diving safty & decompression meter

gasabeh.com [email protected] 27/دسامبر/12 1

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Diving Safty and Decompression Meter ((Dive Computer, Decompression Computer

Dr.A.EBADI.AEROSPACE & DIVING MEDICINE,ARMY UNIVERSITY OF MEDICAL SCIENCE. 12/27/دسامبر gasabeh.com [email protected]

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INTRODUCTION

gasabeh.com [email protected] 27/دسامبر/12

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-Professional Association of Diving Instructors (PADI)

-National Association of Underwater

(NAUI)Instructors

(BSAC)Aqua Club -British Sub- -Confederation Mondiale des Activites

(CMAS) Subaquatiques

CERTIFICATES


8 2000-2006-Diving Alert Network(DAN) 12/27/دسامبر gasabeh.com [email protected]

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DISCUSSION


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A:Decompression Sickness (DCS) History:

and compressed air workers diversDCS recognized in -since late 1800s

was to ascend slowly guidelinePrevailing -

ft/min5 ft/min to 1.5 Standards ranged from

less frequentlyDCS still occurred but -

nitrogen bubblesDCS associated with -

: Shorter/shallower dives associated with less Haldane-frequent/less severe DCS


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Decompression Theory nitrogen at depth tissues absorbs Body -

absorbs nitrogen at different ratetissue type Each -

releases nitrogen Slow, staged ascent (“decompression”) -and is exhaled Stages determined by time/depth of harmlessly

each dive

nitrogen bubble decompression causes without adequate Ascent -formation

= “Decompression Sickness” manifestationsClinical

)obstructiveDestructive,compressive,(

6 % within 95-after dive minutes to hoursTypically presents -hours


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Type I DCS Musculoskeletal pain (Limb bends)-

manifestation of DCSMost common

, not well localized; no change with Dull painmovement

, elbows, or shoulders most commonly Kneesinvolved

DCS (Skin bends) Cutaneous-

Pruritis and erythema of trunk

Treatment: Recompression-


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Type II DCS

Risk of permanent disability or death-

Pulmonary DCS (“Chokes”)- clog pulmonary arterial gas emboli Venous -

circulation

from deep diverapid ascent Rare; occurs with -

discomfort, cough; worse with deep Substernal- inspiration

and sided heart failure -rightMay lead to - collapsecardiovascular


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)con’tType II DCS (

Neurologic DCS spinal cordPredilection for -

deep divesRecreational divers doing short, -

after ascentminutes to hours over –Syndrome -

-Tingling in trunk

-Progressive numbness and paresthesias

-Ascending motor weakness

-Bowel/bladder incontinence

-Severe cases may present with LOC/paraplegia

-Cerebral manifestations: memory impairment, aphasias, visual disturbances, personality changes


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)con’tType II DCS ( Vestibular DCS (“Staggers”)

, nausea, vomiting, dizzinessSudden onset of - hearing loss and tinnitus -, +/nystagmus

in recreational diversNot common -

barotraumaConfused with middle ear -

Treatment of Type II DCS: with hyperbaric oxygen recompressionRapid -

Supportive care: Fluids


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SCUBA DIVING SAFTY(most common)

Medical

Planning

Equipmental

Environmental

Decompression Meter (Dive Computer)B:

(Self Contained Under-water Breathing Apparatus)


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are used for planning dives to dive tables Traditionally -avoid risk of DCI

of depth and timesafety limits Dive tables contain -

-There are many standard dive tables, Original UK, US Navy etc.

many (an algorithm Dive tables can be generated by -variations possible)

run these algorithms(Different Dive computers -Algorithm*)

Dive Tables


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Dive Tables


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Decompression Meter (Dive Computer)

Wrist Dive Computer Console Dive Computer 12/27/دسامبر gasabeh.com [email protected]

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Manufacturers -Citizen -Liquivision -Seiko -Suunto -Uemis -VR Technology -Underwater Technology Center


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• Sensors send data to the Analog to Digital (A/D) Converter.

• A/D Converter changes analog data to digital signals.

• The Micro Processor calculates the data and presents it to the diver via the LCD Display.



gasabeh.com [email protected] 24

Depth-Time Profile

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

00'20"

01'40"

03'00"

04'20"

05'40"

07'00"

08'20"

09'40"

11'00"

12'20"

13'40"

15'00"

16'20"

17'40"

19'00"

20'20"

21'40"

23'00"

24'20"

25'40"

27'00"

28'20"

29'40"

31'00"

32'20"

33'40"

35'00"

36'20"

37'40"

39'00"

40'20"

41'40"

43'00"

44'20"

45'40"

47'00"

Time

Dep

th

Bottom Time

Bottom Zone

Surface

A

A

MaximumDepth

0.85% MaximumDepth

min 12.0of bottom timeRisky dive with some minor problems. Because your exceeds no-stop limit by 4.0min this dive is risky. But you performed the ascent

was poor as indicated by ‘saw bottom zonewell. Your buoyancy control in the time profile.-’ on the depthAtooth’ patterns marked ‘

