn
9. No.2
f135
t39
INFERENCE AND CONCLUSIONS
l) Consumption pattern of the indigenous breathing apparatuses and the Russian |DA59M sets is more or less same for
the duration of the dive. 2) Intrinsic pressure in the breathing apparatuses (both tndigenous and Russian) was recorded by
special pressure gauge did not show any significant pressure in the breathing bags in ambient pressure variations.
3) Performance of both indigenous and Russian sets was comparable except for the variation in the breathing resistance to
exhalation. 4) Final inference can only be drawn after completion of 50 meters RCC test. 5) However, according to the
rep ETS who conducted the dive all four Indigenous bags had shown inflation during ascent.
from this modification. The pressure inside the bagf luctuated wi th respi ratory cyc le which wasexpected.
Jour. Marinc Medical Society, 2007, Vol.9, No.2
CONCLUSIONS AND RECOMMENDATIONS
During the post trial deliberations and analysisof the consumption pattern during the dive it was
9I
TABLE 6Technical evaluation escape trials : 30 Mtrs (Date : 27-06-2007 1000 hrs)
Set HP/LP Initial HP/LP Post Dive Gas Consumed Diver's name Observation
by the divers
Remarks
Oxygen
BA NO 6/ 180/5.7indigenousHydro Suit(Bib)
Mixt Oxygen Mixt Oxygen
r35/6 .1 160 r00 20 LTRS
Mixt
35 LTRS Lt CdrA Datta
90 30 LTRS 45 LTRS P Sarkar
The rate of ascentwas too fast andhad to make aconscious effort tocontinuously breatheout. There was backpressure in the setdue to which theentire air whileexhaling wasescaping back inthe hydro suit
Due to excess flowcoming to breathingbag, ascent rate istoo fast
No water ingressfound in hydrosuit
No water ingress
found in hydrosuit
BA NO 0 l / 180/6 .1 135/5 .3 t50RHY
B A N O 5 / 1 8 0 / 6 . 1 1 4 0 / 6 . 3 t 7 0
RHY
BA NO 7 / t80 t6 .2 135/6 .1 180
IndigenousHydro suit(zip)
BA NO Z 180/6.0 135t5.4 178
RHY
E 32tBt 180/5.9 135/5.5 r40RHY
E 44tBt 180/5.6 r35t5.4 r78RHY
100 l0 LTRS 40 LTRS J Singh I Excess flow in
breathing bag2 Ascent rate fast
00 LTR 135 LTRS PK Biswal I Continuous flow
to breathing bag2 Ascent rate toofast 3 excess flowto breathing bag4 demand valvenot working
02 LTRS 15 LTRS N Kumar I Excess flow of
demand valve2 Ascent rate toofast 3 25 Sec timetaken for escapefrom 30 mt.
ll0 40 LTRS 25 UIRS Sindu Kumar Normal.No Observation
02 LTRS 45 LTRS SKReddy NormalNo 0bservation
t f
t j
t20
90
92 Jour Martrc Medical Society,2007, Vol.9, No.2
<E *o
lo
6
<5 *q
9o
di
:l|r
L
tl^
TA
BL
E 7
Esc
ap
e to
we
r tr
ial
: 3
0 M
T
Fu
nct
ion
al
eva
lua
tio
n (
aft
er
tow
er
tria
l)
of
bre
ath
ing
ba
g c
om
po
ne
nts
: R *. q tJ E -\ s z L
Co
mp
on
en
ts D
es
cri
pti
on
of
tes
t
No
rma
l
ran
ge
B B
ag
No
. l.
B B
ag
No
.2
B B
ag
No
.7
O, C
yl.
0l
O, C
yl.
SO
3/0
2 O
,Cy
l. 5
03
/06
Mix
Cy
lSO
3/0
1 M
ixC
ylS
O3
/04
Mix
Cy
lSO
3/1
0
B B
ag
No
. 5
B B
ag
No
. 6
B B
ag
E4
4B
BB
ag
E3
2B
(Ru
ss
aia
n)
(Ru
ss
ian
)
O,
Cyl
. SO
3/0
8 O
, Cyl
. SO
3/0
9 O
rCyl
.48
42
O
rCyl
. 42
94
Mix
Cy
l SO
3/0
7 M
ixC
ylS
O3
/ll
Mix
Cy
l 43
16
Mix
Cy
l 43
01
De
ma
nd
va
lve
PR
SV
Va
lve
Bo
x/C
he
st
50
LP
M
suct
ion
Flo
w
rate
Op
en
po
sit
ion
Clo
se
d p
os
itio
n
Inh
ala
tio
n
Ex
ha
lati
on
10
5-1
70
mm
WC
> 4
0 L
PM
50
-10
0 m
m W
C
20
0-4
50
mm
WC
< 0
.55
LP
M
<0
.55
LP
M
10
9
64
6l/
64
2t5
t24
0
No
t te
ste
d
No
t te
ste
d
t66
67
75
l.q
I
26
5/2
82
No
t te
ste
d
No
t te
ste
d
14
94
0 52
/62
36
5t4
'7
5
No
t te
ste
d
No
t te
ste
d
15
4
45
58
t61
32
5t4
20
No
t te
ste
d
No
t te
ste
d
16
5
50
10
4
32
7 t3
7 5
No
t te
ste
d
No
t te
ste
d
r63
67
68
/70
23
6t2
43
No
t te
ste
d
No
t te
ste
d
t63
46
74
26
2t2
69
No
t te
ste
d
No
t te
ste
d
c
-?
5,
F
I g
I
"*
H
EF
+
iHf$
lqF
fEE
3 1$
ff IEE
FI*
FE
FF
$g*
Y-
3Y
a*
,at'
1
+"*
=s
lg
g,
ie+
a $[i
lu
';tr 5
+ iai +
+e
3g
ifl1
ig
ig+
* *Fiu
#is
,rd
*.=
E E
g
3:
n1
s il*
;*
+ i
+*i
$$
s;i ;
n6
ssq
+[;
gg
$;
$g
[:r $
e i$? $
?s$+
riE+
ie
I ;HrE
$F
E'E
+E
fl5
qa
=
?
*eg
E
rlq
i$E
la
€E
i 3
F?
o3
5 g
ig{
[;i F
* $F
$ F
FF
$FgF
5 H
ElE
gF$ *c
IgE
c\o
SUBMARINE ATMOSPHERE REGENERATION SYSTEM: PRESENTSCENARIO AND FUTURE TREND
Surg Commander DK Ghosh-
ABSTRACT
Presently India has three different types of submarines of Russian and German origin. System of atmosphereregenerat ion on board submarines are di f ferent in submarines of d i f fereut or ig in. Submarines or ig inatedfrom Russia utilizes the chemical KO, (Potassium Superoxide) for both CO, absorption and O" rcgeneration onregular basis as wel l as emergency/rescue refuge scenar io. This system of regenerat ion is passive, independentof electrical supply or integrity of ventilation system, works even in extreme cold environment and portable innature but the chemical needs to be handled by crew for system to star t . I t is corrosive, helps in burning ofinf lammabte mater ia l when comes in contact and is cost ly . German or ig in submarines use cheapcr Soda l imechemical pre-filled in disposable cartridge to be fitted readilj, in ventilation system for absorption of CO,. HighPressure cyl inders f i l led wi th O, is used for replenishment of O" for regular use of atnrosphcre regenerat ion.This system is less messy to handle, chemical does not come in contact wi th the crew dur ing operat ion of thesystem, does not generate much heat and is cheap on running cost . The s1'stem needs an act ive blower systemfor the ai r to go through the chemical ; therefore th is is dependent of i r r tact vent i lat ion system and avai labi l i tyof e lectr ical power, For escape systern, the German or ig in submarine uses Potassium Chlorate candle togene ra te O , and f . i t h i um Hyd rox ide based chem ica l t o abso rb CO, . Bo th chem ica l s a re supp l i ed i n such aquantity that the system should last for entire crew for not less than nine hours. Other method of regenerationut i l izes electro lys is of water to generate O, whereas water solut ion of NIEA is used as CO, scrubber. Af terconsidering all the methods of atmosphere regeneration, it is recommendcd that for a diesel electric submarine,system of atmosphere regenerat ion best be at ta ined by chemical nethod separated for C0, absorpt ion and O"regeneration, For emergency survival at compartment, K0, based regeneration is suitable due to its portable innature, ef f ic ient even in cold environment and does not require any electr ic i ty to run.
Key Words : Submarine, Atmosphere regenerat ion.
INTRODUCTION'p'esently
Indian Navy has three types of SubmaI r ines:-
A) Russian Origin
i) Vela Class (Foxtrot Class) and
ii) Sindhughosh Class (877 EKM)
B) German Origin
iii) Shishumar Class (SSK)
Once the submarine dives, it remains cut off fromoutside world and the atmosphere inside remainscut of f f rom outs ide envi ronment and star tschanging instantly. Pressure remains same - barringminor changes, which is ins igni f icant . But thecomposition of air starts changing, moment the upperlid is shut. Main composition, which is N2, remains
una f fec ted bu t t he oxygen gas s ta r t s ge t t i ngdepleted due to consumption by human beings andCO, starts building up due to metabolic effect ofl iving beings inside. Apart from these two gases theother main change in atmosphere is H, gas evolvedfrom batteries meant for propulsion of submarine insubmerged condition. This gas is metabolically inertbut poses a fire hazard. Other gases, which areevolved, are minimal in nature and do not pose amajor problem regarding habitabil ity on board asubmarine.
Main aim of the atmosphere regeneration in asubmarine is to replenish the O, and removal of CO,.Other gases are generally removed by special filtersplaced in the l ine of venti lation system.
On board the following parameters are taken as-
'PMO, INS Vajrabhau
94 Jour Marine Medical Societv. 2007, Vol.9, No.2
ind icator /cut of f l imi ts for the purpose ofregeneration :-
i) Upper limit of COrTo - 0.87o by vol. for a longduration of Sailing/dive, which is consideredmore than 3 days.
ii) l.3Vo of COrlevel by vol is taken as cut off limitwhen sailing for short duration.
i i i) 0.57o by vol. of CO, as cut off l imit whenconsidered for very long duration of sailing.
iv) Generat ion of CO, by a person var iesconsiderably depending on individual variationand workload. Generally 22.4 ltr lmanlhrproduction of CO, is taken for calculationpurpose. O, consumption of 25lltr/per man/hris taken for calculatton.
v) Pre-Regeneration time : This is the time takenfor the CO, percentage to built up from baselevel to maximum permissible level once thesubmar ine d i ves . Th i s i s t he t ime when
'regendration has to be resorted to.
vi). F9r cdlculation of pre-regeneration time CO,,
' level is taken as cut off limit as this will attainearlier than the cut off level of O, which has tofall from 20.87o to below l87o which will takelonger time.
Air regeneration on board SUBMARINE may bedivided in two broad headings :-
i) Regeneration on a regular basis,
ii) Emergency situation.- during escape.
AIM
The aim of this presentation is to bring outdifierent mode of air generation system existing onbroad submarine, the future trends, study theirbenefits and shortcomings.
METHOD FORAIR REGENERATION RUSSIANORIGINSUBMARINES
System of air regeneration in general is differentin different types of submarines at present scenario.In Russian origin submarines of both Vela class andSindhughosh class, chemical means are employedas a regular measure for both CO, removal and O,supplementation. Chemical Potassium Superoxide(KOr) in asbestos in sheet form - commonly know aschemical O-3 (O-three) is employed.
Jour. Marine Medical Society, 2007, VoI.9, No. 2
The following reaction takes place.
4KOr+2COz4 K" CO3 + 30, + Heat
4KO, + 24O -+KOH + 30, + Heat
I t is seen that both O, generat ion 'and CO,absolption is effected with the same chemical.
Similar system of air regeneration is used forsurvival dur.ing escape procedure while stayinginside the escape compartments.
METHOD OF AIR REGENERATION GERMANORIGINSUBMARINES
In Shishumar Class (German Origin) the arrregeneration is being carried away by independentO, supplementation and CO, absorption. O, is storedin high-pressure O, cylinders. In case of requirementof O, on board, the gas from high pressure stored O,cylinder is bled in controlled manner and level ofOrTo brought up to the level of l9-2OVo.
For scrubbing of CO, - Hydroxides of Alkalimetals - Sodium, Potassium and Calcium called sodalime is used which are packed in disposable cartridgeof approx 4 Kg chemical in each cartridge. These arecarried on board and when required, these cartridgesare placed in ventilation system. Depending on thestrength of crew on board number of cartridges isput into action. Chemical reaction is shown below.
NaOH (SodaLime) + CO, -{lla, CO, + HrO
CaOH(SodaLime) + CO, *CaCOr+ H,O
Atmosphere regeneration during escape fromShisumar class of submarine is done as follows :-
i) O, regeneration is carried out by burning O,candle. Reaction is shown is below :-
2KCLO3 (ChlorateCandle) -9KCl + 3Or+ heat
i i ) CO, is absorbed using L iOH (L i th iumHydroxide). Reaction is shown as below :-
2LiOH+CO2{ i2COr+HrO
Advantage of using LiOH is that for a smallervolume and weight of Lithium Hydroxide largeramount of CO, is absorbed. This saves space in anotherwise crammed rescue sphere.
The capacity of O, generation and CO, absorptionis maintained in such a way that the amount ofchemical suffices for the ertire crew of the RescueSphere for not less than 09 hrs. This time has beencatered for any possible decompression schedule,
95
which might arise from any, overstay on board underpressure.
Both the processes followed in Russian type andGerman type has got its merits and demerits.
In Russian type : Both the goals are achieved bya single chemical. The system is not in-built. It isportable and efficient even in very cold environment.It is passive in operation. But it generates heat andis quite messy in handling. Moreover the chemicalis quite costly.
In German type : The system is easy to operateand clean. Cartridges are disposable. But the systemneeds an active blower system to drive the airthrough the chemical, which requires electrical powerand cannot be done in case ofelectrical failure.
OTHBR METHOD OFAIR REGENERATION
Though not practiced in Indian submarine, butother system of atmosphere regeneration is beingpracticed especially in the situation where electricalpower is in abundance and the submarine is requiredto be put to sea for very long time. Here O, isgenerated by electrolysis of the water. O, is usedand H, is dumped overboard. Dur ing normaloperat ions, submar ines employ an e lect r ica l lypcwered regenerative scrubber system to removecarbon dioxide (COr) from the atmosphere using awater solution of Monoethanolamine (MEA). Whencold, MEA takes in CO' when heated, MEA givesup the CO,. On submarines, the CO, is pumpedoverboard.
FT.JTURETREND
In general the regeneration system presently inuse in diesel - electric submarines uses chemicalmeans to absorb the CO, generated. However, thereare significant problems related to the use ofchemical means with or without electrical power.They include health concerns, limited stores thatmay not support the crew until rescue and storagespace requirements. Consequently, there is a strongneed to develop an alternative CO, scrubbing systemfor submarine use that uses either no power, limitedhuman power, or the ship's main batteries. One reportof TIIE ARTEMIS PROJECT Life Support Systemsreviews two methods and some recent testing oftheir effectiveness, for such removal of CO" usine
96
seawater by: l) direct water contact with the air or2) indirect contact in conjunction with a membranesystem. Both methods were shown to be effectivein removing CO, from the closed - space atmosphere,thus offering the potential for greatly extendingsurvivability during a DISSUB scenario. However,the feasibility of these techniques for the DISSUB,and the best way to design the system, remains tobe investigated.
Schematic diagram of a reusable CO, scrubbersystem by EADS is shown in the Fig. l.
RECOMMENDATION
Atmosphere regeneration is vital part of asubmar ine operat ion. Durabi l i ty of a s teal thsubmarine to remain underwater depends on thecapability of atmosphere regeneration. Present dayregeneration of captive atmosphere is dependenton chemical means and these chemicals are of onetime use. In Russian system - the regenerationinvolves physical handling of chemicals by the crewto put th is to the por table system. Chemical rscorrosive, helps in burning of inflammable materialsand has relatively short shelf life. Moreover thischemical is costly.
In SSK class of submarines, chemical is pre-packed in cartridges, so there is no direct contact ofthis chemical to the crew while loading into thesystem and does not generate much heat. The wholesystem is neat and not at all messy. As a basis ofregular use, cost-to-cost analysis shorvs that man-hourregeneration of atmosphere is much less costlierthan that of Russian system.
Frctl Air AO2 Utposd
F i g . l
Jour Marine Medical Society, 2007, Vol.9, No.2
System of regeneration of atmosphere as a (load on A/C), corrosiveness of chemical areregular basis is recommended to be of separate considered. For damage conffol and escape refugemodules utilizing cheaper soda lime chemical and purpose, KO, (Potassium Superoxide) based systemstored O, gas. should be kept as emergency as this is portable type
and in case of damage the ventilation system maycoNcLUSroN notbe available.
r pue to restrictionof power, regeneration systemcannot depend on electrically driven one and hence REI.ERENCFS
option is left with the use of chemical, which is of l. Manual 103 - Recue Sphere.
r' one time use. System of atmosphere regeneration 2. Manual 407 - Ventilation system, Air regeneratingutilizing separate modules for CO, and O, has got plant and Air treatment system.advantage of being cleaner in operation, quicker to 3. The Arrimis project (htp://www.asi.org);put on use and cheaper' 4. co, scrubber (http://www.naval'technology.com/
System of atmosphere regeneration used on conractors/hvac/dorniers)
board SSK type of submarine is consi.dered bener 5. Submarine Air Revitalisation Unit - Description andcompared to system used in Russian type, when the Operation Manual.factors of cost, ease of handling, heat production 6. M9MDA.
Jour. Marine Medical Society, 2U)7, Vol.9, No.2 97
SMERG (2003-07) - JOrNT EFFORT' FOR RESCUE OF PERSONNELFROM A DISABLED SUBMARINE
Surg Cdr GD Bhanot.
ABSTRACT
High r isk naval and marit ime civi l ian operations, executed with dynamism and to the l imits of platformcapabil i t ies as well as human endurance involve an inherent element of danger. Submarines and othersubmersibles by virtue of their role and environment in which they operate, qualify in this category with addedsignif icance. These very qual i t ies of a submarine that makes i t such a formidable weapon, makes i t equallydifficult to be located and reached in times of crisis.
However, the art of submarine rescue, which is still evolving, is replete with difficulties and complexities. Thishas been clearly demonstrated by the fact that there have been only a few successful escapes from distressedsubmarines, despite about 70 known sinking in peacetime.
Submarine design has come of age since the days of the 'Tirrile'. Much thought has gone since those early daysin re-defining, re-val idating, experimenting and researching on the submarine safety aspects especial ly afterthe loss of the Thresher in 1963. The loss of Kursk in Aug. 2000, has brought to fore that 'Nature' is still notconquerable.
The quantum of work put in to improve the design of submarines, to enhance their safety and rescue them hasbeen phenomenal, but st i l l the accidents to these war making machines cannol be prevented, whether due tohuman errors or due to material fat igue.
This presentation aims to bring out the various modali t ies of 'Joint Effort ' for rescue of personnel from adisabled submarine and to suggest a possible framework in realising this as envisaged in SMERWGs from 2003to 2007.
Presently the Indian delegation attends the SMERWG as observers. However, given the number of submarinesheld in our inventory and as holders of rescue assets such as the diving bell on INS Nireekshak, India needs toassert itself in forums of such importance. It is therefore a must to actively participate in SMER related jointexercises and become a member of the SMERWG at the earliest.
Key Words : Submarine, SMERWG
INTRODUCTION
lfigtt risk naval and maritime civilian operations,I lexecuted with dvnamism and to the l imits ofplatform capabilities as well as human enduranceinvolve an inherent element of danger. Submarinesand other submersibles by virtue of their role andenvironment in which they operate, qualify in thiscategory with added significance. These very quali-ties of a submarines that makes it such a formidableweapon, makes it equally difficult to be located andreached in times of crisis.
