question 1 (12 marks) - litfl
TRANSCRIPT
UNIVERSITYHOSPITAL,GEELONG
FELLOWSHIPWRITTENEXAMINATIONWEEK24–TRIALSHORTANSWERQUESTIONSSuggestedanswersPLEASELETTOMKNOWOFANYERRORS/OTHEROPTIONSFORANSWERSPleasedonotsimplychangethisdocument-itisnotthemastercopy!
Question1(12marks)A3yearoldboypresentstoyouremergencydepartmentaftertaking10Lomotiltabletsapproximately1hourago.NB:(Diphenoxylate-atropine-wellknowntradenamesmaybeusedintheexamratherthangeneric)
a. What istheroleofdecontaminationforthispatient? Includetwo(2)points inyouranswer. (2marks)• Charcoalisindicated• Ifpatientcooperativeandalert• Notrequiredforfavourableoutcome• Mayreducenaloxonerequirement• MayreduceLOS
b. Listfour(4)examinationfeaturesthatyouwouldexpectatthisstage.(4marks)
• Opiod:o DecreasedGCSo Respiratorydepressiono Miosis
• Anticholinergic:o Delirium/agitationo Tachycardiao Urinaryretentiono (dryskin)
Allofthesefeaturesarepresent.Youassessthepatienttohaveseveretoxicity.
c. Statefive(5)keystepsinthemanagementofthispatient.(5marks)• Naloxonebolus• Naloxoneinfusion• SupportA/Basrequired-notlikelytorequireintubation• AdmittoHDUfacility-continuousnoninvasivemonitoring• Feedbacktofamilyaboutsafestorageofmedications
d. Statethetimeframethatyouwouldexpectthepatienttorequirehospitalisation,ifthepatient
experiencesnofurthercomplicationsofhisingestion.(1mark)• >48hrs
“List”=1-3words“State”=shortstatement/phrase/clause
Question2(18marks)YouaretheconsultantinchargeofaregionalbasehospitalED.A17year-oldgirlisbroughtinbyherparentswitha6-monthhistoryofweightloss.
a. Statethefour(4)keycomponentstothediagnosisofAnorexiaNervosa.(4marks)NB:DSM-5isundergoingareviewandthisanswershouldbeupdatedinnearfuture.Belowistheanswerbasedonrecommendedtexts:
• Selfinducedwtloss/restrictionofenergyintake• Bodywt>15%belowexpectedorBMI<17.5• Pathological/intensefearofwtgain/becomingfat• Bodyimagedistortion• (amenorrhoea≥3menstrualcycles-thisobviouslycannotbeappliedtomales,pre/postmenstrualfemales)• (associatedendocrinedysfunction)
b. Listseven(7)examinationfindingsthatyouwouldseekonexaminationforthispatient.(7marks)• BMI-ht/wt-REQUIRED• Lossofsubcutaneousfat• Hypotension• Bradycardia• Hypothermia• SignsofCCF• Reducedcapillaryrefill• Hairloss• Teeth-enamellossfromvomiting
• Parotidglandswelling• Insensitivitytopain• Skinsores• Poorhealingwithmalnutrition• Evidenceofselfharm–oftenassociated• Hyporeflexic• Genweakness• Examinationforpossiblealternativecausesforwt
loss-cancers-skin,breast,abdominal
ArapidassessmentnursehasorganisedavenousbloodgaswhichshowsaserumK+levelof2.2.
c. Statethree(3)clinicalfactorsthatwouldleadyoutochooseIVreplacementastherouteofchoice.(3marks)• Extremeweakness• Cardiacarrhythmias• DehydrationrequiringIVtherapy• Vomiting
d. Stateone(1)proandone(1)consfororalandIVrouteforpotassiumreplacement.(4marks)
Route Pros Cons
Oral• Rapidabsorption(chlorvescent)• Moreacceptabletopt• AvoidsrisksofIV
• Unpleasanttaste• Mayrefuseoralintake
Intravenous• Avoidscomplianceissues• TitratabletorepeatVBG
measurements
• OD-incorrectrate-cardiacarrhythmias/death• Painatsite• FastratesrequireCVC
PotentialadditionalQ:Beforeyouimplementyourmanagementplan,sheaskstogetdressedanddischargeherself.
Statefive(5)keyissuesinthissituation.(5marks)• AutonomyvsDutyofCare• DeterminelevelofCompetence• Assessmenthasnotbeencompleted• Reasonsforwantingtoleave• Attempttosecurept’strustandconfidence• Addressthesereasonsifpossible• Seekassistance:NOK,nursing• Empowerptwithoptions• Involuntaryinterventiononlyifindicatedandlegallyempowered
Question3(18marks)
A35yearoldwomanpresentswithsuspectedthyroidstorm.
a. Statefour(4)diagnosticfeaturesofthyroidstorm.(4marks)
• Biochemicalevidenceofhyperthyroidism(↑T4+/-T3and↓TSH)• Temp≥37.8°C• Alteredmentalstate• Cardiovasculardysfunction-egTachycardiaoutofproportiontofever(usually120-140)
NB:nowidelyacceptedabsolutecriteria
b. Listthree(3)likelyprecipitantsforthyroidstorm.(3marks)• UnDx/underRxGraves• Withdrawalofanti-thyroiddrugs• Infection• AMI• DKA• Sx-thyroidorelsewhere• Iodineadministration• Thyroxinetoxicity• Vigorouspalpationofthethyroidgland
c. Listthree(3)medicationsthatmaybeusedforthispatient.Foreachmedication,stateone(1)reasonwhythismedicationisused.(6marks)
Medication
(3marks)
Whyisthismedicationused?
(3marks)
BBlocker-propranololistheusualagent control the symptoms and signs induced by increased adrenergic tone Blocks central and peripheral
thionamide block new hormone synthesis
iodinated radiocontrast agent inhibit the peripheral conversion of thyroxine (T4) to triiodothyronine
(T3)Glucocorticoids reduce T4-to-T3 conversion, promote vasomotor stability, and possibly
treat an associated relative adrenal insufficiency
Bile acid sequestrants decrease enterohepatic recycling of thyroid hormones
d. Listone(1)medicationthatisspecificallycontraindicatedinthyroidstorm(1mark)• Aspirin(displacesT4fromthyroglobulin)
e. Otherthanintravenousfluidsandoxygen,listfour(4)non-medicinaltreatmentsthatmaybeutilisedforthispatient.(4marks)
• Externalcooling• DCcardioversionforarrhythmias• Peritonealdialysis• Plasmapheresis• Charcoalhaemoperfusion
Question4(12marks)A64yearoldmaleisinvolvedinahighspeed,rollovermotorcarcollision.Hewasunrestrained.Onambulancehandoverhehasobviousbilateralfemur#,widespreadchestandabdominalbruisingandasuspectedpelvicfracture.Timefrominjuryonarrivalis90minutes.Hehasreceived4LNsprehospital.Hisobservationsonarrivalare:BP60/30 mmHgHR145bpmRR30bpmSats90%15Lvianonrebreathermask
a. BasedontheCRASH-2studyfindings,statefour(4)pointsrelatingtotheuseofTranexamicacidforthispatient.(4marks)
• Indicatedasheisinhaemorrhagicshock(mostlikely)/atriskofseverehaemorrhage• Shouldbegivenasearlyaspossible• 1gover10min,then1gover8hr• Mostbenefitinsevereshockgroup-applicabletothispt• Notexpectedtoaffectbloodrequirements• NotexpectedtoaffectneedforOT
b. Statetwo(2)criticismsfortheCRASH-2study.(2marks)
• TXA2 group got more FVIIa• most benefit appeared to be in the severe shock group• many of the centers were in developing countries
Youaresituatedinanoutersuburbanhospital.Afterdiscussionwiththeregionalretrievalservice,itisdecidedtotransferthepatienttoatraumacentre30minutesbyroad.ItisrequestedthatyouarrangeplacementofaREBOApriortotransport.