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of gas uptake and release, such as the Mechanical models -1s)1960-through restricted orifices.(SOSmovement of gas

Suuntoof the established decompression tables( Electronic models -2

diving unilevel-USN meter.)

using the decompression theories on which Electronic models -3level diving-multi-)Nx100 different tables.(VEO



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COMPUTERS vs. TABLES

*UNI LEVEL DIVING 12/27/دسامبر gasabeh.com [email protected]

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COMPUTERS vs. TABLES

MULTI LEVEL DIVING 12/27/دسامبر gasabeh.com [email protected]

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dives* Unsafe in dive profiles are known patternsThe following

to cause DCI

(Detect)ascentRapid -

Sawtooth-

dive profile etc. Reverse-


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Rapid Ascent -A pattern in the dive profile caused by the diver

to the surfacerising rapidly

causing critical factor Rapid ascent is the most -bubbles in body tissues

of causing DCIhigher chance Therefore has -

detect rapid Most dive computer software -ascents and sound alarms


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Sawtooth -A pattern in the dive profile caused by the diver

in quick successiondown and up going

-This may not happen very frequently, but when it happens it may cause the tissues to absorb excess gas bubbles

cause DCITherefore may -

does not detect themDive computer software - gasabeh.com [email protected] 27/دسامبر/12

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Reverse Profile -This is a pattern observed at the level of a

.whole dive profile

-Ideally a diver is required to initially reach the and then all the planned maximum depth

subsequent dive should be performed at a depth shallower than the maximum

-A reverse profile is a dive profile where the reverse of the idealdiver performs the


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*CharactristicsPersonal

1- Age 2- Sex

3-BMI-(Fatty Tissue Percent)

4-Health State (DM-HLP-Nutrition-Metabolism)

5-Body Position & Activity


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CONCLUSIONS


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از کننده استفاده غواصان صعود زمان کاهش به توجه با

DECOMPRESSION COMPUTERS احتمال افزایش وبنابراین

Hyperbaric Chamber به ونیاز DCS بالینی عالیم بروز

: شود می توصیه

فشار برداشت جداول همراه وبه کمکی صورت به غواصان -1

را موضوع این نمایندو استفاده ها دستگاه این از استاندارد

.دهند قرار نظر مد متر 30 از بیش های غوص در بخصوص

منظورکنترل به بایست می ها دستگاه ازاین استفاده درصورت -2

احتمالی برداشت بیماری عالیم وبهبود Hyperbaric فشار Chamber حاضرباشد غوص درمحل.


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گرینویچ ساعت براساس زمان کردن استاندارد همانند -4

وبا المللی بین قبول قابل مبدا یک اساس بر استاندارد غوص،

مطرح، غواصان فشاربرای برداشت بیماری ریسک حداقل

قرارگرفته جهانی تایید مورد مرتبط های سازمان وازسوی براساس DECOMPRESSION COMPUTERS مختلف وانواع

.گردد تنظیم آن

ایمنی ارتقائ درجهت زمینه دراین بیشتر تحقیقات انجام لزوم -5 DECOMPRESSION COMPUTERS با غواصی


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SAFETY GUIDELINES the Dive Computer(instruction/ Authorized understand how to use Fully -1

Oceanic Dealer )

presented in the Operating function varies from the information Any display or -2Manual (Authorized Oceanic Dealer )

condition (do not dive until the battery is replaced)Low battery -3

(Dive Computer must be verified, or set)dive NitroxEach -4

(if available) in normal zones throughout your dives.bar graphs The -5

deepest dive firstAlways make your -6

and experiencethe level of your training Always limit your dive to -7

between each diveadequate surface interval Allow an -8 12/27/دسامبر gasabeh.com [email protected]

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SAFETY GUIDELINES

M)(greatly 39 (FT 130 deeper than Decompression diving, or diving -9increase your risk of decompression sickness

10-Decompression diving is inherently hazardous and greatly increases , even when performed according your risk of decompression sickness

to the Dive Computer’s calculations.

of no guarantee Using a Dive Computer, just as dive tables, is -11avoiding decompression sickness


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Refrences 1- Petar J. Denoble, MD., D.Sc Alessandro Marroni, MD. D.S Richard D. Vann, Ph.D.Common Factors in Diving Fatalities Fatality Workshop, Durham April 8-10, 2010

2-www. DivingCaribbeanNicheMarkets.

3-www. Wikipedia, the free encyclopedia- Dive computer

4- Carl Edmonds M.B., B.S. (Sydney), Christopher Lowry M.B., B.S., John Pennefather B.SC. Robyn Walker M.B., B.S., Dip. D.H.M. Diving and Subaquatic Medicine 4th Edition 2002

5-Wilmshurst peter.Technological advances in scuba diving do not always increase safety.Bjsm.bmj.com.2011

. gasabeh.com [email protected] 27/دسامبر/12

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