The idea of submerging beneath the waves andcatching the enemy unawares had always occupiedthe mind of the f ight ing men. Once th is was
achieved, the realisation dawned that mastering theunderwater world included amongst other aspects,the ability to render succor to the crew of distressedsubmarines.
However, the art of submarine rescue, which isst i l l evolv ing, is replete wi th d i f f icu l t ies andcomplexities. This has been clearly demonstratedby the fact that there have been only a fewsuccessful escapes from distressed submarines,despite about 70 known sinking in peacetime.
Submarine design has come of age since the daysof the 'Turtle'. Much thought has gone since thoseearly days in re-defining, re-validating, experimentingand researching on the submarine safety aspects
'C lassi f ied Special is t , Underwater Mar ine Medic ine
98 Jour Marine Medical Society-, 2M7, Vol.9, No. 2
especially after the loss ofthe Thresher in 1963. Theloss of Kursk in Aug. 2000, has brought to fore that'Nature' is still not conquerable.
The quantum of work put in to improve the designof submarines, to enhance their safety and rescuethem has been phenomenal, but still the accidentsto these War making machines cannot be prevented,whether due to human errors or due to materialfatigue.
AIM
The aim of this presentation is to bring out thevarious modalities of 'Joint Effort' for rescue ofpersonnel from a disabled submarine and to suggesta possible framework in realising this, as envisagedin SMERWGs fiom 2003 to2007 .
SMERWG
The Submarine Escape and Rescue WorkingGroup Seminars Organised by the NATO and othernon aligned countries from 2003 to2007 are a timelyinitiative in this direction. They take place at a timewhen the complexities and pitfalls of the businessof submarine rescue have received global exposure.It would be an appropriate launch pad for bringingto the fore 'Unity of Effort' in the global context,should such an eventuality arise anywhere, any time.Submarine Rescue needs to be understood as a'humanitarian need' rather than a Naval or Militaryoperation. Since people across the globe lend theirhands in all hull of a distressed submarine to mvmind certainly falls in this category.
The Submarine escape and rescue working group(SMERWG) meet ing is an annual meet ing ofsubmar ine operat ing NATO and non-NATOcountries to discuss and implement as far as possiblecommon standards and operating procedures relatedto Submarine escape and rescue (SMER). Countriesa re i nv i t ed t o p resen t va r i ous resea rch anddevelopmental actions and exercises uhder taken insupport of SMER and to deliberate on various lesionslearnt. These actions are considered inescapable,as it is amply clear that no country in the worldtoday can guarantee successful SMER through itsown resources. Developing or procuring assetsavailable off the shelf individually is also not costeffective. Hence there is a need to pool in theresources related issues through exercises and
Jour. Marine Medical Society, 2007, VoL9. No.2
discussions with all submarine operating nationsand carry out research and development on a costsharing basis involving civil entrepreneurs/firmswhich have the requisite technology.
The agenda points for the succeeding SMERWGmeeting are decided before the closure of themeeting. Various countries then work these uponand the results are brought out at the plenary by aformal presentation. Though presently a NATOcountry chairs the meeting and the presenters aregenerally from the NATO nations barring an oddinclusion there is a conscious decision to bring inthe non-NATO countries for active participation.Towards this end the SMERWG 04 meeting was heldin St. Petersburg, Russia. Presently Great Britain isthe sponsor nation for India and is responsible forcoordinating all actions with regards to the SMERWGmeeting.
The convening order for the SMERWG meetingis issued by the Military Committee Marit imeS tanda rd i za t i on Boa rd (MCMSB) . The UKcoordinating member is through the convening orderrequested to forward the names of delegates alongwith relevant information for obtaining the necessarysecurity clearances. The UK Embassy on the basisof the above enquiries the details of the Indiandelegation from Directorate of Naval Intelligence.
A list of non-NATO nations invited along withthe sponsor nation is as appended in Table l.
A l ist of nations invited on regular basis is asappended in Table 2.
SUBMARINEACCIDENTS
In order to highlight the objectives of SMERWGover the years it is important to ponder over a fewSubmarine accidents that have taken place between200G07.
Kursk Accident
On Augus t 14 , 2000 , Russ ian au tho r i t i esannounced that one of their newest cruise missilesubmarines, the Kursk, had sunk with all hands. TheKursk is a cruise missile submarine, called the type949a "Antey" class by the Russians, code namedthe Oscar II by NATO. It is not a ballistic missilesubmarine, but is intended to attack and destroy anaircraft carrier battle group rlsing torpedos and short
99
TABLE 1List of invited non-NATO nations and theirrespective sponsor nation
S. No.
2 .
J .
4 .
5 .
6 .
8 .
9 .
1 0 .
l l .
12 .
1 3 .
t 4 .
1 5 .
1 6 .
t 1 .
Non-NATO Nat ion
Argent ina
Australia
Brazil
Chile
China
Colombia
Ecuador
India
Japan
Malaysia
Pakistan
Peru
Singapore
South Africa
South Korea
Thailand
Venezuela
Sponsor Nation
Canada
USA
Canada
Canada
Great Britain
USA
USA
Great Britain
USA
USA
Great Britain
USA
USA
Great Britain
USA
USA
USA
l .
2 .
J .
4 .
5 .
6 .'7.
8 .
9 .
1 0 .
l t .
12 .
1 3 .
1 4 .
1 5 .
1 6 .
1 7 .
t 8 .
1 9 .
20.
2 1 .
2 2 .
2 5 .
24.25 .26 .
TABLE 2
List of country delegation that attended SMERWG
S. No. Country S. No. Country
Fig.2
position which was North-West of Ireland.
During the transit the Chicoutimi encounteredheavy seas and at about 2200hrs on 05 Oct, waterentered the submarine through the conning toweras waves broke over its sail. This water seepedthrough the decks and reached the ships main DCcables running below the Commanding Officerscabin. As the insulation on the connecters was notwatertight it resulted in bringing down the insulationwhich intern led to electrical arching. The fire brokeout at about 2300hrs on 05 Oct and could only becontained by l335hrs on 06 Oct 05. The submarineremained without power or propulsion on surfaceresulting in casualties.
San Fransisco Incident
USS San Fransisco a SSN 7 I l, Los Angeles ClassSubmarine 'ran aground' on an underwater obstacle,presumed to be a sea mountain on 08 Jan 05 at adepth of 525 ft. The inability to evacuate injuredpersonnel due to high sea state, low free board andconfiguration of bridge hatch was a key issue, which
Jour Marine Medical Society,2007, VoL9, No.2
Algeria
Argentina
Australia
Bulgaria
Brazil
Canada
France
Germany
Greece
India
Italy
Netherlands
Norway
Pakistan
Poland
Ecuador
Portugal
Russia
Singapore
Spain
South Africa
Sweden
Turkey
Ukraine
United Kingdom
USA
range sea skimming cruise missile (Figs. 1,2).
The Chicoutimi Incident
The upholder class submarine re-named HMCSChicoutimi was to transit on surface till her diving
100
Fig . l
hampered in emergency evacuation of causalities.In addition criticality of bringing medical supporton board by helicopter was also a cause ofconcern.The st retcher present ly used onboard USsubmar ines proved inadequate for casual tyevacuation. One Sailor died and almost the entirecrew was injured (Figs. 3,4).
Explosion onboard Royal Navy Submarine HMSTireless
The incident occurred on 20 Mar. 07, when theSubmarine was under Artic ice patrol. Detailsunknown as it has been kept as CLASSIFIEDINFORMATION.
SUBMARINE ESCAPE EQUIPMENT PANEL (SEE)
Purpose and Mission
The purpose of setting up of the panel was toprovide escape equipment usage and training inputto the SMERWG regarding all aspects of submarineescape. The mission of the panel is to:-
a) Provide a forum for minor and major users ofsubmarine escape community
b) Facilitate the exchange of information betweenescape equipment users
c) Identify escape equipment problems andsolutions
d) Monitoring of equipment defects.e) Design review
0 Share proposals for equipment modificationsbetween user countries
g) Provide an avenue for customer feedback tomanufacturers
Fig. 3 : Damaged forward portion of the submarine
Jour. Marine Medical Society, 2007, Vol.9, No. 2
h) Identify country point of contact
) Identify tower and air system interface issuesk) Identify training issues and capabilities
Goals set
The SEE panel had set their goal to achievecommonality of escape equipment and training e.g.:-
i) CO, absorption by micropore, battle curtainsand soda lime
ii) Oxygen candlesiii) Emergency lighting by LEDiv) Atmospheric detection equipmentv) SEIEMkI0
Mission
The following missions are assigned to thispanel:-
a) Facilitate the exchange of information betweenowners, operators and potent ia l users ofsubmarine rescue assets
b) Identify rescue asset problems and solutions.c) Share proposal for equipment modification
between user countriesd) Consider and where appropriate, develop or
revise standardisation proposals, STANAGSand related publications to rescue asset aspectsofSMER.
e) Establish and maintain liaison with other NATOand international bodies and groups concernedwith rescue activities related to SMER
f) Monitoring of industry development of rescueassets and supporting equipment technology
g) Identify training issues and capabilities
Fig. 4 : Difficulty in taking strercher out of the hatch
101
Rescue Asset Panel (RAP)
A new panel for the rescue assets had been setup in 2004 to provide rescue asset operators, usersand potential users inputs to SMERWG regardingall aspects of submarine rescue asset ownership,capabi l i ty management and operat ion. Whi ls tdelegates from NATO countries participating in theSMERWG are to be members of this panel, delegatesfrom par tnership for peace (Pfp) nat ions,Mediterranean dialogue and sponsored non-NATOnations are permitted to attend the panel meeting asobservers. The rescue asset panel is directed to makean annual report on pertinent rescue asset issue tothe SMERWG plenary committee.
Mission of Rescue Asset Panel
The fo l lowing miss ions are assigned to th ispanel:-
a) Facilitate the exchange of information betweenowners, operators and potent ia l users ofsubmarine rescue assets
b) Identify rescue asset problems and solutionsc) Share proposal for equipment modification
between user countriesd) Consider and where appropriate, develop or
revise standardisation proposals, STANAGSand related publications to rescue asset aspectsofSMER
e) Establish and maintain liaison with other NATOand international bodies and groups concernedwith rescue activities related to SMER
f) Monitoring of industry development of rescueassets and supporting equipment technology
g) Identify training issues and capabilities
Exercises in survival conducted/co-ordinated bvRAP: STJRVTVEXO4
The US Navy at San Diego, using submarineberthed along side conducted SURVIVEX 04. Theexercise was carried out fol four days. Overboardwater temperature was found to be around 24oCSubmarine was covered by a white tarpaulin clothto simulate a sunken submarine. 90 volunteersparticipated in the exercise. Lithium Hydroxide Battlecurtains and Chlorate candles were used to keepCarbon dioxide and oxygen within normal limits. Nowater restriction was imposed on the volunteers.Since there was no power supply LED Battery lantern
t02
and Chemical means for lighting were used. Thevolunteers were tasked with their respective duties.Each volunteer was allowed to consume 1400 Kcalenergy/day. It was tbund that 35 personnel lostweight, apparently due to dehydration. Followingconclusions were drawn:
a) 1400 Kcal energy is sufficient for survivalb) Heat and Humidity are the main threats to
su rv i vab i l i t y i ns ide a sunken submar ine(Figs. 5,6)
Sorbet Royal 05
The Royal Netherlands Navy conducted exerciseSorbet Royal 05. The exercise commenced with apaper exercise SMASIIEX for shore organisation,where the ISMERLO web site was assessed to be apowerful tool forobtaining information. The HNLMSDolfijn submarine took part in sea phase of thisexercise. Technical improvements of escape suits,life rafts, gas analysers, CO, absorption curtains,CO, membrane gas absorption and reduction of CO"in the escape air system were validated. SRV LR 5and SRV 300 under took rescue. The submarineparachute assis tance group (SPAG) was a lsoexercised. The exercise provided an insight intoimportance of life rafts in order to survive in extremelycold waters. These lif 'e rafts would be deployed inplace of submarine indicator buoy. Life rafts will carry
Jour Marine Medical Society, 2007, VoL9, No.2
F ie .5 :SURVIVEX04
Fig. 6 : Photographs of sodalime curtains
out indication functionality in such a case. In-housemanufactured curtains fitted with used soda limewere also fund effective (Fig. 7).
NSRS
NATO Submarine Rescue System (NSRS) is beingdeveloped under joint collaboration of France,Norway and Britain. This SRV is likely to enter servicein late 20O7. The operating organisation of thisrescue asset is likely to be set up later this year, withthe agreement amongst owner nations, which wasratified by end 2005. The base facility had been setup at Breast, France in Apr. 2006. The trial asconducted from Jul to Oct. 2006 and the systemwould be used during Bold Monarch 08, Norway.This system would be capable of operating up to adepth of 600 M and would be able to engage withthe hatch of the DISSUB inclined up to 60'. Thissystem has transfer under pressure facility (6 bar)and would be fully air portable or could be deployedfrom vessels of opportunity (VOO), using portable
Fig.1 : 27 tons 15 rescuees SRVo 30 tonne SWL portable launch and recovery
system (PLARS)o Fully airportabler Minimises deck spaceo Swimmer-free High Sea State Launch & Re
covery 556 (5m swh)o Designed for rapid mobilisation, setting-to-
work and commissioningo Winches/HPUs/control systems etc. housed
in base assemblyo Requires 7 trailers/C130 aircraft
Jour. Marine Medical Society,2007, Vol.9, No.2
launch and recovery system (PLARS) giving it aglobal reach (Fig. 8).
SRDRS
This system would comprise of a pressurisedrescue module system (PRMS). This module wouldenable rescue ofpersonnel from a depth of2000 feetand is likely to be operationally available by laie2N7. In addition this would include Submarinedecompression system (SDS), which would providetransfer ofpersonnel under pressure capability. Thesystem would also incorporate a 4 X AtmosphericDiving System (ADS-2000). TheADS would be usedfor rapid assessment of the DISSUB condition, hatchclearing and delivery of emergency life supportstores (Fig.9).
OTHER NATO RESCUE ASSETS (Figs. 10, 11)
STANDARDISED NATO AGREEMENT(STANAGS)
STANAGS
These publications are Standardised NATOagreements to develop standardisation in the fieldof submarine escape. The idea is to develop acommon doctrine and standard procedures forsubmarine escape and rescue. The publications areamended as the basis of recommendations andlessons learnt from national exercises.
ISMERLO (OPERATIONAL DOCTRINE (OPD)PANEL)
ISMERLO Panel
The International Submarine Escape and Rescue
Fig.8 : Key components of NATO (UK, France andNorway) submarine rescue system (NSRS)
103
Fig. 9 : Pictures of submarine rescue diving and recom-pression system (SRDRS) of the US.Pressurized rescue module system (PRMS)r Rescue depth is 2000 feeto Carries 16 rescuees and 2 tenders per sortieo Rescue Ready late 2007o Submarine decompression system (SDS)o Two chambers: 62 patients simultaneouslyo Satura t ion decompress ion w i th med ica l
treatmento Charnber delivery in 2006. Transfer Under
Pressure (TUP) and Fleet capability in 2009o Assessment/underwater work system
(Atmospheric Diving System-ADS 2000)o Used for rapid assessment and hatch clearingo Delivery of emergency - Lit'e support stores
(ELSS Pods)r 650M no decompression obligationr Undergoingcertificationo Rescue ready by 2005
Liaison Office (ISMERLO) is a group of retired orcivi l ian personnel who are contracted and bi l letedwithin an establ ished NATO command/HQ workingexclusively fbr SMER. The ISMERLO works towards
104
Fig. l0: Atmospheric diving system - ADS 2000
Fig. l I : Pressurized rescue module (PRM)
provisioning of SMER advice round the clock torender assistance in response to an alert in respectof a disabled submarine (DISSUB) anywhere in theworld. The Supreme Allied Command for operationsdesignated All ied Submarine Command to establishand maintain the ISMERLO in Norfolk, Virginia(USA). The ofTice monitors SMER related activitres
Jour Marine Mcdical Society, 2007. Vol.9. No. 2
and provides a worldwide coordination capabilityand database for escape and rescue assets available.ISMERLO reports to the SMERWG via the ISMERLOpanel.
Goals envisaged for ISMERLO
There are several goals being pursued by theISMERLO.
a) Ensure information is readily available to affectSMER a t a l l t imes i nc lud ing accu ra temobilisation time for rescue assets
b) Integratecivil ianSARtoATP5T
c) Have provision to ensure better coordinationamongst various submarine rescue coordinationcentres (SRCC)
d) Include hospitals and other facil i t ies into theweb site
e) Formalise SOPs and standardise equipmentbased on US certitication in terms of SMER theworld over
f ) B r i ng SMER commun i t y t o t ab le us ingISMERLO as a facilitator
g) Evaluate various escape and rescue exercises
Coordination with operational authorities
Contacting ISMERLO in the event of a submarinedisaster is voluntary. However, there exists extensivescope for work ing in tandem wi th operat ionalauthorities of various non-NAIO countries. It hasbeen further clarified opelational commands and thatthere is a need to coordinate work in a healthymanner. This however did not preclude any nationfrom getting into a contract with another nation withwhom it has a pre-existing bilateral agreement orMoU. The capability of ISMERLO web site to carryout SMER is almost complete and that it should notbe neglected by submarine operating nations. Theexchange of information during the Chicoutimi andthe San Fransisco inc idents brought out thestrengths of the system.
RECOMMENDATIONS
The following recommendations are important forconsideration :-
a) Presently the Indian delegations attends theSMERWG as observers. However, given thenumber of submarines held in our inventorv
Jour. Marine Medical Societv, 2007, Vol.9, No.2
and as holders of rescue assets such as thediving bell on INS Nireekshak, India needs toassert itself in forums of such importance. It istherefore recommended that the service mustendeavour to actively participate in SMERrelated joint exercises and become a member ofthe SMERWG at the earliest
b) ISMERLO website is an excellent tool to gainrapid information on the availability of rescueready assets all over the world. As submariningis a risky profession there is a need to anticipateand be ready for any eventuality. The use ofthe website during SMASHEX is thereforerecommended
c) Survival exercises being carried out alongsideby some of the developed countr ies is anexcellent way to gauge the physiological andpsychological effects on stranded submarinersand is recommended to be carried out in ournavy
d) Using of the already existing technology andgetting inputs from the R & D field on mattersrelating to SMER and escape appliances couldplove to be cost beneficial and invcllvementwith SMERWG members is theretbre hishlvrecommended
CONCLUSION
It is amply evident that there is a consensus inthe view that an evolution like SMER would requireefforts ofall submarine operating nations to producethe desired effects. The NATO countries thatsincerely want to extend the assets and expertise too the r na t i ons on human i ta r i an g rounds a reundertaking effort ofevery kind in this respect. TheSMERWG provides the mechanism for renderingt imely assis tance and advice in the event of asubmarine disaster. The proficiency developed rnrespect of SMER could be effectively utilised by acountry l ike India, which has l imited resources inthis field but has a number of submarines in hernaval inventory. As the submar ine d isasterscontinue to happen each year it is essential that allsubmarine operating nations cooperate and providemutual support to minimise the time to first rescue.In order to harness the resources available the rVorldover, there is also a need to standardise onboardequipment and procedures related to SMER.
105
PRESENT DAY CONCEFTS IN MANAGEMENT OF CRANIO MAXIL-LOFACIAL TRAUMA
Surg Cmde @) Sushanta Karkun*, SurgLt Cdr(D) KMajumder+
Abstract
The overview at tempts to study the histor ical review classi f icat ion management and compl icat ion re lated toCranio maxillofacial Gun shot wounds, road traffic accidents fall from heights etc. The profile also indicatesthe modern technical advancement and hol is t ic approach in funct ional stabi l i ty and rehabi l i tat ion of thevict ims. Maxi l lofacia l surgeons play an importnat ro le in stabl izat ion of var ied nature of gunshot wounds/bal l is t ic in jur ies involv ing the cranio maxi l lofacia l region. With the adveDt of technologies, modern surgeonare well equipped to manage with a holistic approach such problems.