c. WhatisREBOA?(1marks)• Resuscitativeballoonocclusionoftheaorta• Insertionofanintra-aorticballoontoreducedistalbloodflow
d. Listthree(3)featuresofthispatientthatmaysupporttheuseofaREBOA.(3marks)
• Haemorrhagicshock• Suspectedseverepelvicinjury• TimetodefinitiveRx<60-90minutes
e. Ingeneral,listtwo(2)specificindicationsforaZone1REBOA.(2marks)
• Highgradeinjuryofliver(≥Grade3)• Highgradeinjuryofspleen(≥Grade3)• Highgradeinjuryofkidney(≥Grade3)• Mesentericdisruption• Namedabdominalvesselinjury
CRASH-2 Trial Collabaorators (2010) “Effects of tranexamic acid on death, vascular occlusive events, and blood transfusion in trauma patients with significant haemorrhage (CRASH-2): a randomised, placebo-controlled trial” Lancet 276:23-32
• DB MCRCT (274 hospitals, 40 countries) • n = 20,211 adults within 8 hours of injury (blunt and penetrating) at risk of severe haemorrhage or in
haemorrhagic shock • Intervention: tranexamic acid 1g over 10 min then 1g over 8h IV • Control: placebo • Primary outcome: all cause mortality within 4 weeks of injury (bleeding, vascular occlusion – MI, CVA, PE,
MOF, HI, other) • secondary outcomes: vascular occlusive events (MI, CVA, PE, DVT), surgical intervention (neurosurgery,
thoracic, abdominal, pelvic), receipt of blood transfusion, units of blood products transfused, degree of dependency, FVIIa use and GI bleeding
• Results: -> all cause mortality reduced in the TXA2 group -> decreased mortality due to bleeding (RR 0.85) (which was 35% of deaths) -> trend toward more vascular occlusive events in placebo group -> no difference in transfusion and need for surgery -> trend towards early treatment being more effective -> NNT 65, ARR 1.5%, RR 0.91
• Commentary and criticisms: — TXA2 group got more FVIIa — most benefit appeared to be in the severe shock group — many of the centres were in developing countries CRASH 2 a priori subgroup analysis 2011
• benefit for tranexamic acid was greater if given early • NNT 125 (RR 0.68) for death from bleeding if given within 1 hour • benefit up to 3 hours post-injury • causes harm if given later than 3 hours
ThisarticlepublishedinJTrauma(74(6),May2013,p1587–1598)givesanexcellentsummaryofthecurrentevidenceasof5/2013Summary:WhatDoWeKnow?
• TXAisassociatedwitha1.5%reductionin28-dayall-causemortalityinadulttraumapatientswithsignsofbleeding(SBP<90mmHg,heartrate>110beatsperminute,orboth,within8hoursofinjury)inalargepragmaticprospectiverandomizedplacebo-controlledtrial.
• Whatiscriticalisthemodesteffectontheoverallpopulation:All-causemortalitywas“significantly”reducedfrom16.0%to14·5%(NNT,67).Theriskofdeathcausedbybleedingoverallwas“significantly”reducedfrom5.7%to4·9%(NNT,121).
• TXAsignalforbenefitwasinthemostsevereshockgroup(admissionSBP<=75mmHg),28-dayall-causemortalityof30.6%fortheTXAgroupversus35.1%fortheplacebogroup(RR,0.87;99%CI0.76–0.99).
• 1,063deaths(35%)werecausedbybleedingintheCRASH-2Trial.• TXAhadgreatestimpactonreductionofdeathcausedbybleedinginthesevereshockgroup(SBP<=75mmHg)(14.9%vs.18.4%;
RR,0.81;95%CI,0.69–0.95).• EarlyTXA(<=1hourfrominjury)wasassociatedwiththegreatestreduction(32%reduction)indeathscausedbybleeding(5.3%vs.
7.7%;RR,0.68;95%CI,0.57–0.82;p<0.0001).• TXAgivenbetween1hourand3hoursafterinjuryalsoreducedtheriskofdeathcausedbybleeding(4.8%vs.6.1%;RR,0.79;95%CI,
0.64–0.97;p=0.03).• TXAgivenafter3hoursafterinjurywasassociatedwithanincreasedriskofdeathcausedbybleeding(4.4%vs.3.1%;RR,1.44;95%
CI,1.12–1.84;p=0.004).• TXAhadnoimpactonTBIoutcomes,butthestudywaslimitedbysmallsamplesize.• TXAtreatmentisnotassociatedwithanincreasedriskofvascularocclusiveevents.
WhatIsStillUnknown?
• WhetherTXAhasanyimpactontraumaoutcomeswhendamage-controlresuscitationorMTprotocolsareused;• ThemechanismbywhichTXAreducedmortalityintraumaintheCRASH-2Trial.Fibrinolysisassessmentandcoagulationtestingwere
notpartofthestudydesign,anddeterminationoftimetocessationofhemorrhagewasnotrequiredinthestudy;• WhetherfibrinolysistestingshouldbeperformedbeforeconsiderationofTXAtreatment;• WhatistheoptimaldoseandtimingofTXAintrauma;• WhetherotherantifibrinolyticagentscouldbesubstitutedforTXAuseintrauma;• WhetherTXAisassociatedwithhigherseizureratesintraumaorTBIpatients.Increasedpostoperativeseizureshavebeenreported
incardiacsurgerywithTXAdosesthatare2-foldto10-foldhigherthanthoseusedinCRASH-2.75–80Theseseizureshavebeenassociatedwithanincreasedincidenceofneurologiccomplications(deliriumandstroke),prolongedrecovery,andhighermortalityrates.AproposedmechanismforseizuresisTXA-mediatedinhibitionofglycinereceptorsasapotentialcauseofneurotoxicity.81,82ArecentwarninghasbeenaddedtotheFDAdruglabel:“Convulsionshavebeenreportedinassociationwithtranexamicacidtreatment.”83
ARationalApproachforTXAuseinTrauma• Inadulttraumapatientswithseverehemorrhagicshock(SBP<=75mmHg),withknownpredictorsoffibrinolysis,orwithknown
fibrinolysisbyTEG(LY30>3%);
• OnlyadministerTXAiflessthan3hoursfromtimeofinjury;• TXAadministration:1gintravenouslyadministeredover10minutes,then1gintravenouslyadministeredover8hours.
