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:tomre@barwonhealth.org.au 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