Key Words : Cranio maxi l lofacia l t rauma, Advanced bio-management .
INTRODUCTION
Qince the discovery of science and technology,lJthe human mind activated through the ages fordevelopment of varied nature skills for managementof gunshot wound/trauma victims. The products ofsuch injuries are loss of l i fe and limb. Variousspecialities are called to save many a life and limb.The facial wounds oftern are very aggressive anddeformed in nature. Maxillofacial surgeons play animportant role in stabilzation and rehabil itation ofdifferent types of gunshots wounds/trauma victmsinvolving the cranio maxil lofacial region. In timelycare and resuscitation the functional and aestheticrecovery of such cases may provide desired results.Both civil and military aggression and road trafficaccidents involve the clinicians in management offacio maxil lary injuries. The outcome of suchincidences has resulted in active biological researchfor improvement of techniques and materials.
HISTORICALREVIEW
The distinctive features of injuries associatedlrith explosives have been recognized since theinven t i on o f gunpowder . t he g ross oedema,discolouration and susceptibil i ty to infection werein the past attributed to the poisonous character ofthe gunpowder itself. Many of the previous studieson missile injuries paid scant attention to ball istics
and yet it is this science which is fundamental inunderstanding the characteristic of a particular injuryand the subsequent treatment.
A quote from Ambroise Pare, Cing Livres dechirurgie (1952) [I6] states "A germane ofobscurebirth and condition, who demonstrated the use ofgunpowder to the Venetians when they watted withthe Genoveses about Fossa Claudia, in the year ofour Lord 1380. I think that the deviser ofthe deadlyEngeine hath this for his recompense, that his nameshould be hidden by the darkness if perpetualignorancem as not mer i t ing for th is , h is mostpernicious invention, any mention from posterity".
Various literature has also quoted the clinicaldescription of ballistic wounds noted by cliniciansof the medieval period. A note by the surgeons toKing Chales II discussed in detail a classic clinicalcase of Gun Shot injuries infected on a militaryofficer. '
History dates back use of the first Artillery smallarms called jHand Canons' in late l3th century [2]followed by 'Fire Locks' in the l4th century. ln l5thcentury [4]
'Muskets'came into use. The Japeneseintroduced a very heavy type of musket. This wasfollowed by a 'Wheel lock' sometime in 1515.
Further improvement between lTth to early l9thcentury developed wide range of 'Canons'
I l]
'Director & Dental Advisor (Navy); *Graded Specialist (Oral & Maxillary Surgery); Naval Institute of Dental Sciences, INHS
Asvini Campus, Colaba, Mumbai 400 005.
Jour Marine Medical Society, 2007, Vol.9, No.2106
{T'Shoulder' and 'Hand Guns', Non-jacketed bullets'
I I I ] which caused massive biological injuries wereused dur ing those days were la ter banned byinternational agreements and replaced with JacketedBullets. Improved Automatic Weapons, Mortars,Grenadesm, Missile, etc which resulted in long rangerapid active fire and devastating injuries came intouse since the 20th century.Rob, quoted by Porritt(1953), analysed the overall frequency of secondworld war wounds by various missiles as follows
l16 l "
a) Fragmentation missiles (mortar, aerial bomb,grenade shells)
b) Solid missiles (bullets, anti-tank shells)
c) Land mines, booby traps
d) Blast crush
e) Chemical(phosphrous)
0 Other wounds
CLASSIFICATION OF INJURIES
The wounding characteristic of various missiles:DeMuth (1966, 1969) [6] and DeMuth and Smith( 1966) [7] have done much to clarify the woundingabil ity of various missiles. It is generallv acceptedthat the capacity to injure depends on the Kineticenergy (KE) at impact. According to the formula KE= t/z Mass x Velocity it can be appreciated thatterminal velocity is relatively more important thanmass in determining the energy dispersed at the pointof impact.
Bullet velocity is classified as low, under 1000feet/s; medium, between 1000 and 2000 feet/s andhigh, above 3000 feeVs. It is, however, the impactvelocity which is the most important determinant ofwounding capacity. Abullet requires a certain massbecause offactors such as accuracy, projectory andmaintenance of velocity. Its shape is crucial rnovercoming air - resistance in fl ight. The ratiobetween bullet weight and area of presentation iscalled the sectional density. This value is importantin determin ing what is known as the bal l is t iccoefficient. In simple terms, the higher the ball isticcoefficient, the less the velocity loss per 100 yardsof f l ight and thus the greater the velocity of impactand killing power.
a) Penetrating Wounds : These are wounds
Jour Marine Medical Society, 2007, VoL9, No.2
caused by missiles of low impact velocity inwhich a small point of entry is found with them iss i l e embedded i n t he t i s sue . A l t houghusually minor at the time, the proximity of thefragment or bullet to a vital structure such as amajor blood vessel may be important. Rush ofair and contaminants into the cavity behind themissile in evident accounts for the dirtness ofgunshot wounds. Rapid sealing of the softt issues at the points ofentry and exit is a resultof t issue recoil. Inegular walls of the cavityassociated with splitting of the muscle fibers,the pressure effects within the tissues suggests,tissue damage which is intensive beyond thevisible track of the missile. This combination oftissue death and contamination is of courseh igh l y f avou rab le t o bac te r i a l i n fec t i onparticularly by anaerobes.
Perforating Wounds : Missile of high velocitypass right through the tissues with entranceand exit wounds. In general, exits wounds arelarger than the entrance wounds which maysomet imes be healed before the casual tyreaches effective hospital treatment (Awty andBanks l97l ) [ l ] (F igdegreeof spn) . In modernwarefare such a wound can also be caused bythe rup tu re o f a l a rge tempora ry cav i t yproduced by a small ultra-high-velocity bullet.The crucial f'actor in cavity production is thespecific gravity of the tissue and dense corticalbone is , in consequence, the most sever lydamaged of any of the body tissues (DeMuth& Smith I966). When a bullet strikes bone, thekinetic energy is expended and transferred tofragments which act as secondary missiles ofmuch lower veloc i ty . The wound may besuperficial ly indigtinguishable from short rangeinjury from a shotgun. In rare instance, humaninjury caused by expanding bullets may be seenas a resu l t o f spo r t i ng acc iden ts , su i c i deattempts or homicidal act.
It is impossible, as shown previously, to knowthe extent of injury unless the impact velocityof the missile can. be estimated [7] as withoutth is knowledge the extent of av iat ions isindeterminant. In other words, two perforatingwounds of similar appearance may behave quite
mospherer r i g i na ted:rat ion onCependen tortablc in,urning ofSoda l i rneCO. . I I i ghenerat iou.i on o f t hei c r sys temvai labi l i t l 'cand l c t oi n such a
generat ionbe r . A l t e r;ubmarine .on and O ,)or table in
s gen lngreings and: effect ofr gases thers evolvedbmarine inically inertrvhich arenoLpose a,n board a
ration in aval of CO,.:cial f i l ters
re taken as
\ /o1.9. No.2
b)
107
differently. In one, early closure may be followedby primary healing whereas, in the other, closurewithout appropriate debridement and drainagemay be catastrophic owing to the extent ofdevitalized tissue along the wound tract [8].
c) Avulsive Wounds : Massive wounds withavulsion and loss of t issue can be produced bya variety of weapons. Injuries of this type werecommonly attributed, in the first and secondworld Wars, to large irregular fragments ofbombs shell, mines or grenades travell ing atmedium velocity with various. It is more usefulin considering missile injuries of the head andneck to group them according to the site anddirection of impact. Injuries that directly involvethe c ran ia l cav i t y . F ron to -NasoE thmo id ,Nasotorb i to - maxi l lary complex [8] aredevastating, l i t 'e threatening and subsequentlyleave behind residual deformities.
It is also apparent that some wounds will involvebone and some wi l l not , and some wi l l beassociated with soft-t issue loss making anyformal classification most difficult. There areno large muscle masses in which the effects ofcavitations are so damaging. The blood supplyof the area is abundant, allowing some wellfounded surgical principles to be transgressedwith relative impunity, since antibiotics becameavailable the risk ofsecondary hemarrohage. Itis, therefore, more often possible to effect.Primary closure of maxillofacial wounds thanthose in other parts ofthe body (Clarkson et al1946)141. Broadbent & Woolf 1972, [3] advocatethe use of skin flaps and even bone grating aspart of the pr imary t reatment . F inal ly , thetremendous problem of circulatory collapserequiring massive blood replacement (Coppelet al)[5] is less of a factor in maxil lofacialwounds , as ev idenced i n t he reco rdedexperience of forward maxillofacial units in thesecond World War. The particular dangers tolife from these wounds arise chiefly frominvo l vemen t o f t he c ran ia l cav i t y , ea r l yobstruction of the airway, or damage to largeblood vessels in the neck. A part from loss ofl ife, the most serious consequence of injury isdamage to special senses, particularly eyesight
t08
and to a lesser degree, hearing and smell.
MANAGEMENT
Primary Care
The management of the acutely injured craniomaxil lofacial ball istic patient is not l imited to therecognition of injuries and operative care. Care ofthe trauma patient includes the problems of shock,fluid resuscitation, nutrit ional supplementationcorrect ion of e lect ro ly te imbalance and otherproblems related to tiding over the acute crisis [6].The trauma surgeon becomes the primary carephysic ian for the ser iously in jured indiv idual .Maxillofacial trauma occur in a wide spectrum ofseverity an effects of ages, soft tissue injuries ofthe face can be easily managed by any surgeon.More complex injuries will require the combined efforto f o the r consu l t an t s i n Neu ro su rge ry ,Ophthalmology, Otorh inolaryngology, Plast icsurgery and Oral surgery. Primary survey whichconsists of the assessment of air way, breathingand circulatuin is of paramount importance. Thedetailed assessment of maxil lofacial injuries wil lconstitute the secondary survey.
a) Initial resuscitation : The inability to provideoxygenated blood to the brain and other vitalstructures is the quickest killer of the injured
[6] . Presentat ion of hypoxemia requi res aprotected unobstructed airway and adequateventilation that must take priority over all otherconditions. An airway must be secured, oxygendelivered, and ventilator support provided.Supplemental oxygen must be administered toall trauma patients.
b) Airway : Securing an adequate airway in thefirst and the most important step. The throathas to be inspected for blood clots and theyhave to be mechanically removed. The chin l iftand jaw thrust manoeuvres are usefu l inclearing the airway. At this point one shouldensure that there is no spine in jury. I f anendotracheal in tubat ion is necessary th ispossibility has to be borne in mind, for, theef fects of an in judic ious morover can bedevastating. However, if there is any doubtregarding the airway, endotracheal intubatroncan be done after stabil izing the cervical sprne.
Jour Marine Medical Society, 2007, VoL9, No.2
smel l .
ured cranionited to theare. Care ofns of shock,ementatronand other
te crisis [61.' imary careind i v i dua l .ipectrum of: injuries ofry surgeon.nbined ef'fortI su rge ry .gy , P las t i crvey whichr, breathingrtance. Thenjuries wil l
y to provideI other vitalthe injuredrequrres a
rd adequatever all otherred, oxygent provided.rinistered to
rway in theThe throat
ts and theyfhe chin l ift: usefu l inone shouldjury. If an:ssary th isnd, for, therer can beany doubtintubation
vical spine.
, Vol.9, No. 2
Trauma to the face is a setting that may demandaggressive airway management. Trauma to themidface may produce fractures - disclocations withcompromise to the nasopharynx and oropharynx [5].Facial fractures may be associated with hemorrhage,increased secretion and dislodged teeth, causingadditional problems in maintaining a patent airwaymuscle support and inability to protrude the tongue.airway obstruction will result if the patient is in asupine position. If the soft tissue and bones of themidface are not involved. nasotracheal intubationand orotracheal intubation in case of such injuriesshould be done. Crithyroidectomy is now thepreferred emergency procedure. Classictracheostomy is now confined to select patients withlaryngeal injuries.
c) Breathing : If breathing is inadequate eitherdue to a chest injury or decreased respiratorydrive due to a head injury, venti latory supportmay be necessary. Haemothorax, pneumothoraxand misplaced endotracheal tubes are the maincauses of inef fect ive vent i la t ion. Cl in ica lexamination of the chest and if possible a chestx-ray in the erect position can provide reliableinformation about abnormalities.
d) Circulation : The most extreme example ofhemorrhage is the patient in cardiac amest fromhypovolemia [6]. In such an instance, the onlychance for salvage is immediate emergencythracotomy and open chest cardiac massage.Haemostasis should be achieved first wheneverpossible especially in the extermities. A widebore cannula should be introduced into the veinof the arm or groin for fluid replacement. Bloodmade available for transfusion if an d whenrequired.
Haemonhage is the most important cause of postinjury deaths that are amenable to effective and rapidt reatment in the hospi ta l set t ing. Hypotensionfo l l ow ing i n j u r y mus t be cons ide red to behypovolemic in origin until proved oherwise. Rapidand accurate assessment of the injured patients'haemodynamic status is therefore essential. Twoelements of observation yield key information withinseconds - level of consciousness and pulse. Skincolour can be helpful in evaluating the hypovolemicinjured patient. A patient with pink skin, especially
Jour Marine Medical Society, 2007, Vol.9, No.2
in the face and extremit ies, is rare ly cr i t ica lhypovolemic agter injury. Conversely the ashen grayskin of the face and the whi te sk in of theexsanguinated extremities are omnious signs ofhypovolemia. These latter signs usually indicate ablood volume loss of at least 307o, if hypovolemia isthe cause [5].
e) Indices ofsuccessful Resuscitation [6]1. Adequate peripheral perfusion capillary refill
in nail beds I sec)
2. Level of consciousness (alert, oriented innon-head injuries)
3. Blood pressure (100 systolic)
4. Urine output (0.5 cclkg/hr)
5. Atrial filling pressures (keep between 3-8Ton)
6. Neurological Assessment
Further assessment should include a notation ofall lacerations, abrasions ecchymoses and externalstigmata of trauma. simple sketches can be made ofwounds in the init ial record. Significant bleedingcan lead to shock if not taken care of as early aspossible.
Examination of the eye consists of pupil size,shape , symmet ry and reac t i on t o pen to rchexamination. Blood in the anterior chamber and ared retinal reflex and fundoscopic examinationshould be checked and ophthalmologv consultationsought.
Nasal fractures are very common and discoveredo n p h y s i c a l e x a m i n a t i o n b y i n s t a b i l i t y a n dcrepitations on palpation ofthe nasal bridge. Signsof inflammation may be present. A nasal septalhaematoma can result in damage to the cartilage.
CSF leak through the nose indicates a cribriformplate injury with a dual tear. CSF otorrhoea can beidentified by the two rings that blood collected in awhite handkerchief produces [ 18].
Intermediate Care
Subsequent to care and resuscitation of soft andhard tissue wounds, secondary or intermediatecomposite care is mandatory as early as possible foref fect ive funct ional and aesthet ic resul ts . Thefollowing general factors are important consideration
109
for better healing of the composite wounds.
a) Diet and feeding : Where jaw fracture hasoccured a normal liquid jaw diet regime will beemployed and patients with war wounds do notdiffer from civilian maxillofacial injuries in thisrespect. It should however be remembered thatthese patients have often sustained more bloodloss than civilian injuries and are frequentlymore gene ra l l y deb i l i t a ted . Ca l cu la tedmaintenance of 1600 k/cal to 2000 k/cal ofenergyshould be aimed for the modified diet chart.
b) OraI Hygiene : A sodium perborate mouthwash(Bocasan) is a most effective solution for post-operative use in jaw injuries, In addition activeinigation of the oral cavity with a four per centsolution active inigation of sodium bicarbonateshould be carr ied out at least once dai ly .Addition of a flavoured antiseptic mouth washwill be effective.
c) Control of infection : Inspite of measures taketo control, initial wound infection invasion byother resistant organisms may occur. Systemicinfect ion may supervene but , in general ,favourable local factors in the facial region makesystemic spread uncommon. The possib lesequelae which can resul t f rom bacter ia linvasion may be summarised as follow :
i) Systemic
Septicaemia
Pulmonary
Meningeal
Thrombophelebitis
ii) Local
Secondary Care
After pirmary healing of the wound has occuredand infection has been culminated, many patientswith missile injuries are left with residual deficiencyof bone or soft tissue. It is much more difficult torestore function and appearance in the secondaryphase. For this reason every effort is made tominimize the residual defect during the initial surgicalmanagement. The problem of oro fac ia lreconstruction is a subject in itself and only a briefsummary will be attempted here. In general, the tasksof reconstruction which mav be encountered can be
110
categorised :
i) loss of specialised organs and tissues whichcannot be replaced
iD loss ofspecialised tissue whose function cannotbe fully restored
iiD Loss of less specialised soft tissue
iv) Loss of bone
Definitive surgical planning are instituted at thisstage for composite repair and stabilzation. Use ofmicro/mini/reconstruction plates and screw implantsis an active part in the armamentatrium of the faciomaxillary surgeon I l0]. Loss of part of upper/lowerjaw bone [2] or other craniofacial bone can alsoaptly be substituted by autogenous bone grafts I I 3]i l iac crest, Ribs radices, t ibia or f ibula may beprobable donor sites. Microvascular surgeries [91may be opted tbr bone loss replacement with muchmore better acceptability. Distraction osteogenesis
[7] may also be planned specially in those case ofbone loss without compromised enveloping softt issue specially involving the lower jaw.
Tertiary Care
Residual defects funct ional and aesthet iccomplications are considered at this stage. Theclassic guidelines of the deformities are based onreplacement of matching b io logical t issue orprosthesis :
D a) Soft tissue defects
Local flaps
Distant flaps
Myocutaneous flaps
Free flaps
b) Repairs of fistulas
c) Micro lepair of degenerated nerve fibers
ii) Prosthesis : Replacement of those residualdefects which cannot be replaced by the abovetechniques/biological materials are edifined byprosthet ic mater ia ls for some funct ional /aesthetics resemblance of vital organs l ikeMedpore, Tefleon, medical grade silastics etc.
a) Eye
b) Ear
c) Nose
Jour. Marine Medical Society,2007, Vol.9, No.2
d) DentoAlveolarimplants
e) Maxillofacialprosthesis
RETERENCES
l. Awty Md, Banks P, Klamb WT. Review of the treatrnentof facial injuries in the Nigerian Civil War. Tlansactionof the forth international conference in oral surgery,Compnhage : Munksgaard 1973; pp 291-3.
2. Bradley, Joseph. Glues of the Tsam, Northern Illianos,University Press, History of Russian Small Arunlndustry,1990.
3. BroadbentTR, Woolf RM.Gunshot wounds of the face:initial care. Journal of Trauma 1972 12 : 229.
4. Clarkson P, Wilson THH, Lawrie RS. Treatment ofJaw and face casualties in the British Armv. Annals ofSurge.ry 123: l9O.
5. Coppel DL, Batmer, HGR, Dundee JW. Civil disturbanceand anaesthetic workload in the Royal Victoria HospitalBelfast : The respiratory and intensive care unit.Anaestlrcsia and Analgesia 1973; 52 : 147.
6. Culas TB. Trauma Care - An overview Part ll. IndianJournal of Oral & Maxilofacial Surgery 1998; XIII :5 -9 .
7. DeMuth WE. High Velocity and desigi as determinants
. of wounding capability : an experience stldy. Journalof Trauma 1966; 6: 222.
8. De Muth WE, Smith JM. High velociry bullet wounds
of muscle and bone, the abasis of rat ional earlytreatment. Journal o.f Trauma 1966: 6 : 744.