MATTERSstudy• retrospectiveobservationalstudy(i.e.lowqualityevidence)• benefitfoundfortranexamicacidinthemilitarysetting(CampBastion,Afghanistan)• includedpatientswhorequiredtransfusionandweregiventranexamicacid• decreasedamountoftransfusedPRBCsneedediftranexamicacidgiven
MATTERS2study• retrospectiveobservationalstudy(i.e.lowqualityevidence)• militarysetting(CampBastion,Afghanistan)• synergisticdecreaseinmortalitywithtranexamicacidandcryoprecipitate• mortalitywas14.4%forTXA+cryovs28.8%ifneitherused• despitehigherISSscores(severityofinjury)intheinterventiongroup
TheMATTERsIIstudyexpandedthesamplesizeoftheMATTERsIstudytofurtherevaluateTXAandtraumaoutcomes.Areviewof1,332patients(identifiedfromprospectivelycollectedUKandUStraumaregistries)whorequiredoneormoreRBCunittransfusionwereanalyzedtoexaminetheimpactofcryoprecipitate(CRYO)inadditiontoTXAonsurvivalincombatinjuredpatients.DespitegreaterISSsandRBCtransfusionrequirements,mortalitywaslowestinpatientswhoreceivedTXA(18.2%)orTXA/CRYO(11.6%)comparedwithCRYOalone(21.4%)orno-TXA/CRYO(23.6%).LogisticregressionanalysisconfirmedthatTXAandCRYOwereindependentlyassociatedwithasimilarlyreducedmortality(OR,0.61;95%CI,0.42–0.89;p=0.01andOR,0.61;95%CI,0.40–0.94;p=0.02,respectively).ThecombinedTXAandCRYOeffectversusneitherinasynergymodelhadanORof0.34(95%CI0.20–0.58;p<0.001),reflectingnonsignificantinteraction(p=0.21).
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Question5(11marks)A75yearoldmanpresentswithpalpitations.
Onexamination:BP 140/60mmHgsupineRR40/minOxygensaturation88%on6LviaHudsonmaskGCS15
a. WhatistheECGdiagnosis?(1mark)
• Multifocalatrialtachycardia(MFAT)
b. Statethree(3)abnormalitiesonthisECGtosupportthisdiagnosis.(3marks)• Atleast5atrialfoci(≥3fordiagnosis)• Ventricularrate>100(variable130-170here)• VariablePP,PR,RRintervals
c. Listfour(4)likelycausesfortheseECGchanges.(4marks)
• Severeairwaysdisease• Digitalistoxicity• Theophyllinetoxicity• LargePE• Severehypoxia• Diabetes
d. WhatistheclinicalrelevanceofthisECGdiagnosis?Statethree(3)pointsinyouranswer.(3marks)
• Usuallyassociatedwithseriousillness/respiratoryfailure• ResolveswithRxofunderlyingdisorder• Poorprognosticsign(60%inhospitalmortality,meansurvival1yr-duetounderlying
disease,notarrhythmiaitself)
Question6(12marks)A32yearoldman,JohnSmith(UR123456),presentstoyouremergencydepartmentfollowingahighpressureinjurytohisleftmiddlefinger,1hourago. (SameptatSxshownbelow)
a. Listthree(3)pathophysiologicalmechanismsforharmfromthismechanismofinjury.(3marks)• Directtissueinjury/inflammationfrom:
o noxiousmaterialinjectedintopulp/flexorsheaths-progressivenecrosiso chemicalinjury-localanaesthesiao heat-burn
• Ischaemiaasaresultoftissueundermarkedtension• Infection
b. Listthree(3)factorsassociatedwithapooroutcomefromthisinjury.(3marks)
• Fuel/paintinjected(70%amputationrate)• Distalfingertipinjuries• Lowviscosityagents(greatertissuespread/penetration)• Contamination/wastewater• Delaytooperativeintervention• Placementofringblock(increasestensionintissueandworsensischaemia)
Youdecidetoreferthepatientafteryourcare.c. UsinganISBARapproach,listfive(5)piecesofinformationthatyouwouldpassontothereceivingDoctor.(5marks)
• Identify-Myname,Emergencyregistrar,PtJohnSmith32MUR123456(Whoyouareandwhatisyourrole?)
(Patientidentifiers-atleast3)(2marks)• Situation-Highpressureinjury,toLmiddlefinger (Whatisgoingonwiththepatient?)• Background-Detailsofinjectant,1hourago (Whatistheclinicalbackground/context?)• Assessment-Criticallyurgent(digit/limbthreatening)problem (WhatdoIthinktheproblemis?)• Recommendation-UrgentreviewrequiredwithaviewtourgentSx.(Whatwouldyourecommend?)
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HistoricalAspectsRees1,in1937,wasthefirsttodescribeahighpressureinjectioninjuryandnotethepotentialseverityoftheinjury.Hedocumentedtheclinicalcourseofa47yearoldmechanicwhohadadieselfuelinjectioninjury.Thepatientinitiallypresentedwithanapparentlyinnocuousinjury.Hedevelopedpainafterafewhoursandthendevelopedasystemicresponsetotheinjurywithlymphadenitis,leucocytosisandfever.Hisfingerprogressedtogangrenewithinaweekandrequiredrayamputation.In1941,MasonandQueen2describedthreephasesthatdefinethenaturalhistoryofhighpressureinjectioninjuries(early,intermediateandlate)andtheirdescriptionisstillinusetoday.TheprognosisfortheseinjurieswastraditionallysopoorthatKaufman3in1968advocatedamputationofthedigitastheprimarytreatment.HistoryofIllnessManytypesofhighpressureinjectiondevicearenowinfrequentusewithinanindustrialsetting.Theminimumpressurerequiredtobreachintacthumanskinis100psior7x105NM2(7bar)4butpressuresmayexceed2500bar(35500lbs/in2).Mostinjuriesarecausedbygreaseguns,spraygunsanddieselinjectorsbutpneumatichoses,plasticmouldingorcementinjectors,hydrauliclines,greaseboxes,vaccinationequipmentandoilrigdrillingdevicescanallproducetheseinjuries.Thesedevicesareused,amongstotherthings,inpainting,lubrication,cleaning,andmassfarmimmunization.Adiversespectrumofsubstancesmaybeinjectedwhichvaryintheirlocalandsystemictoxicity.Theseincludepaint,paintthinner,oil,dieselfuel,grease,hydraulicfluid,water,plastics,cementorbiologicalvaccines.EpidemiologySchooetal5estimatedtheincidenceofhighpressureinjectioninjuriestobe1in600handinjuriesattendinganemergencydepartment.Therearenootherestimatesofitsincidenceintheliteraturealthoughitiscertainlyanuncommoninjury,albeitaseriousone,particularlyifitssignificanceisinitiallyunrecognised.Highpressureinjectioninjuriespredominantlyaffecthealthyyoungmen,sincetheyarelargelyoccupationalinjuries.Itisusuallythenondominanthandthatisaffected,withtheindexfingerbeingthecommonestdigitaffected.However,anyareaofthebodycanbeaffectedandtherehavebeenreportsofinjuriestoallregionsofthebodyincludingthescrotum6.Injuriestothedigitstendtobeseriousasrapidinfusionofalargevolumeoffluidintoasmallclosedspaceleadstoarapidincreaseininterstitialpressurewhichmaycompromisethecirculationtothedigit.Greasegunsarethemostcommontypeofequipmentinvolvedintheseinjuriesandthismaybebecauseitsusersarelesslikelytobeskilledthanthosewhouseotherhighpressuredevices7.PathophysiologyMasonandQueendividedtheresponsetohighpressureinjectioninjuryintothreephases:theearly,intermediateandlatephases.Theearlyresponseisofswelling,numbnessandpossiblevascularinsufficiencyduetoacombinationofmechanicalandchemicalfactorsthatmayactsynergistically.Ininjuriesproducingagreaterinflammatoryresponse,suchaspaintthinnerinjuries,chemicalinflammationismorelikelytobecausativeofvascularcompromisethanthemechanicaleffect.Inotherinjuriesthepredominantfactorisuncertain.Thevolumeoftheinjectedsubstanceitselfactstogetherwiththelocalinflammatoryresponsetoraisetheinterstitialpressure.Thismayresultinvascularocclusioneitherasadirecteffectofthefluidvolatisingorasaresultofvenousorarterialcompression.Somematerialsthatproducelocaltissuedestructionandnecrosismaydosobylipiddissolutionorbyproteincoagulation.Dickson8suggestedthatinpaintthinnerinjuries,theseverechemicalinflammationwassecondarytothealkylbenzinesinwhitespirit.Superaddedinfectionmightfurthercompromisetissueviabilityandextendthezoneoftissuenecrosisandgangrene.Intheintermediatephase,thereistheformationofforeignbodygranulomataoroleomata.ThiswasfirstdescribedbyHessein19259whonoteditinRussianrecruitswhoinjectedthemselvessubcutaneouslywithgreasetotrytoavoidnationalservice.Thesearenodulartumourswhicharetheresultofaforeignbodyreactiontotheinjectedmaterial.Widespreadvesselthrombosisoccurswithaninflammatoryreactionintheadventitiaandthrombosisofthevasavasorumandvenaecomitantes.Thisproducescoagulativenecrosisoftheskinand
subcutaneoustissue.Fatislostfromfatlocules.Damagetothetendonsheathandperineuralfibrosisresultsinlatefibrosisandcontracture.Oleomatamaypersistunchangedforyearsbuttheassociatedfibrosismayaffecthandfunction.Thelatephaseisrarelyseenindevelopedcountries.Heretheskinovertheoleomatabreaksdown,producingpersistentulcersandsinuseswhichdischargegreaseandepithelialdebris.Theybecomesecondarilyinfectedandsoincreaseinflammatorychangesintheskin.Thereisatheoreticalriskofmalignantchangeintheselongstandingsinuses.PresentationHistoryThehistoryshouldalertthecliniciantotheseverityoftheinjury.Thepatientmayeitherbeawarehimselfoftheseverityoftheinjuryormayhavebeensenttotheemergencyroombyhisemployerwhoshouldhaveoperatinginstructionsfortheequipmentbeingusedandguidelinesastowhentoseekattention.Unfortunately,theclinicianwhoisunawareofthepotentialconsequencesoftheseinjuriesmayunderestimatethemanddismissthemastrivial.Takinganadequatehistoryofthepressureatwhichtheequipmentwasoperating,thetimeoftheinjuryandthevolumeandnatureofthematerialitcontainedwillprovidethediagnosisandsuggestthelikelyprognosis.PresentingcomplaintsThepatientmaypresentwithoutanysymptomssincepainisnotalwaysinitiallypresent.Afewhoursaftertheinjury,thereisincreasingpainandthepatientmaycomplainofsomenumbnessanddiscoloration.MechanismofInjuryManystudiessuggestthatinexperienceinoperatingtheequipmentisafactor.Kaufman3foundthatmostoftheinjurieswereinworkerswhohadoperatedthisequipmentforlessthansixmonthsalthoughtheymayhaveoperatedsimilarlowpressureequipmentwheretestingthenozzleontheendofthefingerwassafe.Typicallyinjuryoccurswhenthegunisbeingcleaned,thesafetynozzlehavingbeenremoved,orwhentestedafterreassemblyorafterthenozzlejams.PhysicalExaminationInspectionEarlysignsareminimal,usuallyonlyapuncturewoundatthesitewheretheskinhasbeenbreachedandoozingoftheinjectedsubstancefromthewound.Theremaybesomelocalswelling.Occasionallythepatientmaypresentearlywithadigitwhichispale,coolandnumbshowingobviousvascularcompromise–theseinjuriesdopoorlyevenwhenappropriatelytreated.AdigitalAllen’stestmaydemonstratedigitalarterythrombosisbutthisisunnecessary,anditmaybeinadvisabletoperformthistestinthissituation.Ifthepainappearsdisproportionatetothatexpectedoftheinjury,clinicalevidenceofraisedcompartmentpressuresshouldbesought.Ifacompartmentsyndromeispresent,painwillbeworsenedbypassivelystretchingofthemusclesinthatcompartment.Testtheanteriorforearmcompartmentbypassivewristandfingerextension,thewristextensorsandbrachioradialismusclebypassivelyflexingwristinulnardeviation,andthedorsalforearmcompartmentbysimultaneouswristanddigitalflexion.Withinthehand,testtheadductor,thenar,hypothenar,anddorsalandvolarinterosseicompartmentsandexamineforanacutecarpaltunnelsyndrome.Laterpresentationmayshowgreaterswellingandstiffnessofthedigitsorabluishdiscolorationifthevenouscirculationiscompromised.Ifthepatientdoesnotpresentfordaysorweeks,theremaybegangrenepresentoraswollen,stiffdigitwithsubcutaneoustumours,ulcerationordischargingsinusespresent.Ifleftunattended,thesinusesbecomesecondarilyinfectedincreasinginflammatorychangesandfibrosisandproducingmorestiffness.Thereisatheoreticalriskofmalignantchange,withsquamouscellcarcinomadevelopingwithinthechroniculcers.PalpationThedigitmaybetendertotouchalongthepathoftheinjectedmaterial.Sensationmaydecreasewithswellingsotheremaybereducedtwo–pointdiscrimination.Capillaryrefillwillbebriskifthereisvenouscompromiseorsloworabsentifthereisarterialcompromise.Wherelargeamountsofairareinjected,crepitusmaybedemonstrable.Laterthepatientmayshowalowgradefever.Systemicsymptomsareotherwisedependentonthesubstanceinjected,withacuterenalfailurebeingreportedafterinjectionofwaxsolventandacuteleadintoxicationafterinjectionoflead-basedpaint.QuantificationAssessmentoftheseverityoftheinjuryisfromacombinationofhistory,physicalandoperativefindings.Theseveritydependsonthenatureofthematerialconcernedanditsdistribution.Thenatureofthematerialincludesitstoxicity,itsviscosityanditsvolume.Thedistributiondependsonthesiteofinjection,depthofpenetration,anatomicalplaneinwhichspreadoccursandtheejectionpressure.Someofthesefactorsareinterdependent.ToxicityofInjectedMaterialThetoxicityofthematerialisdependentonitschemicalcomposition.Lipidsolublematerialsproduceagreaterinflammatoryresponseandtherefore,greatertissuedestruction,thangrease.Theywillcauselipiddissolutionevenwhennotunderpressure.