Donnoff RB, May JW. Micro vascular mandibufarreconstruction. Journal of Oral Maxillofacial Surgery1982;40 : 122.
Gutman D. Mandibular bone graft ing in trauma.International Journal of OraI Surgery 1972; | : 103.
Hartnik AE. Encyclopedia of pistols and Revolvers,Knick bocker. A Comprehensive guide. 1997.
Mclndoe AH. Surgical and dental Featrhent of fracturesof the upper and lowerjaw in war time. Proceedings oftlu Royal Society of Medicine l94l;34 : 267.
Mohnac AM. Gross loss of mandibular hard strrcture.Journal of OraI Surgery 1979',27 : 508.
Oakeshott, Evart R. The Archaeopogy of weapons.Boydell and Brewer. History of weapons from thebronze Age to the medieval period.
Osbon DB. Intermediate and reconstructive care ofmaxillofacial missile wounds. Journal of Oral Surgeryl9't3; 3l : 429.
Rowe NL, Wil l iams. Maxilofacial Iniuries Vol. I I :56r -67 .
Samchukov ML, Cope JB, Cherkashin AM. CraniofacialDistraction Osteogenesis, MOSBY, 20Ol; 349.
Stranc MF. The pattem of lachrymal injuries in naso-ethmoid fractures. Britislr Journal of Plastic Surgery1970:.23 : 4.
10 .
I l .
12.
1 3 .
1 4 .
t 5 .
1 6 .
r7 .
t 8 .
Jour Marhc Medical Society,2007, Vol.9, No.2 il1
DEPRESSION AND ITS RELATION TO CORONARY ARTERYDISEASE
Surg CdrA T[ipathi-, Surg Capt AA Pawar**, Ms P Kalyankar--', Surg Cdr NK Mahesh*,Surg Cdr KKMishra*, Ms J Rathod*
ABSTRACT
The present study investigated the relation between Depression and Coronary Artery Disease (CAD). The studyalso investigated the correlat ion between depression in CAD and the variables of smoking, hypertension anddiabetes, A sample of 56 male cases in the age group of 25 to 60 years of CAD diagnosed by angiography wasselected. The socio demographic proforma, the Beck's Depression Inventory (BDI) and Presumptive Life EventsScale (PSLE) were used. The results revealed that in the total sample, 20Va of people suffered from Depression,Highest number of people fell in the range of mild to moderate depression. The highest number of item (44Vo)endorsed on the BDI was that of 'tiredness or fatigue'. There. was no significant corrclation between depressedpatients with CAD with smoking, hypertension and diabetes. Analysis of PSLE also showed no signif icantcorrelat ion between depression and any of the l i fe events,
Key Words : Coronary artery disease, Depression, Myocardial infarct ion
INTRODUCTION
/'^toronary artery disease and Depression are\-,growing problems in today's era. The WorldHealth Organisation has predicted that these twodiseases will account for the greatest degree of mor-bidity and mortality in the coming decade. Thenational comorbidity survey showed that the l ife-time prevalence of Major Depression was l7. I 7o I I ],which is similar to the fact that one in five person inthe United States have some form of cardiovasculardisease. In such a scenario extensive comorbidity isto be expected, however, the relationship is morethat mere coincidence as there is ample evidencetha t dep ress i ve symp toms and a h i s to ry o fdepression are strong independent risk factors forthe development of cardiovascular disease, acutecoronary events and mortality from cardiac illness
[2]. The incidence of depression in CAD is in theregion of l5-22o/o, [3] though older studies havereported higher figures.
Depression following CAD has been associatedwith 3 to 8 fold increase in cardiac death for as longas 5 years after myocardial infarction, a 2to 4 foldincrease in arrhythmic events. In Canada it has been
recommended by the Canadian Cardiovascularsociety that all patients with acute MI be screenedfor depression [4]. The recognition ofdepression lscrucial as not only do depressed patients experiencegreat difficulties in problem solving and coping withcha l l enges , bu t dep ress ion adve rse l y a f f ec t scompliance with medical therapy and rehabil itationand increases medical co morbidity [51.
Our observat ional s tudy a imed to s tudy there lat ionship of depression and eoronary ar terydisease.
METHODS
The sample comprise of 56 patients of CoronaryArtery Disease who were attending the CardiologyOPD of a service hospital. The study included malepatients who had undergone coronary angiographyin the preceding fortnight and had angiographicevidence of the coronary artery diseaSe and whowere in the age group of20-60 years. Excluded fromthe study were patients of myocardial infarction.ventricular failure, cerebro-vascular disorders,demen t i a , psycho t i c d i so rde rs , subs tancedependence and chronic i l lnesses with physical or
'C lassi f ied Spl Psychiatry; "Sr Adr Psychiatry; " 'Cl in ical Psychologist : tClassi f ied Spel . Medic ine & Cardio logy, INHS
Kalyani; *Classified Spl Psychiatry; **Medical Social Worker.
Jour Marine Medical Society, 2007, Vol.9, No.2112
mental complications.
Sociodemographic data and risk factors for CADwere obtained through interview and all patientsunder went assessment by a psychiatrist. The 2litem Beck Depression Inventory-Il (BDI-ID was usedto measure depressive symptoms and thePresumptive Sressful Life Events (PSLE) which is a5 I item adaptation of the Holmes and Rahe scale forIndian population was used to measure stressfullife events.
RESULTS
Table I shows the characteristics of the studygroup. The present study included only males andfemales were excluded due to limitation of thehospital.
Table 2 shows that 207o of the patients sufferedfrom depression. It further shows that of these L3Voof patients had mild to moderate depression, 27o of
TABLE 1Characteristics of the study group
Variables Number %
the patients had moderate to severe range and 5Voof patients had extremely severe depression as perthe BDI rating scale. The remaining 45Vo patientshad minimal mood disturbance.
Table 3 reveals that the highest item endorsed bythe group on the BDI was that of 'tiredness orfatigue' (45Vo), followed by 'loss of interest in sex'(36Vo). The items of initability' and 'concentration
difficulty' were marked equally (30Vo),followed byitems of 'changes in the sleeping pattern' and 'self
critical nes s' (29 Vo each).
Table 4 shows no s igni f icant re lat ionship
TABLE 2BDI-II score of the study group
Score Range No. of people
0 - 1 3l4-1920-2829-62
Minimal mood disturbance 45 (8O%)
Mild to moderate depression 07 (13%)
Moderate to severe depression 01 (ZVo)
Extremely severe depression 03 (5Vo)
TABLE 3
Endorsment of items on BDI-IIAge (years)
20-40
4t-60
Duration of illness (years)
0 m o n t h s - 2 y e a r s
2 . l y e a r s - 4 y e a r s
4 . l y e a r s - 6 y e a r s
6 . l y e a r s - 8 y e a r s
Family history
Present
Absent
Smoking history
Present
Absent
Blood pressure
Hypertensive
Normotensive
Glycemic status
Diabetic
Non Diabetic
B M I
< 2 5
> 2 5
t 244
2 220t 202
065 0
24) z
l 5
4 l
l 0
4 6
2 2
3 4
2 l7 9
3 93 62 l04
l l
8 9
4 3
) l
27t )
l 8
8 2
3 9
6 1
Items Depression Frequency
l. Sadness2. Pessimism3. Past failure4. Loss of pleasure5. Guilty feelings6. Punishment feelings7. Self-dislike8. Self-criticalness9. Suicidal thoughts or wishes10. CryingI l . Agitat ion12. Loss of interestI 3. Indecisiveness14. Worthlessness15. Loss of energy16. Changes in sleeping pattern17. Irr i tabi l i ty18. Changes in appetite19. Concentrat ion dif f iculty20. Tiredness or fatigue21. Loss of interest in sex
09 ( l6Vo)
08 (22Vo)
08 (22%)
0 7 ( 1 3 % )
04 (O77o)
07 ( l3Vo)
08 (227o)
16 (29Vo\
01 (02Vo)
03 (05Vo)t l (20Vo)
05 (09Vo)
08 (22Vo)
0 6 ( r l V o )
15 (27Vo)
16 (29Vo)l7 (30Vo)
13 (23Vo\17 (30V0)25 (44Vo)20 (36Vo)
Jour Marine Medical Society, 2(N7, Vol.9, No.2 1 t 3
TABLE 4
Relationship of depression in CAD with other risk factors
Risk factors Depressed Not depressed Chi square P value
Smoking
Smoker
Non smoker
Blood Pressure
Hypertension
Non hypertension
Diabetes
Diabet ic
Non diabetic
5
6
6
J
6
l 9
2 6
l 0
J )
7
3 8
0 .02 r
1 .392
0.221
0.884 NS
0.238 NS
0.638 NS
between depression and CAD risk factors ofsmoking, hypertension and diabetes.
The mean numbers of s t ressfu l l i fe eventsendorsed by CAD patients were similar in bothdepressed and non depressed groups as shown inTable 5.
DISCUSSION
The association with various mood states andheart disease has been known for a long time. Theearlier data has been difficult to interpret due to avar iety of reasons such as lack of consis tentdefinition, medical co-morbidities, different tests ofpsychiatric assessment and their applicabil ity isquestionable today [6]. Studies show a bidirectionall inkage between depression and cardiovasculardisease.
The present study shows that2o%o of the patientshad co morbid depression. This prevalence is similarto Carney et al [7] who studied 52 patients withangiographic findings of coronary artery diseaseand found that just less than207o met the criteria formajor depression and that this group was more likelyto develop adverse cardiac complications over thenext year. Frasure-Smith [8] showed that 167o of thosehospitalized with a myocardial infarction haddepression and that at 6 months they had a lTVomortality, compared to 3Vo in the non depressedgroup.
Our study uses a score of 14 and above toclassify depression on the BDL Frasure-Smith [9]has showed that patient with scores even below l0
I t4
Past I year (mean) Li fe t ime (mean)
Depressed
Non depressed
5
2t 4
t 2
on the BDI may experience similar risk to those withhigher that l9 scores. It has been argued thatdistinction on severity of depression may not beimportant and that var iat ion in the degree ofdepression only represents fluctuation with time inthe same chronic i l lness.
The most frequently endorsed item on the BDIwere tiredness (44Vo) and loss of interest in sex (337o)which may be contributory to the missed diagnosisof depression in CAD patients. There were followedby self critic alness (29 Vo), d iffic u I ty concentrati n g(30Vo) and changes in sleep. Brutsaert et al [0Jshowed in their study that reducing emotionaldistress may improve prognosis in coronary heartdisease (CHD).
As far as risk factors ofcoronary artery diseaseare concerned, i.e. smoking, hypertension anddiabetes this study did not show any statisticaldifferences between those patients of coronaryartery disease who were depressed and those whowere not. It is a well known fact that depression isassociated with increased rates of smoking anddiabetes [2], increased norephinermine secretion andhypertension [5] and that since these risk factors
Jour Marine Medical Society, 2N7, Vol.9, No. 2
TABLE 5
Distr ibution of PSLE items in CAD patients
are also associated with CAD there was nosignificant difference between the two groups. ThePLSE was also similar in both depressed and nondepressed patients with CAD.
CONCLUSION
Depression and subsyndromal depressionantedate symptoms of CAD by decades in westerncountries and possibly by a similar number of yearsin our country. It is well known that depression isassociated with a increased risk of developing CADand increased relative risk of cardiac mortalityfollowing a cardiac event. However, though it seemslogical that treatment of depression after amyocardial infarction would lower that risk; it is alsoa well known fact that the tricyclic drugs affectmyocardial conduction and that there is l i tt leevidence that SSRI's are useful in reducing thismortality. It possibly would be more effective toscreen and treat depression and sub depressivesyndrome especially in person who have risk factorsof CAD rather than to wait for a cardiac event. Itmust be recommended that depression is an illnesswhich is a risk factor for many physical illnesses,including CAD and early intervention couldpossibly lead to better outcome.
RETERENCES
l. Blazer DG Kessler RC, Mc Gonagle KA, et al. Theprevalence and distribution of Major Depression in aNational Community Sample : The National Comorbidity Survey. Am J Psychiatry 1994; l5l :979-86.
Joun Marine Medical Society, 2N7, Vol.9, No.2
Schulman JR, Muskin PR, Shapiro PA. Psychiatry andCardiovascular Disease. Focus 2005; lll (2):208-24.
Guck TB Kavan MG Elasser GN, et al. Assessmentand treatment of depression fol lowing myocardialin fa rc t ion . Am Fami ly Phys ic ian 2001; 64 (4 ) :6 4 1 - 8 .
Lauzon C, Dupuis R, Beck CA, et al. Depression andprognosis following hospital admission because ofacute myocardial infarct ion. Canadian MedicalAssociation Journal 2003; 168 (5) : 547-52.
Musselman DL, Evans DL, Nemeroff CB. Therelationship of depression to cardiovascular disease :Epidemiology, Biology and treatment. Arch GenPsychiatry 19981 55 : 580-92.
lanuzzi lL, Stem TA, Pasternal RC, et al. The influenceof anxiety and depression on the outcome of patientwith coronary artery disease. Arch Intern Med 2000;1 6 0 : l 9 l 3 - 2 1 .
Carney RM, Rich MW Freedland KE, et al. Majordepressive disorder predicts cardiac events in patientswith coronary artery disease. Psychosom Med 1988;5O : 627-33.
Frasure-Smith N, Lesperance F, Talajic M. Depressionfollowing a myocardial infarction : impact on 6 monthsurvival. JAMA 1993: 270 : l8l9-25.
Frasure -Smith N, Lesperance F. Depression and otherpsychological risks following myocardial infarction.Arch Gen Psychiatry 2003; 60 :627-36.
Denollet J, Brutsaert DL. Reducing emotional distressimproves prognosis in coronary heart disease : 9 year
mortality in a clinical trial rehabilitation. Circulation2001; 104 : 2018-33.
4 .
{
8 .
9 .
1 0 .
I I 5
OPTIMIZING GLYCEMIC CONTROL AND ACHIEVING GLYCEMICTARGETS IN AN ARMED FORCES SETUP
Surg CdrVivek Kumar", Surg CaptAshok Bhagra*
ABSTRACT
Aim : To study an innovative approach aimed at increasing the percentage of diabetics achieving glycemictargets in an Armed Forces Medical setup where cost of therapy is borne by the Government.
Material and Method : 500 diabetics (Type 2) were followed up from Sept. 05 to May 06. Those with sub optimalglycemic control {FPG > 130 mg%o and/or PPPG 2 180 mgTo) at basel ine (visi t 1) were counseled and theirtherapy optimized over next 3 months before assessment at day 90 (visit 2); those with sub optimal control werethen assessed at 10 day intervals (day 100 = visit 3, day 110 = visit 4 and day 120 = visit 5) after which they werehospital ized (maximum 10 days). Those achieving optimal control at any stage were fol lowed up monthly.
Results :9,47o (471500) and optimal glycemic control at basel ine (visi t l ) . Of those with sub optimal controln=453; ll.SVo (521453) achieved glycemic targets by day 90/visit 2, an additional 2,5Vo (f0/40f) by day 100/visit 3,3.65o (141384) by day 110/visit 4,13.44o (481357) by day 120/visit 5 and 62.5Ea (1851296) following hospitalization.Overall the percentage diabetics achieving glycemic targets increased from 9,4Vo (4715001 at baseline to 78Vo(309/396) at completion with maximum increase during hospitalization. l2.6Co (571453) cases dropped out, mostat time of admission. Factors responsible for improved glycemic control were: correction of dietary indiscretion574o and, sedentary lifestyle 73Va, optimization of therapy l4vo witln significant overlap between the groups.97Eo (3001309) patients sustained the glycemic targets achieved during a further 90 day follow up. There wasalso an improvement in other therapeutic targets: Ideal body weight + ll%o (44.8 )79Vo), LDL cholesterol < 100mg%o (22.2 +48.7Vo) and blood pressure <130/80 mmHg (43.4 )El,64o).
Conclusion : Frequent targeted OPD fol low-ups of diabetics and i f required a short period of hospital izat iongreatly increased percentage of those achieving glycemic and associated therapeutic targets in our set-upwhere cost of therapy is borne by Government. This is expected to markedly reduce disease burden andtreatment costs. We recommend this approach for other Government/Corporate/Insurance paid s€t-ups.
Key Words : Diabetes, Glycemic targets
BACKGROUND
Jn an Armed Forces hospital the government paysIfor the cost of therapy. Type 2 Diabetes Mellitusis increasing in incidence in India and is predictedto assume epidemic proportions soon []. Treatmentfor Type 2 DM is costly, lifelong, and effective onlyif the therapeutic targets are met. Sub optimalglycemic control perpetuates disease progressionand development of complications [2,3,4]. Treatmentof complications is costl ier causing a heavier ex-penditure from government funds [5,6].
During our follow-up of diabetic patients we notedthat treatment targets were not being achieved rnmost cases. We felt that patients were not complyingwith lifestyle modification instructions and were not
paying much attention to their i l lness, probablybecause medication was free. We felt that morefrequent follow-ups and ifrequired a short period ofhospitalization would probably help solve this issue.
AJM
To study an innovative approach designed toincrease the proport ion of pat ients achiev ingglycemic targets in an Armed Forces medical setup,thereby benefit ing the patient and saving moneyfor the government.
METHODS
The study was conducted in an Armed ForcesHospital. 27,540patients were seen in Medical OPD
'C lassi f ied Special is t Medic ine. INHS Kalyani , Vishakhapatnam. *Senior Advisor Medic ine, INHS Sanj ivani , Cochin.
116 Jour Marine Medical Societv, 2007, V'o\.9. No. 2
ofour hospital between 0l Jan. - 3 I Dec. 2005.6664(24.2Vo) of these were diabetic follow-ups averagingto 555 diabetics per month. 500 diabetics wereenrolled and followed up as subjects for studybetween September 2005 to May 2006. All of thesepatients had Type 2 Diabetes. 316 (63.2Vo) patientswere on insulin as monotherapy or combinationtherapy. As per provisions in our system, at everyvisit patients were provided with medicines for 30days. Blood glucose (BG) was checked monthly ifcontrol was sub optimal and 3-monthly if controlwas optimal.
Optimal glycemic control was defined as a fastingplasma glucose (FPG) of < 130 mgTo and 2-hourPostPrandial plasma glucose (PPPG) of < I 80 mgVo l7l.During the first visit (visit 1) we assessed thebaseline glycemic status defined as the average valueof last three blood glucose readings. 453 (90.67o)Diabetics had sub optimal glycemic control (FPG> 130 mg%o and/or PPPG > | 8O mgTo). Diabetics wi thsub optimal glycemic control were identified andrepeatedly counseled to improve l i festy lemodification and their diabetic medication wasoptimized over the subsequent three months. 90days after their f irst visit the BG values werereassessed (visit 2). Those with optimal BG controlwere continued on monthly follow-ups while thosewith sub optimal control were put on a l0 day followup with re-emphasis on lifestyle modification andadjustment of drug therapy. On day 100 (visit 3) ifglycemic control was sub optimal the patient wasgiven another l0 days to optimize his BG control(visit 4). They were also warned that they would beadmitted if results continue to be sub optimal afteranother l0 days (visit 5). Those with sub optimalcontrol at visit 5 were admitted and glycemic controloptimized in-hospital. Once optimal BG control wasachieved they were discharged on monthly OPDfollow-ups. Those who did not achieve optimalcontrol but showed an improving trend in BG controlwere also discharged after l0 days of admission andput on monthly follow-ups. Those who did notachieve opt imal contro l and d id not show animproving trend in BG control were re-analyzed withrespect to optimization of medication and thendischarged after l0 days of admission and puton l0day follow-ups.
Jour. Marine Medical Societv, 2007. Vol.9. No.2
The primary end point was to assess if such anapproach led to an increase in 7a ofpatients achievingoptimal BG control. Secondary end points were toassess 7o ofpatients achieving treatment targets forassociated comorbid conditions namely weight (Idealbody weight x. lOVo), Blood Pressure (< 130/80 mmHg) and LDL cholesterol (<100 mgTo) after usingthis approach.