Fig2(a).ExtentofproximalsolventspreadafterhighpressureinjectiontoindexfingerFig2(b)Outcomeofinjury
Paintsolventsaremoretoxicthaneitherpaintordieselfuel,resultinginamputationin80%ofcasesinoneseries5.Paintiscomposedofsolvents,vehiclesandpigmentsandsometimesbacterialcontaminants,allofwhichcontributetotheinflammatoryresponseandtissuedestruction.Greasecauseslessdestructionandhaslesssevereinflammatoryresponsesotheriskofamputationinthesameserieswasonly20%.Waterandairinjuriesareusuallyrelativelybenign.Evenso,waterinjectioninjuriescanmimicgunshotinjuriesintheirtissuedestructionandproduceacompartmentsyndrome.Estimationoftheirseverityshouldnotbebasedpurelyontheappearanceoftheexternalwound.Bacterial,fungalorchemicalinoculation(withsewageoroillubricant)inwaterjetinjuriesmayfurthercomplicatetheclinicalpicture.Highenergygasinjectionfromfiringhandgunblankroundsatcloserangecancauseseriousinjuryandgasembolismanddeathhavebeenreported10.ViscosityThemoreviscousthematerial,thelessitwillspread.Paint,therefore,doesnotdisperseasfaraspaintsolventswhich,therefore,affectagreatervolumeoftissue11.SiteOncethematerialisinjected,ittravelsuntilitmeetsresistance.Kaufman7usinginjectionsintocadaverhandsdefinedclearlytheexpectedcourseofthematerialaccordingtothesiteofinjection.Thebones,tendonsandflexorsheathactaspointsofresistancewhichdeflectthematerialcausingittospreadsuperficiallythroughthesofttissues3.Deeperspreaddependsontheanatomicalsiteofinjection.Ifthesiteofpenetrationisattheinterphalangealjointcreasewheretheflexorsheathisweak,thesubstancewilltravelwithinthesheathandmaythereforespreadmoreproximallydirectlyintothepalmorwrist.Spreadwithinthesheathdoesnotappeartoaffecttheprognosis12.Withpressuresexceeding5-10000psi,thetendonsheathwillalwaysbeatriskofpenetration.Theanatomicalarrangementofradialandulnarbursaemakesproximalspreadintothewristmorelikelyiftheinjectionsiteisintothelittlefingerorthumb.
Diagram1.SimplificationofflexorsheathanatomyinthehandIfthepuncturewoundiseccentric,thedorsalsurfaceofthedigitislikelytobeextensivelyinvolved.Materialinjectedintothethenarorhypothenarspacesislikelytoremainthesecompartmentsbutmayinvolvetheintrinsicmuscles.Intheexperimentalsituation,injectionintothemidpalmarspacefailedtoshowextensionproximallyintothewristbutextensiontothedorsumdidoccur7.Injectiondistallyinthedigitscarriesaworseprognosis,possiblyrelatedtothesmallervolumeofthedigitsandtheirlackofdistensibilityproducingagreaterriseininterstitialpressure13.Kaufmannequatedtheamountofenergyproducedinagreaseguninjurytoadigittoa1000kgweightfallingfromaheightof25cm.Thevelocityofthejetofmaterialemittedmaybeupto1550mph(2500km/hr)andthetheoreticalkineticenergydissipatedonimpactmaybecalculatedfromtheformula,KE=1/2mv2.Therefore,thedigits,havingasmallermasswillhaveagreateramountofkineticenergytoabsorbandwillhencesufferaworseinjurythanmoreproximalparts.EjectionpressureGreasegunsproducepressuresof350-700bar.Sprayguns,thatareusedintheapplicationofpaint,lacquer,semifluidcement,hydraulicfluidsandsolvents(paintthinner,turpentineorgasoline),operateintherangeof200-500baranddieselfuelinjectorsfrom140-400bar.Watergunsoperatebetween400-550bar14.VolumeThevolumetoleratedatdifferentsitesofinjectionisvariable.Thedigitscanonlytolerate1ccwhilstthepalmmaytoleratemorethan5cc3.Chickenvaccineinjury,despitebeinginanoil-basedcarrier,doesnotappearasdangerousaspigvaccineperhapsduetotheirdifferentrespectivevolumes(0.2ccversus2cc)15.Agreatervolumeatthesamesiteisrelatedtopoorerfunctionalresults16.InvestigationsLaboratoryAfterafewhoursandparticularlywiththeinjectionofoilbasedsubstances,aleucocytosismaydevelop.Sometimeslaboratoryanalysisofthefluidmayhelpingaugingprognosisforrecoveryorbacteriologyinassessinglikelyinfectingorganisms.X-raysRadiographsarenotessentialandoftenaddlittletotheexamination.Plainradiographsmaygivesomeideaofthedegreeofdispersionofthesubstanceifitisradio-opaqueoriftheydemonstratesubcutaneousemphysema.Thismayassistinplanningtheoperativeapproach.Serialradiographsmaybeperformedintraoperativelytoensureremovalofalloftheinjectedmaterial.