RESULTS
Five hundred diabetics were enrolled into thestudy (visit l). Of these 47 (9.4Vo) had optimalBGcontrol while 4 53 (90.6Vo) had sub optimal BG control.These 453 patients were fbllowed up with monthlyreview and assessed at end of 90 days (visit 2). 52(ll.57o) had optimal BG control while 401 (88.sEo)had sub optimal BG control. These 401 patients wereassessed after another l0 days (visit 3). O7 (1.77o)patients did not turn up as advised, lO (2.57o) hadoptimal while 384 (95.87o) had suboptimalBGcontrol.
TABLE IStudy design
t 1 7
VISIT 1r BASEIINE GIYCEI,IIC COI{'IROIOPTI}|AIT FPG < 13O f,€% &
PPPG < r80 mg%
These 384 patients were assessed after another l0days (visit 4). 13 (3.47o) patients did not turn up asadvised, | 4 (3.6Vo) h ad optimal wh i le 3 57 (93 7o) hadsub optimal BG control. These 357 patients werebriefed about the possibility of admission if theydid not achieve the target BG values in another l0days. These 357 patients were assessed after l0 days(visit 5). 13 (3.6Vo) patients did not turn up as advised,48 (13.47o) had optimal while 296 (82.9Vo) had suboptimal BG control. These 296 patiens were advisedadmission. 24 (8.17o) patients did not get admitted
TABLE 2Basel ine character is t ics
Parameter
as advised, 185 (62.5Vo) had optimal while 87 (29.49o)had sub optimal BG control. Those with optimalcontrol were discharged on monthly follow-ups.After another 3 months of follow-ups it was foundthat most patients (300/309,97Vo) who had achievedoptimal control maintained it. Most patients withsub optimal control at discharge who were on l0day follow ups also showed an improving BG controland at end of 3 months 42187 (48.3Vo) had achievedan optimal control.
DISCUSSION
Our study revealed that frequent targeted OPDfo l l ow-ups fa i l i ng wh i ch a sho r t pe r i od o fhospitalization of patients with sub optimal BGcontrol resulted in a greater percentage of patientsachieving glycemic targets in a health care systemwhere medicines are provided free of cost by thegovernment. This was also associated with a greaterpercentage of patients achieving other therapeutictargets like Ideal Body Weight, Blood Pressure andLDL Cholesterol. Treatment to target is associatedwith full benefits of therapy while sub optimalcontrol is associated with perpetuation of diseaseand increased propensity to develop complicationsboth of which result in increasing disease burdenand cost oftherapy t2-6,81.
TABLE 5Results (secondary end points: Other parmeters)
Optimal contro l (7o)
Parameter
Total
Age
Male:Female
Type 2 DM
DM > 5 years
Ischaemic heart disease
Primary hypertension
Overweight (> l07o IBW)
LDL > 100 mgTo
500 patients
36-82 years
55Vo:45Vo
500 (1007o)
397 ('79.47o)
371t500 ( '74.ZVo)
419/500 (83 .87o)
224t500 (44.87o)
389/500 (77.8c/o)
TABLE 3
Results (Primary end point : Glycemic control)
Total subjects (Baseline)
Basel ine: Opt imal contro l
Baseline: Sub optimal control
Drop outs
Completed
Complet ion: Opt imal contro l
5 0 0
47t500 (09.044o)
453/500 (90.6Vo)
57 /500 ( l | .4Vo)
4431500 (88.6Vo\
356t443 (80.37o)
13091396='181ol
Weight ( lBW t l0olo)
Blood pressure
LDL cholesterol
Basel ine
( n=5 00 )
End of study
(n=443 )
224 (44.8Va)
217 (43.47o)
| | | (22 .27o)
(19. lVo)
(81 . 60 /o )
@8 .1q ( ' )
3 5 0
323
1 9 3
TABLE 4
Results (Per visi t : Glycemic control)
Glycemic
Control
Visit I Visit 2 Visit 3 Visit 5 Pos t
admission
Total Subjects
Op t ima l
Sub Optimal
Drop Out
500 453
47 (09 .47o) 52 (11 .57o)
453 (90.60/o) 401 (88.570)
40 l
l0 (2 .5Vo)
384 (95 .87o)'7 ( l .11o)
3 8 4
14 (3 .67o )
35' / (93o/o)
1 3 ( 3 . 4 0 h \
357 296
48 (13 .4o /o ) 185 (62 .5ok )
296 (82.9o/o) 8'7 (29.47o)
t 3 ( 3 . 6 V o ) 2 4 ( 8 . 1 % \
1 1 8 Jour Marine Medical Societv, 2007, Vol.9, No. 2
Our study shows that frequent targeted OPDfollow-ups of Diabetic patients and a short courseof hospitalization if required signifi cantly increasedthe percentage of patients achieving glycemic andassociated targets. At the end of our study 80.37o ofpatients had achieved glycemic control as comparedto only 9.4Vo at the beginning of the study. Most(1851396,46.7 7o) patients achieved target BG controlduring hospitalization. There was a progressiveimprovement in percentage of patients achievingoptimal BG control during the l0 day OPD visits(visit 3,4 and 5), maximum benefit being observed inthe third lO-day slab when 13.47o of follow uppatients achieved optimal BG control in l0 days.This reflected a gradual improvement in the glycemicprofi les over the previous 110 days of targetedfollow-up. It also pointed towards reluctance ingetting admitted if the control was detected to besub optimal. This compared favorably with I1.57o ofpatients who achieved optimal BG control after initial90 days of monthly-targeted follow-up. Most (977o)of patients who achieved glycemic targets sustainedit after 3-4 months of OPD follow up.
Factors responsible for improvement in glycemiccontrol were analyzed under the following heads(Table 6) . There was an over lap between theinvolved factors in several cases [9]. Most patientswho had dietary indiscretion also had a sedentarylifestyle. There was no significant differencebetween proportions of patients achieving glycemictargets wi th regards to therapy wi th Oralhypog l ycemic agen ts o r I nsu l i n . Howeve roptimization of therapy in most cases requiredaddition of Insulin as combination therapy. At theend of srudy 376/443 (84.87o) patients were on insulinas compared to 316/500 (63.27o) at the beginning ofthe study. Only 04 patients with insulin dropped out
TABLE 6Factors responsible for improved glycemic contro l(of those who completed the study)
Parameter Eo CASes
probably due to the high cost of therapy.
In our study a short duration of hospitalizationhad a marked effect on the glycemic control ofpatients. Hospitalization is free in our set-up, theirbeing no additional costs to the patient. Frequenttargeted OPD follow-ups were also beneficial. Thoseachieving target glycemic control sustained it forthe duration of follow-up of this study. The need forfree medication, which works out costly for mostpensioners, was an important factor in motivatingpatients to adhere to Physician's instructions. Mosto f ou r d iabe t i cs had assoc ia ted co -morb idconditions and hence were receiving a large numberof medic ines. which a lso increased the cost oftherapy. Reluctance for frequent follow-ups as somepatients had to travel long distances to reach thehospital and reluctance for admission in view ofdomestic commitments also contributed to greatercompliance with instructions. Patient's acceptanceofdietary indiscretion and sedentary lifestyle alongwith significant improvement in glycemic controlwith targeted follow-ups reflects that few patientspractice l ifestyle modification especially whenmedicines are provided free.
We recommend that in all Government set-upsand private set-ups where cost of therapy is borneby the Gove rnmen t /o rgan i za t i on / i nsu ranceimplementing such frequent targeted follow-ups andshortperiod of hospitalization will markedly improvepercentage of patients achieving glycemic and othertherapeutic targets. This wil l improve the overallheal th of pat ient , reduce the development ofcomplications and markedly reduce the cost oftherapy saving valuable money for the government/organization.
Drawbacks ofour study included inconvenienceto the patient who had to frequently travel longdistances d isrupt ing thei r domest ic schedules.Monetary circumstances (cost of bus ticket, dailywage earners) forced some patients to drop out whileit was a tough task in motivating elderly patients tocomply with instructions and medication especiallythe ones who had lost the wil l to l ive. Moreover atthe end ofour study 22Vo (87 1396) patients had sti l lnot achieved opt imal BG contro l . Those whoachieved optimal BG control were followed upsubsequently fbr a period of only 3-4 months for
Dietary indiscret ion
Sedentary lifestyle
Sub optimal therapy
None of above
5'l 7o'73Vo
| 4Vo
lOVo
Jour. Marine Medical Society,2007, Vol.9, No.2 i l9
this study. Alonger follow up would have been moreappropriate to assess the percentage ofpatients whosustained their therapeutic targets. We used FBGand PPBG as glycemic targets as they were readilyavailable in our hospital. HbAlc would have been asuperior target for study but could not be used inview of the costs.
CONCLUSION
Treatment forType2 DM is costly, lifelong, andeffective only if the therapeutic targets are met. Suboptimal glycemic control perpetuates diseaseprogression and development of complications.Treatment of complications is costlier causing aheavier expenditure from government funds. In anArmed Forces set up where medicines are providedfree to the patients frequent targeted OPD follow upfailing which a short period of hospitalizationmarkedly improve the percentage of patientsachieving and sustaining optimal glycemic controland associated therapeutic targets. Optimal glycemiccontrol is associated with full benefits of therapyand reduced propensity to develop complicationsboth of which result in reducing disease burden andcost oftherapy. Such an approach can also be appliedto other government /pr ivate set-ups wheremedic ines are prov ided by the government /organization.
REFERENCES
l. Wild S, Roglic C, Green A, Sicree R, King H. Globalprevalence of diabetes: Estimates for the year 2000and projections for the year 2030. Diabetes Care2OO4'. 27 : 1047-53.
2. U.K. Prospective Diabetes Study (UKPDS) Group:
lntensive blood-glucose control with sulfonylureas orinsulin compared with conventional treatment andrisk of complications in patients with type 2 diabetes(UKPDS 33). Lancet 1998; 352 : 837-53.
Stratton lM, Adler AI, Neil HA, et al. Association ofglycaemia with macrovascular and microvascularcomplications of type 2 diabetes (UKPDS 35):Prospective observational study. BMJ 2O0O;321 :405-12.
The Diabetes Control and Complications TrialResearch Group. The effect of intensive treatment ofdiabetes on the development and progression of long-term complications in insul in-dependent diabetesmellitus. N Engl J Med 1993;329 : 977-86.
Herman WH, Dasbach DJ, Songer TJ, Thompson DE,Crofford OB. Assessing the impact of intensive insulintherapy on the health cile system. Diabetes Rev 1994',2 : 384-88.
Wagner EH, Sandu N, Newton KM, McCullock DK,Ramsey SD, Grothaus LC. Effects of improvedglycemic control on health care costs and utilization.JAMA 2O0t: 285 : 1 82-89.
American Diabetes Association: Standards of medicalcare in diabetes (Position Statement). Diabetes Care2O05t 28 (Suppl. l) : 54-536.
Adler Al, Stratton IM, Neil HA, et al. Association ofsys to l i c b lood pressure w i th macrovascu la r andmicrovascular complications of typC 2 diabetes(UKPDS 36): prospective, observational study. BMJ2000:321 : 412-9.
Shah JH, Murata GH, Duckworth WC, Hoffman RM,Wendel CS. Factors affecting compliance in 'Ilpe 2diabetic patients: Experience from the diabetesoutcomes in veterans study (DOVES). Int J DinabDev Ctr ies 2003:23 :75-82.
Jour Marine Medical Society,2N7, Vol.9, No.2
4 .
5 .
9 .
t20
BODY MASS INDEX AND OBESITY : TAILOR MAKING CU]:OFFFOR OUR POPULATION
Lt Col SP Singh-, Surg Lt Cdr Gaurav Sikri*, Lt Col MK Garg*
ABSTRACT
Background : Obesity/overweight is a recognized risk factor for a host of Cardiovascular, Metabolic and otherdiseases/disorders. The disease risk which fatness carries is commonly measured by the Quetelets Index (BodyMass Index - BMI), a surrogate measure of fatness. The current BMI cut-offs utilized by us have been definedin studies on Caucasian populat ions. However, d i f ferences in body structure and composi t ion in d i f ferentethnic, socioeconomic, cul tural and regional groups cause the corr :espondence between BMI and body fatcontent to yary between populat ions. We conducted th is p i lot s tudy in the Indian Navy to def ine our own BMIcut-offs for overweight and obesity using body fat content derived from Skin Fold Thickness as the Standard.
Material and Methods : The study was conducted on i2l volunteers from a naval Hospitals' staff in the age rangeof 18 yrs. to 47 yrs. The mean age, height , weight , BMI, body fat in the study group was 26.73 Yrs (+ 5.59931,168.56 cnt { t 6.1034), 65.92 Kg ( t 10.2746\,23.17 Kg/m square ( t 3.0265) and l9.9 lVo (a 4.831) respect ively.
Results : I'he prevalence of overweighVobesity was 20.66Vo bv BMI and 47,llVo by body fat content. ROC curveanall'sis defined a BMI of 23.85 kg/m! as thc cut off for ovcru'eight with a sensitivity of 70.2Vo (957c C.l 56.6-8f .6)and speci f ic i ty 87,SVo (95Vo CI 76.8-94.4) and a BI ' I I of 24. .18 kg/mr wi th sensi t iv i ty 909c (95Vc. CI 68.3-98.5) audspeci f ic i ty 8 l .2Va (959o CI 72.2-88.3) for obesi ty.
Conclusion : The results of our study suggest lower BMI cut offs for overweight and obesity in Indian populationthan those recommended by WHO and are in concordance wi th s imi lar studies in Asian Indian populat ions inIndia and abroad.
Key Words : Body Mass Index, Body fat content , Skin fo ld th ickness
INTRODUCTION
fibesity is recognized as an important risk factor\-,/for diseases such as CAD, DM Type-Il, CHF,Stroke and Sleep Apnoea among others. The risk ofthese diseases increases as a continuous functionof the percent fat content in the body. However forrisk stratification it is desirable to have cut-off val-ues of body fat content based upon its observedassociation with disease.
The measurement of body fat is too complex,cumbersome and costly to be of practical clinicalapplication. Hence surrogate measures such as the
Quetelet index (Body mass index - measured asWeight in kg/tleight in metres2), which are easilyused clinically, are applied in daily practice. Thismeasure however suffers from two major drawbacks(i) it does not differentiate between body fat an fat
free compartments so that a high BMI may indicateeither increased fat or fat free mass and (ii) bodycomposition being affected by ethnicity, grorvthpatterns, socio-economic, cultural and behavioralpatterns. The same BMI in people of differentethnicities and background may reflect different fatcontents.
The criteria that we use today are suggested byWHO guidelines [] (Table l). These huve beendeveloped by western researchers based on studiesin Caucasian populations and in no way are designedto be appl icable to a l l populat ions. Importantdifferences exist in the form of higher/lower bodyfat content for a given BMI in South-east Asians,Polynesians, Micronesians and Asian Indians togive a few examples [,2]. Further theAsian Indiangroup consists of people of many ethnic i t ies,
'Graded Specialist (Physiology); *Graded Specialist (Physiology), Department of Physiology: *Classified Specialist (Medicine
and Endocr inology), INM. c/o INHS Asvin i , Near RC Church, Colaba, Mumbai 400 005.
Jour. Marine Medical Society, 2007, Vol.9, No.2 12l
different cultural, socioeconomic and demographicprofiles who might have different fat content for agiven BMI value.
Hence this study, the first of its kind in the Indiannavy was conducted to attempt to define BMI cut-off levels corresponding to body fat content of 207oand 25Vo, which are the levels above whichindiv iduals are labeled overweisht and obeserespectively Table I [3].
MATERIALANDMETHODS
The study was conducted on 12l healthy malevolunteers from a Naval Hospital's staff in medicalcategory SlAl. An init ial cl inical history was takenand examination done to rule out any systemicd i sease . A l l sub jec t s we re hea l t hy . Themeasurements to be made were described andinformed consent was taken.
Anthrop o nte tric m e as ur e me nts
Body weight was measured to the nearest 100gm using a. balance beam weighing scalq. Theindividuals were stripped to the waist, all trouserpockets were emptied and shoes removed beforebody weight measurement. Height was measuredusing a metal stadiometer to the nearest 0.5 cm. BMIwas calculated as the weight in kilograms dividedby the square of the height in meters.
Body fat content was measured by the skin-foldthickness method. Skin-fold thickness was measuredat four sites, namely biceps, triceps, sub-scapularand supra-il ic skin-folds. A Harpenden skin-foldcaliper with accuracy of 0.2 mm was used for thepurpose. For the t r iceps and b iceps sk in- fo ldthickness, a horizontal line was circumferentiallydrawn at the midpoint between the acromion and
TABLE IWho classi f icat ion of overweight /obese
BMI Kg/m'z
the olecranon and the skin-fold thicknesses weremeasured over the biceps and triceps at this pointwith the arm pendant. The sub-scapular skin-foldwas measured 1.5 to 2 cm below the lower angle ofthe scapula at 45'to the horizontal. The supra-il iacskin-fold was measured at a point halfway betweenthe iliac crest and the lowermost margin of the ribsin the mid-axil lary l ine at 45'to the horizontal. Allmeasurements were made on the right side of thebody in all the subjects. The measurements wasrepeated thrice at each site and the arithmetic meanof the three readings considered as the skin-foldthickness at the site. The sum of all four skin-foldthickness' was used to calculate body fat contentby the formula of Durnin and Womersley which hasbeen validated for use in Asian Indians [4,5].
Statistical Analysis
Data was recorded on a proforma and managedin a Microsoft Excel worksheet. Means and standarddeviations of all anthropometric variables werecalculated. Receiver Operating Characteristic (ROC)curves were drawn to determine appropriate cut-offpoints of the BMI for defining a)overweight and b)obese. Body fat percentage measures as derivedfrom skin-fold thickness were considered thestandard. Analys is was done using MedCalc-version-9.1.0.1 statistical software. A p value of <0.05 was considered significant.
RESULTS
The present study included I 2 I male sailors. Theirdetails are as given in Table 2.
The age distribution of the subjects is shown inF i g . l .
The distribution ofoverweight and obese by age
TABLE 2Age, height, weight, BMI and body fat 7o in
subj ects
Range Mean (+ SD)Underweight
Normal weight
O verweight /Pre-obese
Class I obesity
Class II obesity
Class lll (morbid) obesity
< 1 8 . 5
1 8 . 5 - 2 4 . 9
25-29.9
3 0 - 3 4 . 9
3 5 - 3 9 . 9
> 4 0
Age
He igh t
Weight
B M I
Body Fat Vo
l 8-49 yrs
1 5 4 - 1 8 9 c m
41 .2 -112 kg
l7 .7 -35.95 kglmz
10.87 -33 .4Vo
2 6 . 7 3 ( s . 5 0 9 8 )
1 6 8 . 5 6 ( 6 . 1 0 3 4 )
6s.92 (tO.2746)
23.1'r (3.0265)
1 9 . 9 1 ( 4 . 8 3 1 )
, 1 4 Jour Marine Medical Sociery,2007, Vol.9, No.2
4049<20
30-3924o/o
20-29680/
Fig. 1: Age distrihlt ion of the subjects.
groups by BMI and Body Fat percent are as givenin Table 3. The correlation between the two measuresis a lso g iven.
Of the 25 overweight/obese by BMI one hadGrade II, and three Grade-I obesity, while therema in ing 2 l we re ove rwe igh t . By body fa tpercentage on the other hand thirty-five people wereoverweight and twenty- two obese. Of thoseoverweight by BMI three (l21o) had fat content inthe normal range.