Fig4.Lateralradiographshowingextentofproximalspreadofradio-opaquepaintindigitClassificationTheonlyclassificationusedisthatofearly,intermediateandlatestagesofthediseaseasdescribedbyMasonandQueen2.Classifyingtheseinjuriesinrelationtothesubstanceinjectedwouldbereasonableforthepurposesofbothtreatmentandprognosis.Themostobviousgroupingwouldbeforoilbasedsubstances,solventsandpaintstobegroupedtogether,allrequiringaggressivedebridementandmedicalmanagement,greaseinjuriestoformanintermediategroup,allrequiringaggressivedebridementbutnotnecessarilyrequiringantibiotics,andwaterandairinjectioninjuriestoformaseparategroupwhichmaybesuitableforconservativemanagement..TreatmentMedicationsanddosesAntitetanustoxoidshouldbeadministeredifthepatientisnotcoveredbuttetanusimmunoglobulinisonlyrarelyindicated.Acourseofantibiotics,usuallyacombinationofacephalosporinandanaminoglycoside,iscommonlygivenalthoughtheevidenceforthisispoor17.Inanexperimentalmodel,allorganicdyesandallsolventswerebacteriocidal,asweresomeofthevehiclesusedinpaintalthoughtheinorganicdyeshadnoantibacterialaction18.Thoseagentsmostlikelytocreateagreaterinflammatoryresponsewerealsomostlikelytobebacteriocidal.Thisisweighedagainsttheknowledgethatthepresenceofaforeignmaterialinawoundwillimpairthebody’sabilitytoresistinfectionandevensub-infectivequantitiesofbacteriamayresultinfrankinfection,especiallywherethereisanyevidenceofvascularcompromise.SomeauthorssuggesttheuseofantiplateletagentssuchasaspirinandlowmolecularweightDextrantoimprovethemicrocirculationtothedigitbutthisisnotroutinepractice.Nonsteroidalanti-inflammatorydrugsmayhavesomeeffectatreducingtheinflammatoryresponsebutanyeffectisnotdramatic3.Whethersteroidsareofanytherapeuticbenefitisdisputed.Thereisevidenceofbenefitinanimalmodels18,13.Invivo,someauthorsrecommendtheiruseroutinely19,othersusethemforallexceptgreaseguninjurieswherethereisminimaltissueextension12andothersconsiderthemcontraindicatedduetotheirdepressionoftheleucocyteresponse20Regionallocalanaestheticblockademaybeemployedtoimprovethemicrocirculationbyproducingperipheralvasodilatation.Digitalblocksshouldbeavoidedastheymaycompromisethemicrocirculationbyincreasingtheinterstitialpressure.SplintsSplintageisusedtoreducejointcontractureandprovidethebestpositionfromwhichtomobilize.Thesplintneedstobeforearmbasedandmaintainthehandinanintrinsicplusposition.Nightsplintagemayneedtocontinueforsomemonthsfollowingsurgery.PhysicalTherapyHandtherapyisrequiredinallcaseswhethertreatedsurgicallyorconservatively.Eventhosewhopresentlateandrequireamputationarelikelytorequirehelpwithmobilizationoftheirhand,astheyarefrequentlyleftwithresidualstiffnessinadjacentdigits.ConservativemanagementAsarule,theseinjuriesrequireexpeditioussurgicalinterventionbutthereareinstanceswhereconservativemanagementmaybeappropriate.Thedecisionshouldbemadeonacasebycasebasisandonlybyanexperiencedhandsurgeon.Thosecasesthatmaybeabletobemanagedwithoutsurgicalinterventionarethosewherethematerial,siteandfindingsarefavourable21.Thefewcasesintheliteraturewherechickenvaccinehasbeeninjectedshowthat,althoughinanoilcarrier,itisusuallywelltolerated15.Airandwaterinjectioninjuriesarealsorelativelybenign22,23andmaybesometimestreatedconservativelywithelevation,splintagewithorwithoutantibioticsandsteroids.Waterguninjuriesonlyneeddecompressioniftherearesignsofacompartmentsyndrome14,24.Evenifadecisionismadetotreatconservatively,thesepatientsstillrequireadmission,carefulobservationandfollow-up.Theirdigitstendtoremainswollenforsomeweeksandtheirhandsmaybecomeextremelystiff.SurgicalmanagementSurgicalexplorationshouldbethemainstayofmanagementforthisconditionandshouldoccurwiththesameurgencyasforacompartmentsyndrome.SurgicalsurprisesTheunwaryareespeciallylikelytounderestimateboththeseverityandtheextentofthisinjury(seeFig7.forthepotentialforspreadintheseinjuries).Thesurgicalapproachshouldbeplannedsothatproximalextensionofthewoundissimple.
PrognosisandoutcomesofsurgeryMultiplefactorsdeterminetheoutcomeoftheseinjuries.Deathhasbeenreportedafterabdominalhighpressurewaterinjuriesthathavecausedcaecalperforation25andafterairembolismfromhighpressureairinjection10.Thereisamorbiditywhetherornotthedigitissalvaged.Digitalamputationratesintheliteraturevaryfrom16%20to48%5.Itispresumedthattheprognosisisworsenedifthereisanydelaytosurgery.Severalauthorshavesuggestedalowermorbidityifthetimefrominjurytodecompressionislessthantenhours26,27,17.Othersstudies13havebeenunabletoconfirmthisandinsomethosereachingsurgeryfirstappearedmorelikelytoendinamputation28,12.InSchoo’sseries,16outof21thatwereamputated,weredebridedwithin24hoursoftheinjuryandteninlessthansixhours.Thismaybeduetothegreaterseverityoftheirinjuries.Thetimefactormayplaylessofaroleinthoseinjurieswherechemicallyinducedinflammationratherthanpressureistheprimarynoxiant. Theriskofamputationvarieswiththematerialinjectedwithamuchworseprognosisforpaintandpaintthinnersthangreaseprobablyduetoadirecttoxiceffectonthetissues12,29.Schooetal5demonstratedan80%amputationratewithpaintsolventscomparedtoanoverallamputationrateof48%ifallmaterialswereincluded.Gelbermanetal13had83%amputationratewithpaintinjuriescomparedto24%withothermaterials.Thehighertheinjectionpressureoftheappliancethemorelikelyamputationwillresult.InthereviewbySchoo5,allcaseswheretheejectionpressurewas>7000psi(500bar)culminatedinamputation.Thisonlyconsistedofthreecasesofthe127reviewedsoitisimpossibletoconcludethatinjuriesataspecificpressureorgreatershouldalwaysbeamputated.Patientswhoshowevidenceofinitialvascularcompromisearelikelytoresultinamputation12.Pintoetal20hadahighdigitsalvageratewhichheattributedtotimelyaggressivedebridement,openwoundpackinganddelayedprimaryclosureratherthananattempttoclosethewoundprimarily.Thevolumeofinjectedsubstancemaycontributetotheriskofamputationbutthisisdifficulttoascertainasonlyanimalvaccinescomeinasetvolume27.Itisbelievedthatthegreatervolumeofmaterialinjected,theworsetheprognosisbutthisisdifficulttoproveexceptinthecaseofanimalvaccineswhereasetvolumeisgiven.Injuriestothedigitswherethereislittleroomfordispersaldoworsethanmoreproximalinjuriesthatcantolerateagreatervolumeofinjectedmaterial.Littleworkhasbeendonedocumentingthequalityoffunctionofthehandfollowingdigitsalvage.Inoneseries,92%returnedtoworkwith62%whowereconsideredtohavefunctionalhands20.Wherethedigitwassalvaged,therewasacorrelationbetweenthematerialinjectedandthetimetoreturntoworkwithgreaseguninjuriesinvolvingalongerrehabilitationperiod5.Christodoulou28,inhisstudyoffifteenpatientsanaverageof73monthspostinjury,foundthatthreeofthesixwhohadhadamputationshadchangedoccupationOnlyoneoftheninewithsalvageddigitshadalteredhiswork.Incomparisontotheuninjuredhand,gripstrengthwasdecreasedby15%,lateralkeypinchby23%,andchuckgripby25%.Dynamicmusclepowerwasreducedby27%.Sensoryevaluation,whereitwaspossible,showedadecreaseinsensibilitywithonlyonepatienthavingnormalsensation.Sevenhaddiminishedlighttouch,threehaddiminishedprotectivesensationandonehadlossofprotectivesensation.OutcomesComplicationsInfectionmayoccurdespiteantibiotictreatmentandparticularlywhennecrotictissueispresent.Itmayactsynergisticallywithotherfactorstoincreasethelikelihoodofamputationor,ifthedigitissaved,toprolongswellingandstiffnessandtherefore,theperiodofrehabilitation.Mostauthorsgiveantibioticsroutinelybutreportedinfectionratesvaryfrom11.5%13to60%20.Thisserieshadalowrateofdigitamputationbutinretainingdigitstheremayhavebeenmoretissuewithcompromisedvascularitywhichmayhavecontributedtothishighinfectionrate.InfectionsarecommonlyduetoStaphylococcusepidermidisoraureus,Pseudomonassp.orarepolmicrobial.