The sensitivity and specificity of BMI as adiagnostic tool for all overweight subjects in ourstudy was calculated to be 38.6Vo and 95.317o
TABLE 3Distr ibut ion into obese/overweight of study subjects
TABLE 4
ROC data for our study at suggested cut-off points; which
I Cannot
d at this. Use ofmplantshe facio:r/lower;an alsorfts I I 3]may be:ries [91th much)genesls: case ofing soft
:s thet i cge. Therased onssue or
Overweight Obese
Body fat Vo
Suggested BMI curoff
Sensi t iv i ty
Speci f ic i ty
PPV
NPV
P value
2 5
> 24.38
9 0
8 1 . 2
4 8 . 6
9'7 .6
.000 r
respectively with a positive predictive value of 887oand a negative predictive value of 63.54Vo. For aBMI curoff of 30 kg/m2 for obesity the sensitivitywas only 18.87o and specificity was 1007o with aPPV of 1007o and NPV of84.627o.
ROC curves were drawn to delineate the cut-offfor overweight and obesity. The data for both thecurves at suggested cut-off points are given inTable 4.
DISCUSSION
In this study we have attempted to define BMIcut-off points for defining overweight and obeseusing Skin Fold Thickness as the standard test.
We calculated a BMI cut-off of 23.85 Kg/mr foroverweight/obese. Using this value the number ofoverweight/obese increased to 49 whereas withconventional values of 25 kglm'z the number wasalmost half, only 25. Further although the number offalse positives increased from 3 to 8 the number offalse negatives decreased from 35 to 18, just overhalf.
t n
> 2 3 . 8 5'70.2
8 7 . 5
26.4
97.9
.0001
: fibers
residualre abovefined byct ional /ans l iketics etc.
Age
groups
N u m b e r
overwei ght/obese
BMI Body fat 7a
Percentage of group
overweightobese
BMI Body fat Vo
Correlat ion
< 2 0
20-29
30- 39
40-49
12.2
4 1 . 3 8
7 5
3 6 . 5 9
82.76
7 5
3645
6'144
6 8 1 9
7 1 4 8
l 0t 25
3 01 A
J
Total ) /25 20.66 7201
l .9 , No.2 Jour Marine Medical Society, 2007, Vol.9, No.2 r23
Similar data suggesting lower BMI curoffs forAsian Indians has been found in studies in Indiaand abroad. In a study by Dtdeja et a/ at the AIIMS,New Delhi in 123 North Indians. 86 males and 37females, the authors have proposed a BMI cut-offvalue of 2 L5 Kg/m2 corresponding to 25Eo body fatfor males and 19 kg/m2 for females [6]. Their datagenerated a sensitivity of 86.7, a specificity of 89.3and positive and negative predictive values of 8 1.3and92.6 respectively at a BMI cut-off of 21.5 kg/m2.The sensitivity, specificity and NPV in our study ata BMI cut-off for obesity (BF-257o) of 24.38k91m2are similar, however the positive predictive value issignificantly lower at 48.6Vo. This could however bedue to the fact that their subjects had a prevalenceof obesity of 34.\Vo, while in our subjects thecorresponding figure was 18.187o. Also their studywas restricted to a north Indian population whileours had a heterogeneous mix of people from allparts of the country. Since the Indian and henceNaval population is a multi-ethnic population it isvery l ikely that significant differences in bodycomposi t ion would be present in people f romdifferent parts of the country.
In another study on l4l men by Bhat et al inPune approximately equal number of men from ruralbackground, urban slums and middle class citydwellers were studied for body fat content [7]. Theyreported that using a Body Fat percentage of 257oas cut-off 29.5Vo rural. 467o urban slum and 757ourban middle class subjects were obese. On the otherhand using WHO recommended BMI cut-off's 97orural,22%o slum dwellers and2TVo urban middle classwereoverweightwhile only 4Vo of theslum dwellersand none of the rural or urban middle class wereobese. They therefore suggested the use of bodyfat measures and not BMI for risk stratification inIndian men.
Piers e/ n/ in a s tudy publ ished in Austra l iacontend that BMI is good for population studiesbut i l l-applied in individuals, a fact that is borne outby our study [8]. The need for population specificBMI cut-off is an imperative and even then, thismeasure must be applied to the individual with greatcaution.
There is no doubt that increased body fat contentis a harbinger of disease and when excessive, a
124
disease itself. However we have to bear in mind thatamongst obesity related disorders obesity is butone r isk factor and as the Amer ican HeartAssociation in its 2005 update of the 1997 Statementon Obesity and Heart Disease says "...even if weightloss is minimal, obese individuals with a good levelofcardio-respiratory fitness show a reduced risk forcardiovascular mortality as compared with lean,poorly fit subjects" [9].
Drawbacks of the study
In this study we have used body fat contentderived from skin-fold thickness as the standard forfat content measurement. This was done because ofthe ease of application of this method and itsrelatively low cost. However the method itself hasan error of 3 to 99n in calculation of body fat I l0].
This study was an init ial attempt to verify thevalidity of BMI cut-ofi as suggested by the WHO,for body fat content measurement in our clientpopulation. Hence we have settled for a small samplesize.
We have not analyzed the data by region of thecountry that the subjects belong to. This was againnot possible because of the small sample size.
In this paper we have made no attempt to conelatebody fat content or BMI with other risk factors ordisease prevalence or incidence i.e. the associationbetween body fat and d isease has not beenaddressed.
Recommendations
L This is a pilot study. Based on our findings it issuggested that further large-scale studies beconducted to define BMI cut-off points forove rwe igh t and obese spec i f i c t o ou rpopulation.
2. A BMI cut-off of 225 kg/mz for overweight and30 kg/mr for obesity has a very low sensitivityin our population. Hence due caution must beexercised when using these criteria in decidingon obesity. Wherever possible calculation ofbody fat from skin-fold thickness must be thecriterion used.
REFERENCES
l. The problem of overweight and obesity Part L Pg. 9.
Joun Marine Medical Society, 2007, Vol.9, No.2
mind thatity is butrn HeartStatementrif weight
;ood level:d risk forvith lean,
t contentrndard for,ecause ofd and itsitself hasfat I l0].
verify theheWHO,lur clientall sample
ion of thewas againsize.
r conelatefactors or;sociationnot been
dings it istudies beroints for' to our
,eight andensitivityr must bedeciding.lation ofrst be the
r L P g . 9 .
t l .9,No.2
4 .
5 .
6 .
Geneva 2000: WHO Technical Report Series E94.
Yap MD, Schmidt G, van Stavem WA, Deurcnberg P.The paradox of low body mass index and high body fatpercentage among Chinese, Malays and Indian inSingapore. International Journal of Obesity 2000;24: l 0 l l - 1 7 .
Singh RB, Niaz MA, Beegom R, Wander GS, ThakurAS, Rissam HS. Body Fat Percent by Bioelectricallmpedance Analysis and Risk of Coronary ArteryDisease Among Urban Men with Low Rates of Obesity:The Indian Paradox. Journal of the American Collegeof Nutrition 1999; 18 (3) : 268-13.
Durnin JVGA, Womersley J. Body fat assessed fromtotal body density and its estimation from skinfoldthickness: measurements on 481 men and women agedfrom 16 to 72 years. Br J Nutr 1974; 32 : 77-97.
Kuriyan R, Petracchi C, Ferro-Luzzi A, Shetty PS,Kurpad AV. Validation of expedient methods formeasuring body composition in Indian a,druJts. IndianJ Med Res 1998; 107 :37-45.
Dudeja Y Misra A, Pandey RM, Devina C, Kumar GVikram NK. BMI does nt accurately predict overweight
Jour. Marirc Medical Society, 2007, VoL9, No. 2
in Asian Indians in northern India. Britislr Journal ofNutr i t ion 2001; 86 : 105-12.
Bhat DS, Yajnik CS, Sayyad MG Raut KN, Lubree HG,Rege SS, et al. Body fat measurement in Indian men:comparison of three methods based on a two-compartment model. /zt J Obes (Lond) 2005:'29 (7): 842-8.
Piers LS, Soares MJ, Frandsen SL, O'Dea K. Indirectestimates of body composition are useful for groupsbut unreliable in individuals. Int J Obes Relat MetabDisord 2OO0:24 (9) : 1145-52.
Poir ier R Giles TD, Bray GA, et al. Obesity andCardiovascular Disdse : Pathophysiology, Evaluation,and Effect of Weight Loss. An Update of the 1997American Heart Association Scientific Statement onObesity and Heart Disease from the Obesity Comrnitteeof the Council on Nutrition, Physical Activity, andMetabolism. Circulat ion (1524-4539\; 2005 Dec(Cited 2006; Feb l9): ll3 (22p). Available from http://circ.ahajournals.org.
Lukaski HC. Methods for the assessment of HumanBody Composition: Traditional and New. Am J ClinNutr 1987: 46 : 537-56.
125
7 .
8 .
9 .
t 0 .
RUGGED, PORTABLE BIOMEDICAL DATA ACQUISITION ANDTRANSMISSION SYSTEM _ TELEMEDICINE SYSTEM FOR ARMEDFORCES
SR Sumathi-, DT Shakunthala-, PS Pandian-, Uma U Maheshwari', Mohan K Velu*,AnuradhaSrinivas', KPSafeer-rMadhabi Sarkar-rDeepa prabhu', SG Gruruprasad', pM Sagat'.,Jyotsna Shahpurkar', Dr BS Sundersheshu', Dr VC padki'--
ABSTRACT
The medical f ield around the globe has made several advances catering to various health benefi ts. Thesefacilities are still limited in availability to the privileged section of the population at super specialty hospitatsin urban areas. This paper discusses the functionality and featur'es offered by the ruggbd, poitabl" BiomedicalData Acquisit ion and Transmission System (Tele Medicine system) that has been Oeveloped by DEBEL forintended use for f ield appl icat ions in the Armed Forces. I t presents a detai led descript ion of t le hardware,software and communication facilities of the system. The system consists of rugged hardware to acquire vitalparameters of a patient and a MIL grade laptop which houses the software to operate the system, store acquireddata and facilitate interfacing communication device for exchange of data. Various communication modalitiesare incorporated to cat€r to the need for field and hospital environments. The system has successfully undergonetesting for military environmental conditions and EMI/EMC for electronic ground equipment for army. It hasalso undergone patient safety tests as per IEC standards. The paper also dwells on various issues connected wirhoperability of the system in the intended scenario and utility in general in the context of Armed Forces, Thesystem has spin off benefits of its usage for civilian sector in rural areas,
Key words : Biomedical Data Acquisition, Ttansmission system, Rugged hardware
I., -t
" , t r' ..ll'a
INTRODUCTION
Th" need for expert opinion in medical emergenI cies or crisis has opened up opportunities for
development of Telemedicine systems capable ofacquiring diagnostic data, communicating it to amedical expert for opinion. Various systems [1-7]have been developed to cater to different scenariosof usage adopting suitable technologies. The sys-tems are targeted for civilian usage such as in disastermanagement, providing specialist facility to rural hos-pitals, home to practitioner etc.
The very nature of duty of soldiers makes themprone for medical emergencies. The medicalassistance to the troops deployed in forward andfield areas is organized at different levels [8]. Thoughthe medical staff at the field hospital is trained inhandling many medical emergencies, there are manyoccasions where lack ofproper expert advice delaysthe decision regarding course of treatment and
proper emergency care. Hence there is.a dire needfor connecting the field MI rooms to the specialistmilitary hospitals. The specialist at the remote sitecan give expert opinion on handling the emergencyor guide on triage and evacuation. Though suchsystems are available abroad, [9-15] they are notcurrently used in forward/field areas in the IndianArmed Forces scenario.
DEBEL has developed the telemedicine systemwith the main aim of providing a portable and ruggedsystem which can assist an Armed Forces doctorwho is seeking expert opinion during a triageoperation at MI room in forward areas. The systemconsists of rugged hardware to acquire v i ta lparameters of patients such as ECG Blood Pressure,Resp i ra t i on Ra te , Hea r t Ra te , SaO2 , bodytemperature through the Data Acquisition System(DAS) and a MIL grade laptop which houses thesoftware to operate the system, store acquired data
r1
v
v
rt
'Scientist; '.Ex Scientist; "'Director, Defence Bio erigineering and Electro Medical Laboratory
t26 Jour Marine Medical Society,2007, Vol.9, No.2
and facilitate interfacing communication device forexchange of data. The system has facility to capturevideo images e.g. pictures of wound using a highresolution digital camera. The acquired patient videodata clip along with doctor's comments in audio canalso be transmitted. The salient feature of the systemis its ability to communicate data on the S-bandportable SAICOM terminal, which is presently beingused in armed forces for voice communication. Italso supports other communication media such asVSAT. PSTN and ISDN which would find use whenthe system is operated in a different scenario otherthan field. The operating software takes care ofarchival and maintenance ofthe data through usageof robust and secure database.
System Overview
Fig. I shows the block diagram of the system.
The system is designed to operate in a store andforward manner. It facilitates the user to acquire vitalparameters such as 12 lead ECG Blood Pressure,Respirat ion Rate, Heart Rate, SaO2, Bodytemperature through the DAS and store it locallybefore transmitting it to the expert. The user canalso acquire images related to patient through adigital camera and record audio (3 minute) throughheadset. The experts can send in their commentseither through text or audio.
SYSTEM DESCRIPTION
A) Physiological/Biomedical DAS (BIODAS)
BIODAS is a peripheral device capable ofacquiring 12lead ECG Oxygen saturation, Bloodpressure along with respiration and temperature fromthe human body and sends it to a PC. The PC cansubsequently relay the information to the physician,in Real-time, such that during the consultation viavideoconferences the physician ig better equippedto d iagnose and t reat the pai ient . The uni t isdesigned for rugged terrain applicration with duereliability and accuracy, at the same time maintainingthe standard qualifying it for military environment.BIODAS works on the state-of-art Li-ION batteryand can provide continuous monitoring in excess of4 hours on full change. The unit is lightweight andcompact and can easi ly be a par t of groundequipment and can play a vital role in saving human
Jour Marine Medical Society, 2N7, Vol.9, No.2
daF-iq-
Fig. I :Blockdiagram.
Fig.2 : BIODAS blockdiagram.
lives during emergencies.
The block diagram of BIODAS is shown in Fig. 2.
BIODAS consists of the following main modules:
1) ECQ Respiration, Temperature Module
2) Pulse Oximeter Module
3) Non Invasive Blood Pressure Module
4 CPUModule
t Power Supply Module
O Battery Section
7) Softkey touchpad, LED indicators
The system is built around a modular concept.The system incorporates multiple intelligent PCBs.
127
These modules are capable of acquir ing andprocessing individual patient parameter. Thus wehave modules for ECG respiration and temperature,pulse oximetry and for non-invasive blood pressure.To control the entire system and interact with PCthere is a master controller card. This module isresponsible for ascertaining the smooth functioningof the machine. The patient input is taken by meansof respective transducers. Arrangement is made onthe front panel of the system for proper and secureattachment of the probes. The connection to thePC, i.e. the output from the machine is provided onthe back parrel. Additionally few controls like takinga BP reading and reset are also provided on thefront panel. The system can be powered on fromboth mains as well as battery, if mains are unavailable.
1. ECG, Respiration, Temperature Module (ERTmodule)
This ERT module is responsible to:
o Pick up and buffer ECG, respiration andtemperature signals from patient
o Provide desirable isolation to patient from safetyviewpoint
o Process the ECG signal to remove unwantednoise frequencies to get the desired frequencyresponse of 0.05 Hz - l25Hz
o Provide amplification so as to adhere to ECGstandards
o Calculate ttre heart rate from the ECG waveform.
o Extract the respiration signal
o Compute the temperature value
o Synchronize the data and send to main CPU
2. Pulse Oximeter module
BIODAS works on the principle of differentialabsorption of Red (600-750 nm) and Infrared (850-1000 nm) lights by Hemoglobin. The Transmissionmethod for measurement is employed wherein theoximetry probe acts as both receiver and thetransmitter i.e. there is an emitter on one side and areceiver on the other with the measuring site inbetween. This module has the necessary algorithmsfor computat ion of oxygen saturat ion in lowperfusion and motion conditions.
128
3. Non Invasive Blood Pressure module
BIODAS uses automatic non-invasive bloodpressure measurement, which essentially apply theprinciple of oscillometry. This method allows bloodpressure measurement in pre-operative, operativeand post-operative patients with muted Korotkoffsounds. A single cuff is applied to the patients arm,and the system inflates it to a level assumed to begreater than systolic pressure. The cuff is deflatedg radua l l y . A senso r t hen measu res the t i nyoscillations in the presence of the cuff caused bythe pulse.
4. Main CPU module
This card is the heart of BIODAS unit. This cardperforms followi ng functions:
o Communicating with the host
o Communicat ing wi th the pat ient in ter facemodules
o Synchronizing the patient data received fromthe modules
o Monitor Battery status and send feedback
o Receive inputs from keyboard
o Generate user interface signals for display ofI,ED'S
5. Power Supply module
This card is responsible for supplying the powerto various components of BIODAS. Input to powersupply operates from external l2V 2Amp externalSMPS. Power consumption of BIODAS is less than12W. Suitable low power regulators are incorporatedto control the power to the various modules therebygiving control on the power usage. This is importantfrom the battery usage point, whereby limited powercan be wisely utilized, based on the need and undercontrol of host. Protection is provided with respecttoEFT2.5KVESD,4KV
6. Battery module
BIODAS is being designed to work for 4 hourson fully charged medical grade battery. Approximatecurrent requirement would be 300 mA, with 500 mAsurges during NIBP operation. Hence 200mAHrbattery is used.
Jour Marine Medical Society, 2007, VoL9, No.2
7. Softkey touchpad, LED indicators module
a) Keys for the following functions are designed:
1) NIBP StarUStop
2) Reset the unit enabling the BIODAS to startin default mode.
b) Mechanical rocker switch is provided forswitching on the unit and LED indicators areprovided for:
l) Power indication
2) Battery charging/full charge indication
3) Data Transmission indicator
Ruggedness and EMI/EMC (Military) qualificationof BIODAS
This BIODAS is developed to be used in militarytelemedicine applications. Any electronic systemsbeing used in military environment have to passthrough the MIL grade environmental testing andEMVEMC testing. Our system has successfullyundergone testing for military environmentalconditions as per JSS 55555 [6] and EMIIEMC [7]for electronic ground equipment for army. It has alsoundergone Patient safety tests as per IEC 60601-l[8]. The BIODAS unit has successfully passed thefollowing environmental tests.
l) Vibration
2) Low and High operat ional and storagetemperature
3) Bump
4) Drop
t High altitude and
0 Relative humidity
The BIODAS has also successfully passed theEMI/EMC conducted/radiated emiss ion andimmunity tests.
B) BIODAS Software
The software is developed to operate in storeand forward fashion for transmission of data with aprovision for immediate transmission in times ofemergency. The store and forward mode of operatronwas considered for some benefits like
* When the transmission is delayed temporarilydue to snag in the communication media, patientneed not be held up for data acquisition process
Jour. Marine Medical Society, 2007, Vol.9, No.2
* In situations of second opinion, presence ofexpert doctor at the instant of transmission isnot mandatory since the data can be extractedfrom the data base and reviewed
* In situation when bandwidth limitations arise,like in the case of S-band SATCOM terminal.there may be a small delay in transmitting thedata but no data losses are foreseen
The Application software developed has twomajor modules CSLP (computer software laptop) andCSPC (computer software personal computer) whichrun on Windows XP and interface with MicrosoftSQL Server for data archival. CSLP and CSPC willtake care of operating the system at the consultingdoctor's end i.e. Telemedicine Consultation Center(TCC)[9] and specia l is t /expert doctor 's endTe lemed ic ine Spec ia l i s t s Cen te r (TSC) [ 9 ]respectively. The software is developed based onIF,EE 12207 [20] standards.
Using the software at TCC, the user can acquirethe following data, store the data into the database,establish communication with TSC and transmit thedata.