Question7(12marks)A32yearoldmaleisinvolvedinarollovermotorcarcollision.HeisknowntobetakingaNOAC.a. Underwhatcircumstanceswouldyoutakemeasurestoreversetheactionofthe
NOAC?Listtwo(2)circumstances.(2marks)• Medicationtaken<12/24ago+• Clinicallysignificantlifethreateningbleeding
b. WhatistheroleofcharcoalinthereversalofaNOAC?Statetwo(2)pointsinyour
answer.(2marks)• Indicatedforallclinicallysignificantbleeds• <2/24(upto4/24insomerecommendations-Apixabanupto6/24,
Rivaroxabanto8/24)
c. WhatistheroleofdialysisinthereversalofaNOAC?Statetwo(2)pointsinyouranswer.(2marks)
• Dabigatranonly-noroleinrivaroxiban/apixaban(highlyproteinbound)• Lifethreateningbleeding• Renalfunctionimpairmentor• aPTT>80sec• orDabigatranlevel>500mg/ml
d. OtherthanPackedcells/wholeblood,statethree(3)agentswhichmaybeusedfor
reversaloftheeffectsofDabigatran.(3marks)• Tranexamicacid• ProthrombinX• Idarucizumab(HumanisedmonoclonalFABfragment-biochemicalreversalin
1/24,clinicalreversalat12/24ie=tot½ofdrug)
e. Whatistheroleofthromboelastographyforthispatient?Statethree(3)pointsinyouranswer.(3marks)
• ReNOAC:o MayhavearoleindetectingandmonitoringNOACactivity(rolestill
evolving)• ReTraumaticinducedcoagulopathy:
o Predictstheneedforbloodtransfusiono Guidetransfusionstrategy-FFP/Cryoprecipitate/Platelet/TxA2use
ThisresourceisproducedfortheuseofUniversityHospital,GeelongEmergencystaffforpreparationfortheEmergencyMedicineFellowshipwrittenexam.Allcarehasbeentakentoensureaccurateanduptodatecontent.Pleasecontactmewithanysuggestions,concernsorquestions.DrTomReade(StaffSpecialist,UniversityHospital,GeelongEmergencyDepartment)Email:[email protected] November2017
UseofThromboelastography(TEG)forDetectionofNewOralAnticoagulantsJoãoD.Dias,PhD;KatherineNorem,BA;DerekD.Doorneweerd,PhD;RobertL.Thurer,MD;MarkA.Popovsky,MD;LaurelA.Omert,MDReprints:JoãoDias,PhD,HaemoneticsSA,POBox262,1274Signy-Centre,SwitzerlandThisworkwassupportedbyHaemoneticsCorporation,Rosemont,Illinois.
Context.—Theclinicalintroductionofneworalanticoagulants(NOACs)hasstimulatedthedevelopmentofteststoquantifytheeffectsofthesedrugsandmanagecomplicationsassociatedwiththeiruse.Untilrecently,theonlytreatmentchoicesforthepreventionofvenousthromboembolisminorthopedicsurgicalpatients,aswellasforstrokeandsystemicembolisminpatientswithatrialfibrillation,werevitaminKantagonists,antiplateletdrugs,andunfractionatedandlow-molecular-weightheparins.WiththeapprovalofNOACs,treatmentoptionsandconsequentdiagnosticchallengeshaveexpanded.Objective.—Tostudytheutilityofthromboelastography(TEG)inmonitoringanddifferentiatingbetween2currentlyapprovedclassesofNOACs,directthrombininhibitors(dabigatran)andfactorXainhibitors(rivaroxabanandapixaban).Design.—BloodsamplesfromhealthyvolunteerswerespikedwitheachNOACinboththepresenceandabsenceofecarin,andtheeffectsonTEGwereevaluated.Results.—Boththekaolintestreactiontime(Rtime)andthetimetomaximumrateofthrombusgenerationwereprolongedversuscontrolsamplesanddemonstratedadoseresponseforapixaban(Rtimewithinthenormalrange)anddabigatran.TheRapidTEGactivatedclottingtimetestallowedthecreationofadose-responsecurveforall3NOACs.Inthepresenceofanti-Xainhibitors,theecarintestpromotedsignificantshorteningofkaolinRtimestothehypercoagulablerange,whileinthepresenceofthedirectthrombininhibitoronlysmallanddose-proportionalRtimeshorteningwasobserved.Conclusions.—TheRapidTEGactivatedclottingtimetestandthekaolintestappeartobecapableofdetectingandmonitoringNOACs.TheecarintestmaybeusedtodifferentiatebetweenXainhibitorsanddirectthrombininhibitors.Therefore,TEGmaybeavaluabletooltoinvestigatehemostasisandtheeffectivenessofreversalstrategiesforpatients
OVERVIEWOFCOAGULOPATHYINTRAUMA(FromLITFL)• newtermsthatareinvoguearetrauma-inducedcoagulapathy(TIC)andacutetraumatic
coagulaopthy(ATC)• notsimplya‘dilutionalcoagulopathy’or‘consumptivecoagulopathy’!