* Patient demography and case history.:. Biomedicaldata/Vitalparameters
o 12 lead ECG [0 seconds], Blood Pressure.Body temperature, SaO2 [Oxygen saturation],Respiration Rate, Heart Rate, Mean arterialpressure
* Three minute audio
* Image [with annotations] acquired throughcamera
Following are some of the additional features pro-vided apart from the above tasks..:. View summary of all the cases stored in the data
base
o Case wise ordata wise l isting of all existingdata
o Listing of cases pending for
o Transmission of data
o Receiving experts report
c Experts reports to be viewed
* Select a particular case using above op:ions to
o Extract data of the selected case for viewrns
t29
the data
O Send the data to expert doctor
O View arrived report
o Update case details or finish acquisition ofdata for current visit
o Update deta i ls and acquire data forsubsequent visits of old cases
TSC module executing at the expert doctor end takescare of following tasks
* Receive case data sent from TCC.l Store the data in the database.! View received data and generate report (text or
audio)
* Transmit report to TCC
Following are some of the additional features pro-vided apart from the above tasks..:. Mew summary of all the cases stored in the data
base
O Case wise or date wise l isting of all existingdata
o Listing of cases pending for
o Transmission of report
o Generation ofexpert report
t Select a particular case using above options to
O Extract data of the selected case for viewinqthe data
O Generateexpertreport
O Transmit expert report
Both TCC and TSC software provide features foruser authentication, configuring the details ofcommunicat ion device avai lable, se lect ion ofcommunicat ion media opt ion, f ix ing date forteleconferencing, display of 12 lead ECG with 5,10,20mm/mV sensitivity and 25,50 chart speed, annotationof an image data by both the doctors, contextsensitive help.
RESULTS AND DISCUSSION
The system was tested in the laboratory with afew subjects. Medical doctors were present in theteam to evaluate the performance of the system. Theacquired medical data was transmitted via C BandVSAT. ISDN. PSTN facilities installed at DEBEL. The
130
Transmission through S Band was tested at DEAL,Dehradun. The screen shots of the transmitted andreceived patient data is shown in Fig. 3 and Fig. 4respectively. The system was working satisfactorily,the transmission and reception were successful.Trials are being planned to evaluate the system inremote locat ions. Any modi f icat ions/changessuggested by doctor can be easily incorporated intothe system software.
CONCLUSION
A portable biomedical data acquisit ion andtransmission system has been developed with theprimary intention of its uti l i ty in armed forcesscenario. The hardware for acquiring the biomedicaldata (vital parameters) has been designed andcertified for its intended use in harsh environmentalconditions. The unit is lightweight and compact andcan easily be a part of ground equipment and canplay a v i ta l ro le in saving human l ives dur ingemergencies.
The features offered by the software enables itto be used by both the f ie ld areas wherecommunication modality such as S-band SATCOMterminal/VSAT terminals can be uti l ized and in
- 4 . . - - -
- , - d ib
. ffirriil
Fis. 3 : Screen shot of transmitted biomedical data.
(.:m
Fig. 4 : Screen shot of received biomedical data.
Jour. Marine Medical Society,2a07, Vol.9, No.2
r-'5r
hospitals where PSTN/ISDN facilities are available.Though it operates in store and forward fashion,transmission of data can be immediate in times ofemergency. At times when second opinion is therequirement, especially when the system is used ina hospital scenario, then data can be accumulatedfor multiple patients and sent for expert opinion.
The complete system is evaluated in the lab. Thesystem has additional features compared to any othercurrently available telemedicine systems in India.The system once proved in f ie ld t r ia ls holdstremendous potential for Telemedicine applicationsin Defence as well as civil sector.
RJTERENCES
t. Negoslav Daja, et aJ. Telemedicine in cardiology-ECG
Transmission by mobile phone - Annals of the academy
of studenica 2001.
2. Majumdar AK, et al. TELEMEDIK: A Telemedicine
system for providing quality health care in rural areas,
Souvenir of seminar on Telemedicine - A Vision turned
Mission, l9 March 2004.
3 . Sa t yamur thy LS . Te lemed i c i ne - A hea l i ng t ouch
through space for speciality health care delivery to
remote and rural population. Sourvenir of seminar on
Telemedicine - A Vision turned Mission, l9 March
2004.
4. Chatwal Vikram. Apol lo hospi ta ls group and
Telemedicine. Souvenir of seminar on Telemedicine -
A Vision tumed Mission, 19 March 2004.
5. Mode l, GATS report, India : Telemedicine Initiatives
in India
6. Mishra SK. Telemedicine at SGPGI. Lucknow - current
programmes and future perspectives.' l
. CCS 7500A Portable Telemedic ine System,
www.globalcoms.com
8. Rai KM. et al. Treatment of causalities in a forward
Jour. Marine Medical Society, 2007, Vol. 9, No.2
I t .
hospi ta l of the Indian Army: Nine year exper ience
MJAFI2004I 60 : l
Answering the call, Medical lmaging July 2004; l9 (7)
: 34-3 ' l .
Susan R Mcgrath, et a/. AMEMIS : A vision for remote
tr iage and emergency management informat ion
integrat ion.
Chaoxina Sima, el al. Yital signs services for secure
Telemedic ine appl icat ions, Concurrent engineer ing
research centre, West Virginia University.
Kyiaco E, et a/. Multipurpose Healthcare Telemedicine
Syslemswith Mobi le gommunicat ion Link Support ,
Biomedical engineering online 2003: 2.
Ari T Adler. A cost effective portable telemedicine Kit
for use in developing countr ies, MS Thesis,
Massachusetts Institute of Technology, May 2000.
Telemedic ine reference archi tecture project -
Enabling the next generation of telemedicine Devices,
Sandia Research Laboratory
David Hai ley, st aJ. Assessments of Telemedic ine
applications - an update, Alberta heritage foundation
for medical research.
16. JSS 55555 : Jo in t serv ices spec i f i ca t ions fo renvironmental tests for electr ical and electronicequlpment.
ML 46lE : Military standard for EMC requirements
and measurement methodology.
IEC 60601-l Patient safety standards for biomedical
e lectronic equipment.
Technical working group on Telemedic ine
standardizat ion, Recommended guidel ines and
standards for practice of Telemedicine in India. May
2003.
IEEE/EIA 12207.2 - Standard for lnformationtechnology software life cycle processes - life cycledatz 199-1.
13] ,
1 0 .
l 2
l 3
t 4
1 5 .
1 7 .
l 8
1 9 .
20.
AIRCREW FATIGUE : THE HIDDEN DANGER
.Surg CdrRC Verma'
ABSTRACT
This art icle describes the ftrain causes of Aircrew Fatigue, contr ibutory factors and the preventive measuresneeded to avoid Aircrew Fatigue.
Key Words : Aircrew Fatigue, Causes and prevention
INTRODUCTION
flying does not depend on a single measurableI (and degradable) skill. It requires an integrationof many skills such as working memory, vigilance,spatial ability, psychomotor functioning, etc. whichcan be degraded by fatigue.
Flight duty time limitations (FDTL) have beenpromulgated in the civil aviation and the NavalAviation has the Squadron SOPs to guard againstaircrew fatigue. Unfortunately, the guidelines arevery simplistic as they only take into account thetotal number of sorties that can be undertaken byday and night per day/week/month. No attempt hasbeen made to include the variables such as time ofstarting duty/flying, actual time on duty, number oftake off/landings, etc. which are known to influencethe development of aircrew fatigue. Thus, theSquadron SOPs on aircrew fatigue need tr-l bereviewed. The introduction of Night Vision Gogglesand capability of Air to Air Refuelling (AAR) willfurther compound the problems of aircrew fatigue inthe near future as the former can play havoc withthe circadian rhythm and the latter will increase thetime on task.
Tlpes of Fatigue
o Physical Fatigue includes muscle soreness orfeeling of tiredness due to sleep deprivation,i l lness or poor nutrit ion
o Mental fatigue is typically associated with tasksdemanding in tense concentrat ion, rapid orcomplex information processing and other highleve l cogn i t i ve sk i l l s such as I ns t rumen tMeteorological Conditions (IMC) at unfamiliar
airport, air combat manoeuvring or it may arisefrom prolonged activity as in sustained alertnessduring maritime search patrols or long haul low
.level f l ightso Emotional Fatigue or Burn Out results from
repe t i t i ve o r mono tonous ac t i v i t y i n t hebackground of low motivation
o It is important to remember that stressors seldomoccur in isolation and when together, they act inconcert and the effect is synergistic
Incidents and Accidents
Fatigue in aviation safety has been a topic ofinvestigation since the earliest days of aviationpsychology (Barlette, 1953). Epidemiological studiesof accidents demonstrate a strong influence ofworking hours, time of day and disruption of sleep.However. t i l l date there is a lack of evidenceconcerning the core dimension of safety and a lackof conceptual c lar i ty about the nature andmechanisms of fatigue. The Canadian Blizzard Report(Pilot Fatigue Study Group, 1988) could not musterenough evidence concerning aviation Fatigue. UKBader report on FDTL (1973) was essentially anappeal to commonsense rather than hard evidenceto formulate the FDTL.
A i r c rew fa t i gue f i gu res p rom inen t l y i nconfidential reporting systems for aviation incidents.The category of fatigue, flight time limitations andcommercial pressures feature in reporting to the UK,Confidential Human Factors, Incident ReportingProgramme (CHIRP) in the recent years. In the USA,theAviation Safety Reporting System (ASRS) datareveals 207o reported incidents ofcrew fatigue.
'Classified Specialist, NAS Kunjali.
132 Jour Marine Medical Society, 2007, Vol.9, No. 2
Pattern of Accident Rates
o Time at Work : The time spent on the task is notthe only factor which gives rise to fatigue andenhances the risk of accident. Perhaps total timespent at work is more important than time spenton a particular task
o Time ofWork (Night): Borowsky and Wall(1983)reported that Naval Aviation Mishaps show amarked diurnal distribution with a much lowerrate of accident for flights originating between0900 -1800 hrs than at other times
e Disruption of Sleep : Blom andPokorny (1985)reported that the earlier the morning start time,the higher the ratio of accident. Perhaps there isa disruption of sleep with early start times
o Second Circadian Peak : There may be a secondearly afternoon circadian peak of accident or otherfatigue effects, particularly for those who havebeen at work for longer
r Cumulative Fatigue and Extended Rest :Cumulative fatigue is produced by a pattern ofprolonged work and inadequate rest and sleep orby successive night shifts
o Task and Fatigue : Rather than the task itselfbeing instrumental in causing fatigue, perhaps itis the total pattern of daily activity and the way itis distributed over the 24 hour cycle which makesa clearer contribution to accident rate
r lrregular Schedules and Time Zone Changeso Organisational and Professional factors : Both
the professional ethos of the individual and theclimate of organisation governing his work mayplay a cruc ia l ro le because i t is here thatarrangements interface with and negotiate therealities of everyday life
Sources of Aircrew Fatigue
The sources can be in the pre-flight or in-flightperiods.
Pre-Flight Sources
a) Physical causes such as exposure to heat, noiseand high relative humidity.
b) Physiological sources include inadequate sleepand rest, malnutrition, poor physical fitness andundue physical exertion.
c) Pathological carises include a sub-clinical orclinical i l lness.
d) Pharmacological sources include prescribed or
Jour Marine Medical Society,20Q7, Vol.9, No.2
self medication.
e) Psychosocial stress may be introduced by thenight parties, interpersonal relationships and anunhealthy squadron environment.
f; Psychological sources include worries, maritaldiscord, accommodation hassles, commutingproblems, motivation, f inancial matters andalcohol or drug abuse.
In-Flight Sources
a) Physical sources such as heat, noise, vibrationand posture.
b) Physiological causes include disruption of sleep-wake cyc le , du ra t i on on task , hypox ia ,hypoglycaemia and high G forces.
. c) Pathological causes may be due to an in-flighti l lness.
d ) Psychosoc ia l sou rces i nc lude unhea l t hyinterpersonal relationship, poor Crew ResourceManagement, antagonism and rank structure.
f ) Psychological s t ress may occur due topreoccupat ion wi th l i fe s t ressors, in- f l ightemergencies, combat and motivation.
Contributory Factors
There is more to fatigue than the identification ofstates oftiredness, drowsiness and falling asleep inthe period immediately prior to an accident. Fatigueis paradigmatically associated'not only with timeand with time spent at a particular activity, but alsowith time spent awake in various activities, time onduty, time for sleep, rest and recuperation and theway these are patterned in relation to endogenousphysiological rhythms, notjust over one cycle, butover an extended period. Thus, cumulative fatiguecan develop with a pattern of prolonged work andinadequate sleep and rest.
Accidents normal ly have many interact ingcauses and it may be rare for a state ofbehaviouralor subjective impairment, sufficient to be calledfatigue, to be identified as a contributory factor.Fatigue may have a more subtle and pervasive effectdetectable only by looking at the distribution ofaccident in relation to time and duration of exposure,because fa t i gue i s i nex t r i cab l y l i nked w i thimpairments associated with duration and time.
Effects of Aircrew Fatigue
The effects of fatisue include an increased
1 3 3
reaction time (timing errors, less smooth control),decreased attention (vigilance tasks, sequentialtasks, scanning) and diminished memory (inaccuraterecall, forgetting peripheral tasks, reverting to oldhabits). Thus, fatigue can have critical effects onsafety margins in aviation.
The mood may be withdrawn which affects mindand emotions, there is decreased conversation, easydistraction and the aircrew may be irritable with"Don't Care Attitude" and skip SOPs.
Subtle Mental Incapacitation (SMI) can occur.The aircrew may acknowledge warning signal ofimminent danger, but take no conective action. Theexact cause of SMI is not known, but contributoryfactors include fatigue, alcohol, life style changesor intolerable events of life. SMI can range fromdrowsiness at one extreme and acute awareness.even panic at the other extreme and there is abreakdowri or diminution of a recently acquired skill.
Operational Significance
Fatigue affects the mind and emotions of the body.Aircrew fatigue can compromise pilot efficiency, pilotwell being, mission effectiveness, passenger safetyand flight safety.
Major Concerns of Fatigue
An increase in mishap potential due to Loss ofSituational Awareness and increased susceptibilityto Spatial Disorientation.
An impaired ability in handling an emergency orunexpected combat situation i.e., loss of advantage.
RELIABLE MEASURES FORDIAGNOSIS OFNATIGI.JE
Due to the nature of fatigue and it's multitude ofvariables, there is no single test/procedure whichcan reliably measure the degree of a pilot's fatigueor to ascertain at what point fatigue causes in-flightperformance decrement, i.e., fatigue is not amenableto accurate measurements.
Several chemical and physiological abnormalitieshave been reported in literature such as changes inurine-blood catecholamines, urinary l7-keto steroidsand l7-hydroxycorticosteroids, sodium-potassiumratios and aberrations in blood chemistry. Schreuder(1966) quoted a decreased BP, increased pulse rateand decreased pulse pressure induced by fatigue/stress. Some studies have reported an increase in
134
ESR and polymorphonuclear leukocytes and adecrease in WBC and Eosinophil count.
PREVENTION OFAIRCREW FATIGIIE
lndoctrination of aircrew :
a) On the causes of fa t igue and i t 's potent ia loperational consequences.
b) Reporting i l lness, avoiding i l l icit drug abuse andself medication and ensuring good nutrition andgood health.
c) To self-introspect the various sources which canlead to fatigue in the pre-flight period.
d) To devise personal countermeasure strategies inorder to minimise the development of fatigue.
Review of existing Squadron SOPs
A review of Squadron SOPs to promulgate morerealistic "fatigue limits" than the simple yardarm thattalks about the total number of sorties by day/nightper day/week/month and also to include the aircrewflying with NVGs andAAR capable aircraft.
Indoctrination of the Senior Supervisors
In order to ensure that reasonable f ly ingschedules are planned, in order to obviate taskingof jun ior a i rcrew wi th unreal is t ic miss ions byfollowing the philosophy that "There is no peacetime mission which cannot be carried out later".
Use of Drugs under supervision
Pharmacological help to aircrew involved inextensive flying activities for a short duration suchas carrier operations and fleet exercises. A project tointroduce this concept in the Naval Aviation may beundertaken under the aegis of NAMC, Goa.
CONCLUSION
The many operational stresses of flight inducefatigue to some degree - perhaps fatigue is aninherent stress of aviation duties. Although fatiguemay be neatly defined as acute, chronic or cumulativeand correlated to some extent with biochemicalaberrat ions, we are not yet able to determineobjectively at what point a pilot is fatigued enoughto cause in-flight performance decrement. Due tothe insidious nature of aircrew fatigue which cancompromise the man, machine and mission, the riskof aircrew fatigue must be reduced by preventrvemeasures.
Jour Marine Medical Society, 2007, Vol. 9, No.2
Points considered before Aero medical disposal
l . ENT specia l is t took into considerat ion subject ivecomplaints of the officer to award reslriction inemployability. Officer was thus considered fit forall duties.including sea service in cat S2Al, in viewof being a naval officer which entailed in additionto a pilot, going to sea in various staff appointmentsincluding WKO, XO, CO, etc.
2. The indian Naval Aviation Publications II (Article
0125) states: Ii an officer is considered unsafe forafloat flying, he shall not be grounded but be utilizedfor flying from shore.
3. Towards investigation ofAircrew flying from shore,an executive report highlighting factors such asmotivation, air sickness, cockpit performance andapprehension of f ly ing, etc. is mandatory, forreview at IAM, Bangalore.
4. Further, KA-25 Helicopter being a single pilot andsingle Navigator Aircraft, placing the pilot in "A3"category would be equivalent of p lacing him in"A4" category and thus would prevent theexamination/executive report on ashore flying byis flying Supervisor.
The med i ca l boa rd conduc ted a t INHS Ka l yan i
recommended LMC S2Al/A2Cl (T-12) wef 26 Oct. 06.
However, the recommendat ions were not approved by
Higher Authorities who also advised to place the Air crew in
LMC S3A l /A4G l (T -12 ) v i de IHQ, MOD(Navy ) l eue r
No.MHl30l dated l4 Dec. 06. Accordingly, the medical
board reassembled and recommended post facto LMC S3Al/
A4C1 (T-24\ wef 26 Oct. 06 in consonance wi th the
directive from higher medical authority.
The Aircrew has been flying from ashore in the interim
period pending finalization by'medical Board. He has flown
35:30 hours both by day/night since then. The Aircrew has
been examined pre and post f ly ing dur ing th is per iod at
random intervals by aviat ion medic ine specia l is t and has
been found fit and free from fatigue. The executive report
on shore based flying pertaining to the aircrew by his flying
Supervisor (QFI and Commanding Officer of the Squadron)
compliments the Aircrew and reveals no abnormalitl like
Fa t i gue , A i r s i c kness , app rehens ion t o f l y o r l ack o f
mo t i va t i on , e t c .
He was next referred to IAM Bangalore for
Recategor isat ion Medical Board when i t was due, wi th
Execu t i ve r epo r t on Asho re f l y i ng i n Ap r . 07 . As t he
complete physical and psychological evaluation at IAM did
not reveal any abnormality, the Aircrew was upgraded to
full flying category (AlGl). However, flying from ship was
left to the disposal of the Administrative authorities. Here,Para 6.10.16 i lAP 4303 (3rd edi t ion) l is re levant which
stages, "ln cases of service officers, any case of airsickness
will be evaluation at IAM and those who are not found to
136
have any organic cause will be awaided full flying category
and recommended adm in i s t r a t i ve d i sposa l " . The
recommendat ions of the board carr ied out at IAM have
been duly apprbved by HQ ENC in May' 07.