PATHOPHYSIOLOGY• TICwasconventionallyconstruedsimplyasdepletion,dysfunctionordilutionofprocoagulant
factors• actuallyanimbalanceofthedynamicequilibriumbetweenprocoagulantfactors,anticoagulant
factors,platelets,endotheliumandfibrinolysis• characterizedbyisolatedfactorVinhibition,dysfibrinogenaemia,systemicanticoagulation,
impairedplateletfunctionandhyperfibrinolysis• exacerbatedbyhypothermia,acidosis(togetherwithcoagulopathytheyform‘thelethaltriad’)
andresuscitationwithhypocoagulablefluidsMANAGEMENT
• earlydetection(ROTEM/TEGholdspromiseforthis)• earlyactivationofmassivetransfusionprotocols• aggressiveproactivebloodproductadministration(PRBCs,FFP,platelets,cryopreciptitate)• preventandtreathypothermiaandacidosis• earlyuseoftranexamicacid• givecalciumifhypocalcaemic• considerFactorVIIifnon-surgicalbleedingandalltheothercorrectableshavebeencorrected
OVERVIEWofThromboelastography(TEG)(fromLITFL)
• Thromboelastographyisaviscoelastichemostaticassaythatmeasurestheglobalvisco-elasticpropertiesofwholebloodclotformationunderlowshearstress
• itshowstheinteractionofplateletswiththecoagulationcascade(aggregation,clotstrengthening,fibrincrosslinkingandfibrinolysis)
• doesnotnecessarilycorrelatewithbloodtestssuchasINR,APTTandplateletcount(whichareoftenpoorerpredictorsofbleedingandthrombosis)
• ThispagedescribesTEG®predominantly,ROTEM®isthealternativeviscoelastichemostaticassaythatiswidelyavailable
METHOD• TEG®measuresthephysicalpropertiesoftheclotinwholebloodviaapinsuspendedinacup
(heatedto37C)fromatorsionwireconnectedwithamechanical–electricaltransducer• Theelasticityandstrengthofthedevelopingclotchangestherotationofthepin,whichis
convertedintoelectricalsignalsthatacomputerusestocreategraphicalandnumericaloutput• pointofcaretest(quick,takesaround30min)• canberepeatedeasilyandcomparedandcontrasted• requirescalibration2-3timesdaily• shouldbeperformedbytrainedpersonnel• susceptibletotechnicalvariations• kaolinandmorerecentlykaolin+tissuefactor(TF)(RapidTEG®)areusedasactivators,NATEM
(TEG®usingnativewholebloodisslower)• othertestsareavailableincludingfunctionalfibrinogen,ameasureoffibrin-basedclotfunction,
andMultiplatewhichevaluatesplateletfunctionUSEIndications
• predictionofneedfortransfusion(MAisausefulpredictorintrauma)• guidetransfusionstrategy
Studiesshowcost-effectivenessandreductioninbloodproductsin:• livertransplantation• cardiacsurgery
Maybeusefulin:• trauma(reductioninbloodproductuseandmortalityincohortstudies)• obstetrics(somedatatoshowthatitmaydecreasetransfusionrates;thisiscontroversial)• earlydetectionofdilutionalcoagulopathy
Hardtointerpretincertainsituations:• LMWH• aspirin• postcardiacbypass• fibrinolysis• hypercoagulability
NORMALTEG
Specificparametersrepresentthe3phasesofthecell-basedmodelofhaemostasis:initiation,amplification,andpropagation
• Rvalue=reactiontime(s);timeoflatencyfromstartoftesttoinitialfibrinformation(amplitudeof2mm);i.e.initiation
• K=kinetics(s);timetakentoachieveacertainlevelofclotstrength(amplitudeof20mm);i.e.amplification• alpha=angle(slopebetweenRandK);measuresthespeedatwhichfibrinbuildupandcrosslinkingtakes
place,henceassessestherateofclotformation;i.e.thrombinburst• TMA=timetomaximumamplitude(s)• MA=maximumamplitude(mm);representstheultimatestrengthofthefibrinclot;i.e.overallstabilityof
theclot• A30orLY30=amplitudeat30minutes;percentagedecreaseinamplitudeat30minutespost-MAandgives
measureofdegreeoffibrinolysis• CLT=clotlysistime(s)
IMPORTANTPATTERNS
TEGASAGUIDETOTREATMENT
• IncreasedRtime=>FFP• Decreasedangle=>cryopreciptate• DecreasedMA=>platelets(considerDDAVP)• Fibrinolysis=>tranexamicacid(oraprotininoraminocaproicacid)
TEG®VERSUSROTEM®Comparison
• Twocommercialtypesofviscoelastictestsareavailable:thromboelastography=TEG®(developedin1948,nowproducedintheUSA)androtationalthromboelastogram=ROTEM®(fromGermany)
• differencesindiagnosticnomenclatureforidenticalparametersbetweenthetwo• TEG®operatesbymovingacupinalimitedarc(±4°45ʹevery5s)filledwithsamplethatengagesa
pin/wiretransductionsystemasclotformationoccur• ROTEM®hasanimmobilecupwhereinthepin/wiretransductionsystemslowlyoscillates
(±4°45ʹevery6s)• resultsarenotdirectlycomparableasdifferentcoagulationactivatorsareused• ROTEM®ismoreresistanttomechanicalshock,whichmaybeanadvantageintheclinicalsetting
EquivalentvariablesforROTEM®• Clottingtime(CT)=Rvalue(reactiontime)• αangleandclotformationtime(CFT)=Kvalueandαangle• Maximumclotfirmness(MCF)=Maximumamplitude(MA)• Clotlysis(CL)=LY30
COMPARISONWITHPLASMACLOTTINGTESTSProsofviscoelastichemostaticassays
• assessmentofglobalhaemostaticpotentialprovidesmoreinformationthantimetofibrinformation
• canreadilydifferentiateacoagulopathyduetolowfibrinogenfromoneduetothrombocytopenia• point-of-care(POC)devicewithrapidturnaroundtimessothatmanyresultsavailablewithin5–10
minofstartingthetestConsofviscoelastichemostaticassays
• variableavailability• markedinter-operatorvariabilityandpoorprecision(UKNEQASdatasuggestscoefficientsof
variancerangingfrom7.1%to39.9%forTEG®and7.0%to83.6%forROTEM®)• mayrequirespecialiststafftoperform
Question8(12marks)
Atwhatheightdoesacutemountainsicknessappearinapersonwhoisnotacclimatisedtoaltitude?(1mark)
• >2500m
a. Listthree(3)examinationfeaturesofapatientwithhighaltitudecerebraloedema.(3marks)
• Lethargy• Alteredconsciousness• Coma• Truncalataxia
b. Listthree(3)managementstepsforapatientwithhighaltitudecerebral
oedema.(3marks)• Immediatedescent• Oxygen• Dexamethasone• HB02• Comacare
c. Listthree(3)examinationfeaturesofapatientwithhighaltitudepulmonary
oedema.(3marks)• Tachycardia• Tachypnoea• Cyanosis• Crepitations
d. Listthree(3)managementstepsforapatientwithhighaltitudecerebral
oedema.(3marks)• Immediatedescent• Oxygen• Nifedipine• Maintainnormothermia
Question9(12marks)a. Listthree(3)cardinalfeaturesofapatientwithneurolepticmalignantsyndrome.(3
marks)• Neuromuscularrigidity• Alteredmentalstatus• Autonomicinstability
b. Listthree(3)riskfactorsforthedevelopmentofNeurolepticMalignantsyndrome.(3marks)
• Highdosesofneurolepticagent• Increaseddoseofneurolepticagentwithinthelast5/7• Largemagnitudedoseincrease• Parenteraladministration• Simultaneoususeof≥2neurolepticagents• Haloperidol• DepotFluphenazine• Youngage• Malesex• Psychiatriccomorbidity• Geneticfactors• Pre-existingorganicbraindisorders• Dehydration• HighCKlevelsduringepisodesofpsychosis(notassocwithNMS)• Otherpre-existingmedicaldisorders(trauma,infection,malnutrition,
premenstrual,thyrotoxicosis)
c. Listtwo(2)antidotesthatmaybebeneficialforapatientwithNeurolepticMalignantSyndrome.(2marks)
• Bromocriptine• Dantrolene• ECT
d. Otherthanantidoteuse,listfour(4)keycomponentstothemanagementofapatient
withNeurolepticMalignantsyndrome.(4marks)• RSIifsevererigiditycompromisingventilation/ortemp>38.5°C• Correcthypoglycaemia• Correcthyperthermia-NMparalysis• Avoidanyagentwithdopamineantagonisteffects• RxHTanTachycardia-Vasodilator(GTN/nitroprusside)• +/-Bz(mayplayaroleintheaetiologyofNMS-thereforespecificagents
preferred