Again, in the month of August the air crew was directed
to emba rk a des t roye r f o r M IN ITACEX '07 wh i ch he
complied. He was unable to under take sorties when directed,
he undertook the launches, but he had to cut down the
sort ies wi thout complet ing the mission because of h is
disability. Ship's mediial officer put him down for the rest
of the sailing duration in view of his symptoms. Feedback
obtained f rom f l ight commander is not .compl imentary.
Observers flying with him felt unsafe and ship's captain was
also apprised by them. Presently, the aircrew is active in
ashore flying, pending administrative disposal for his afloat
f ly ing
DISCUSSION
"Mal de Mer" is a rather pleasant and unassumingFrench term for the debil itating effect motionsickness may have on our body. Likely, it is notusually life threatening although many sufferers wishit were if only to bring relief to the extreme discomfortthey feel! Everybody, 9O7o of all people will havesuffered from it at some point in their lives [5]. In hisbook The Human Body, Isaac Asimov related theanecdote about a seasick passenger whom a stewardcheerfully assured that nobody ever died fromseasickness. The passenger muttered, "Please--it'sonly the hope of dying that's keeping me alive" [6].
Sea sickness happens when the body, inner ear,and eyes all send different signals to the brain,resulting in confusion and queasiness. It is a problemgenerally attributed to disturbance in the balancesystem of the inner ear (vestibular) system. Oursensory perception gets out of sync as these nervefibers attempt to compensate for the unfamiliarmotion of the ship moving through water [7].
The movement of a ship on a fluid sea createsstress in the portions of the brain responsible forbalance. Perhaps that stress causes the brain to startmalfunctioning as the land based environment itunderstands is suddenly not behaving as it should.The visual stimulus is misleading as it reports thingslike cabin walls, and furniture, in such a way that thebrain interprets these things as stable when theyare not. Our brain is being told by the vision systemthat the wor ld is s table, whi le the inner ear isscreaming that it 's not.
Jour. Marine Medical Society, 2007, Vol. 9, No. 2
The senses, no doubt, had often much to do withsea sickness; but, certainly, not always; person havebeen awakened from sleep by the occurrence ofsickness. Fear was not always present: the mostcourageous persons frequently suffering fromsickness. It was well known that Nelson, who 'never
knew fear', was incapable, for many days, of leavinghis berth from sickness, and Sir John Franklin wasnever able to take charge of his ship until he hadpassed the Bay of Biscay. It is a special psychophysiological condition and susceptibility appearsto run in families, with childhood histories includingintolerance for riding in the back of the family car ora bus [8] .
Sleepiness can often be the first sign and somepeople who think they don't get seasick actually dcwithout realizing it. People who love to take a napthe moment they get out onto the water are probablyfeeling the effects of mild motion sickness. Aftersleepiness comes the nausea but it is often mild andmay not be much of a problem. However, for manyunfortunate souls, as in the case of the abovementioned pilot, the symptoms escalated to extremenausea, vomiting, dizziness, headache, pallor andcold perspiration warranting detention in sickbayduTingMINITACEX'07.
Taking into consideration, aircrew's disability, weneed to seek answers to the following questions.
a) Why the aircrew is sea sick but not air sick?
b) Is there any psychological reason for this?
Sea sickness Vis-a-Vis Air Sickness
t . Aircrew's adaptation to sailing is temporary andfor short duration, i.e. only during embarkation,where as his adaptation to flying is permanent
There is a continuous motion stimulus for longduration during sail ing, where as in flyingmostly, it is during aerobatics only and for avery short duration. The frequency, magnitude,direction and duration of motion stimuli aredifferent in sailing vis-a-vis flying
Enclosed spaces and smell of engine fumes ofship may also be a contributing factor
The psychological characteristics of individualalso play a major role.
Indian Naval Air Publication (INAP), article 0125:
Jour. Marine Medical Sociery,2007, Vol.9, No.2
partly described below laid down guidelines foradministrative disposal of this aircrew.
INAP Article 0125 Aircrew who are accident - proneor below standard :-
1. Pilots who are considered to be accident-pronefor deck landing only need not be groundedand may be allowed to fly shore-based aircraftat the discretion of the Administrative Authority
2. When no psychological or medical reasons canbe found for a pilot, he should not be groundedand may be allowed to fly shore-based aircraftas per the succeeding paragraphs.
a) The Capta in is to send a s ignal to theAdministrative Authority repeated to NavalHeadquarters and Flag Of f icer NavalAviation requesting a check flight or flyingtest by an appropriate unit.
b) When the appropriate flying test has beenarranged, the Captain is to forward a reporton the flying ability of the pilot, togetherwith the reason for applying for the test, tothe President AIRCATS sending a copy tothe Administrative Authority and Flag OfficerNaval Aviation.
c ) On comp le t i on o f t he f l y i ng t es t , t hePresident AIRCATS is to make a reportdirectly to the Naval Headquarters (copy toAdministrative Authority and Flag OfficerNaval Aviation) who will decide whether thepilot is to :-
i) Return to his unit for full f l1,ing duties
ii) Be attached temporarily (for a specifiedlength of time or number of flying hours) toanother unit where he may obtain flyingpractice before returning to his original unit
iii) Be converted to another type of aircraft
iv) Be removed from the flying cadre
3 . Any ac t i on t aken by t he Admin i s t ra t i veAu tho r i t y i s t o be repo r ted to Nava lHeadquarters
Presently the position of aircrew is status quo,pending administrative disposal, what should be thecorrect d isposal? Is i t grounding or opt imalutilization of trained aircrew?
4.
137
His disposal is best described in US Navy flightsurgeon's manual, 3rd edition Section III "Aviationdisposition" related to problematic case, which isstated below:
What is to be done with a problem patient - theaviator whose medical problems 1) do not renderhirn unfit for further service, 2) suggest a possibleimpact on aero medical safery, but 3) does not fitneatly into a laid down water tight policy thatwould alter his flying status?
Whether the evaluation is as causal as ac'onversation with a pilot in the passageway, or as
formal as a Special Board, every evaluationperformed seeks answer to questions : I ) Is th"eindividual safe to perform his aviation duties, and2) Is the individual likely to remain so in the future?General agreement could be expected on the NotPhysically Qualifted (NPq status of the young
flight cadet very early in the pilot training syllabus.Disagreement might be expected, however aboutthe fate of a Lieutenant Commander with I4 yearsof service and several fleet tenures who suffers thesame problem. He dffirs from the cadet in severalways
I. The Navy's investment is considerably greaterin training the aircrew
2. His experience is obviously greater
3. The aviation experience of the LieutenantCommander might allow him to compensate
for the defect.
4. Thefuture demands the Navy will make on theindividual's services are dffirent
CONCLUSION
Occasional ly , a case ar ises that , due to i tscomplexity or its uniqueness, warrants referral to aspecial medical board. Unfortunately, many of theconditions that result in convenins df medical or
administrative boards lead to termination of flight
.status. Board members should always keep in mindthat their action will have a significant impact on thefutule of the aircrew. Revocation of flight statusmeans a decrease in pay, a significant change in hislife plans and career pattern, and frequently, adamaging blow to his self esteem. Board membersshould a lso be mindfu l of the fact that theorganization will be losing a trained aircrew bygrounding him, even if, aircrew has got certainemployability restrictions. Therefore, the action ofthe board must not only be correct, it must beacceptable and understandable to the servicecommunity. In other words, Should we not optimallyutilize a trained aircrew instead of grounding him?
REFERENCES
l. Benson AJ. Motion sickness. ln: Ernsting J Nicholson
AN. Rainford DJ. eds. Aviation Medicine. 3rd edition.
Oxford: But terworth-Heinman; 1999 : 455-61.
2. Mi l ls KL, Gr i f f in MJ. Ef fect of seat ing, v is ion and
direction of horizontal oscillation on motion sickness.
Aviat Spare Environ Med 2OOO: ?l : 996-1002.
3. Park RE, Hu S. Gender d i f ferences in the mot ion
sickness history and suscept ib i l i ty to optokinet ic
rotation-induced motion sickness. Aviat Space Environ
Med 1999l '70 : 1077-80.
4. Jones DR, Levy RA, Gardener L, Marsh RW, Panerson
JC. Sel f -contro l of psycho physio logic response to
motion stress using biofeedback to treat airsickness.
Aviat Space Environ Med 1985:56 : ll52-7.
5. Sea sickness available at http://seasicness.co.uU
6. Sea sickness. Availabltj at "http://en.wikipedia.org/wiki/
Sea-sickness"
7 . De ha r t L Roy . Spa t i a l o r i en ta t i on i n f l i gh t .
Fundamentals of Aercispace Medic ine: 2nd ed.
Bal t imorel Wi l l iams and Wi lk ins, 1996 : 385-96.
8 . Rayman B Russe l l , Has t i ngs D John . Psych ia t r y .
Clinical aviation medicine. 3rd edition: Castle Connolly
Graduate Medical: 2000 : 305-06.
Jour Marine Medical Society, 2007, VoL9, No.2l ,38
I
I.MED
lr"r
ef i ts . TheseI ty hospi ta ls: BiomedicalDEBEL for
e hardware,rcquire v i ta lore acquiredn modal i t iesy undergonearmy. I t hasnnected withForces, The
.a dire needre specialistremote srte
)emergencyhough suchhey are notn the Indian
cine system) and rugged)rces doctorng a triageThe systemqu i re v i t a lod Pressure,rO2 , bodyiion Systemhouses the
:quired data
,'*1
COMPREHENSIVE NEURO CT IMAGING IN ACUTE STROKE:WHAT'S NEW?
PradiptaCHande.
ABSTRACT
Comprehensive Neuroimaging in stroke is a fast and easy method for assessing cerebral blood flow. The articlediscusses the neuro CT imaging modali t ies avai lable and their usefulness in acute stroke.
Key Words : Neuro G Imaging, Stroke.
)' a
INTRODUCTION
A pproximately TOVo of all acute stroke are the.6result of cerebral ischaemia with reducedperfusion in the area of blood supply of one of thecerebral arteries.
In acute stroke urgent neuroimaging is requiredand plain CT brain is widely available today. Theadvent of possible therapeutic strategies for acutestroke has increased the need for a simple, quick,reliable and effective method ofassessing cerebralblood flow in patients with acute stroke []. DynamicPerfusion CT studies is a rapidly emerging techniquetbr stroke studies.
METHODSAND MATERIALS
Pat ients of acute st roke wi th hemispher icsymptoms are studied with urgent Plain CT brain.Perfusion CT is done where first passage of nonioniciodinated contrast bolus through cerebral vesselsis acquired with fast scanning on CT.
Cerebral perfusion parameters were calc.ulatedfrom the dynamic curves for the regions of interest.The cerebral blood volume (CBV), mean transit time(MTT), cerebral blood flow (CBF) are the marncontributory parameters that help to study t[edistribution of the blood flow in the brain. Displayusing colour maps of these curves were utilized forvisual analysis.
RESULTS
Perfusion CT done after ursent Plain CT brain as
neuroimaging was performed in patients with acuteischaemic stroke. The most commonly affected agegroup was between 40-50 years.
The calculated CBV, CBF values show theperfusion distribution in the brain gray and whitematter. Post processing and analysis of the short-teri'n changes in the density of the brain tissue froma time-density curve is plotted of the slice beingexamined.
Plain CT : NormalPlain CT : l2l4o
Perfusion CT : The findings of abnormal perfusionwas detected in 29 cases which showed defects ofCBY CBFand/or both.
In 12 of these patients there was early ischaemiawhich is a good indicator of ischaemic 't issue atr i s k ' a n d i s s i g n i f i c a n t . D S A a n d c a t h e t e rthrombolysis was done in the suitable cases to re-establ ish c i rcu lat ion in the pat ients wi th ear lyperfusion defects with CBV/CBF mismatch.
There were regions of irreversible damage in l2cases. However, in 5 patients mixed CBV/CBFparameter alterations were noted in the differentparts of the affected area, studied at the centre andthe periphery of the defect.
Sensitivity in the study =29134 x 100 = 85.37o
DISCUSSION
Acu te ' s t rokc - i s usua l l y d iagnosed byneurological examinuti.in and urgent neuro imaging.Noncontrast plain CT brain is done to exclude
I
a
7. Vol.9. No. 2
'Classified Specialist. Radiology, INHS Sanjeevani.
Jour Marine Medical Soc.iety, 2007, Vol.9, No.2 1 3 9
haemor rhage Dynamic Pe r fus ion CT w i thcontinuous acquisition of data using multi detector.CT scanner is very usefu l as an adjunct toconventional Plain CT in the present day to studythe cerebral perfusion changes.
The slices are selected depending on the vascularterritory, performed after injection of IV nonioniccontrast medium using pressure injector. Contrastinjection rates in our protocol were 5ml/sec whichwas the minimum required for obtaining data foranalysis as was used in standard studies [2].
Time-attenuation curves are plotted for theregion from the slice examined for changes in thedensity of brain tissues. Cerebral blood volume(CBV), mean transit time (MTT), cerebralblood flow(CBF) are calculated using the available software.
Time-to-peak (TTP) values can be compared withconesponding healthy areas to indicate disturbedperfusion. In regions with extensive ischaemia(permanently damaged), a substantial reduction inCBF and in CBV (matched defects). CBF/CBVmismatch is a good indicator of ischaemic 'tissue atrisk' (analogous to perfusion/diffusion mismatch inMRD. Perfusion CT correlated well with final infarctsize as reported in literature [3].
False-negatives noted in Perfusion CT resultswere related mainly to a lack of spatial coverage, ashas been reported for other dynamic Perfusion CTtechniques [4]. In patients with lacunar or other smallstrokes and those with strokes in the posterior fossacareful evaluation is suggested in hyperacutesettings.
Dynamic CT perfusion imaging could help todetermine whether IV thrombolysis, intraarterialca the te r recana l i za t i on , hepa r i n i za t i on ,neuroprotective medication, hypothermia, or earlydecompression craniotomy is indicated [5]. CTangiography can also be completed at the same timewhich helps in recent years become a focal point oftherapeutic interest for the treatment of patients with
140
embolic ischaemic strokes.
Perfusion CT helps in selection of patients withembolic ischaemic strokes to be taken up for earlythrombolysis (local or systemic). Greater chances ofsalvageable ischemic areas were found in patientspresenting within 3-6 hrs (window period) of onsetof symptoms as found in reported studies [6].
CONCLUSION
Comprehensive Neuro CT including PerfusionCT is a fast and easy to perform imaging method forthe early diagnosis of acute stroke and evaluationof cerebral perfusion disturbances.
REFERENCES
l . So rensen AG, Copen WA, Os te rgaa rd L , e t a l .
Hyperacute Stroke: St imul taneous measurement of
relative cerebral blood volume. relative cerebriil blood
f low, and mean t issue t ransi t t ime radio logy. 1999:
210 : 519-2'1 .
2. Wintermark M, Maeder B Thiran JP, Schnyder P,
Meuli R. Quantitative assessment of regional cerebral
blood flows by perfusion CT studies at low injection
rates: a cr i t ical review of the under ly ing theoret ical
models. Eur Radiol 2001: 1 I : 1220-3O.
3. Koenig M, Klotz E, Luka B, Venderink DJ, Spittler JF,
Heuse r L . Pe r f us i on CT o f t he b ra i n : d i agnos t i c
approach for ear ly detect ion of ischemic stroke.
Radioktgy 19961'209 : 85-93.
4. Konig M, Klotz E, Heuser L. Diagnosis of cerebral
infarct ion using perfusion CT: State of the ar t
radiology. 1999:2O9 : 85.93.
5. Ueda T, Sakaki S, Yuh WT, Nochide I, Ohta S. Outcome
in acute stroke wi th successful int ra-ar ter ia l
thrombolysis and predict ive value of in i t ia l s ingle-
pho ton em iss i on -compu ted t omog raphy . J Ce reb
Bktod Flow Metab 1999; 19 : 99-108.
6. Schramm B Schellinger PD, Klotz E. Comparison of
pe r f us i on compu ted t omog raphy and compu ted
tomog raphy ang iog raphy sou rce images w i t h
perfusion-weighted imaging and di f fus ion-weighted
imaging in pat ients wi th acute stroke of less than 6
hours duration. Stroke 2004:35 : 1652.
Jour. Marine Medical Society,2M7, Vol.9, No.2
lI
t
t
0nl ;
ll-
reaction time (timing errors, less smooth control),decreased attention (vigilance tasks, sequentialtasks, scanning) and diminished memory (inaccuraterecall, forgetting peripheral tasks, reverting to oldhabits). Thus, fatigue can have critical effects onsafety margins in aviation.
The mood may be withdrawn which affects mindand emotions, there is decreased conversation, easydistraction and the aircrew may be irritable with"Don't Care Attitude" and skip SOPs.
Subtle Mental Incapacitation (SMI) can occur.The aircrew may acknowledge warning signal ofimminent danger, but take no corrective action. Theexact cause of SMI is not known, but contributoryfactors include fatigue, alcohol, life style changesor intolerable events of life. SMI can range fromdrowsiness at one extreme and acute awareness.even panic at the other extreme and there is abreakdowri or diminution of a recently acquired skill.
Operational Significance
Fatigue affects the mind and emotions of the body.Aircrew fatigue can compromise pilot efficiency, pilotwell being, mission effectiveness, passenger safetyand flight safety.
Major Concerns of Fatigue
An increase in mishap potential due to Loss ofSituational Awareness and increased susceptibilityto Spatial Disorientation.
An impaired ability in handling an emergency orunexpected combat situation i.e., loss of advantage.
RELIABLE MEASURES FOR DIAGNOSIS OFFATIGI.JE
Due to the nature of fatigue and it's multitude ofvariables, there is no single test/procedure whichcan reliably measure the degree of a pilot's fatigueor to ascertain at what point fatigue causes in-flightperformance decrement, i.e., fatigue is not amenableto accurate measurements.
Several chemical and physiological abnormalitieshave been reported in literature such as changes inurine-blood catecholamines, urinary l7-keto steroidsand l7-hydroxycorticosteroids, sodium-potassiumratios and abenations in blood chemistry. Schreuder(1966) quoted a decreased BP, increased pulse rateand decreased pulse pressure induced by fatigue/stress. Some studies have reported an increase in
134
ESR and polymorphonuclear leukocytes and adecrease in WBC and Eosinophil count.
PREVENTION OFAIRCREW FATIGT]E
Indoctrination of aircrew :
a) On the causes of fatigue and it 's potentialoperational consequences.
b) Reporting illness, avoiding illicit drug abuse andself medication and ensuring good nutrition andgood health.
c) To self-introspect the various sources which canlead to fatigue in the pre-flight period.
d) To devise personal countermeasure strategies inorder to minimise the development of fatigue.
Reyiew of existing Squadron SOPs
A review of Squadron SOPs to promulgate morerealistic "fatigue limits" than the simple yardarm thattalks about the total number of sorties by day/nightper day/week/month and also to include the aircrewflying with NVGs andAAR capable aircraft.
Indoctrination of the Senior Supervisors
In order to ensure that reasonable f ly ingschedules are planned, in order to obviate taskingof jun ior a i rcrew wi th unreal is t ic miss ions byfollowing the philosophy that "There is no peacetime mission which cannot be carried out later".
Use of Drugs under supervision
Pharmacological help to aircrew involved inextensive flying activities for a short duration suchas carrier operations and fleet exercises. A project tointroduce this concept in the Naval Aviation may beundertaken under the aeeis of NAMC, Goa.
CONCLUSION
The many operational stresses of flight inducefatigue to some degree - perhaps fatigue is aninherent stress of aviation duties. Although fatiguemay be neatly defined as acute, chronic or cumulativeand correlated to some extent with biochemicalaberrations, we are not yet able to determineobjectively at what point a pilot is fatigued enoughto cause in-flight performance decrement. Due tothe insidious nature of aircrew fatigue which cancompromise the man, machine and mission, the riskof aircrew fatigue must be reduced by preventrvemeasures.
Jour Marine Medical Society, 2007, Vol. 9, No.2