医、技学院-华盛顿医疗手册培训急诊医学1

DepartmentofEmergencyMedicine,SAHZU,MedicalEmergencies,MaoZhang,MD,1.Airwayemergencies2.Heat-inducedinjury3.Overdoses,Overviews,1.Airwayemergencies,AcuteupperairwayobstructionPneumothoraxNear-drowning,Acuteupperairwayobstruction,1.Generalprincipals1.1Etiology.Inawakepatients-aforeignbody,angioedema.Inunconsciouspatientstongue,foreignbody,trauma,infection,angioedema,2.Diagnosis2.1Clinicalpresentation2.1.1Historycommonlyunavailable2.1.2PhysicalexaminationConsciouspatient:stridor,impairedphonation,sternalorsuprasternalretraction,chokingsign,repiratorydistressUnconsciouspatient:laboredbreathing,apnea,difficultventilation-Allpatientlookforurticaria,angioedema,fever,andevidenceoftrauma-partialobstructionintheawakepatientwithadequateventilation:lookingforairwayswelling,trismus,pharyngealobstruction,respiratoryretractions,stridor,neckmass.-airwayobstructioninanunconsciouspatientwithoutintactventilation:examinetheupperairwayvisuallyforevidenceofobstruction.,2.2Differentialdiagnosis-traumatothefaceandneck,foreignbody,infection,tumor,angioedema,laryngospasm.2.3Diagnostictesting2.3.1Imaging:partialobstructionintheawakepatientwithadequateventilation:-Radiographyoftheneck(PA,Lview):perofrmedinER-rapidCT:,2.4Diagnosticprocedurespartialobstructionintheawakepatientwithadequateventilation:-indirectlaryngoscopy-fiberopticnasopharyngolaryngoscopy,3.Treatment:preventCA3.1Nonsurgicalmanagement3.1.1Awakepatientwithoutventilation:-Heimlichmaneuver-asecondtechnique(backslaps,chestthrusts)3.1.2Unconsciouspatientwithoutventilation:-headtilt-chinliftmaneuverorajawthrust-oralornasalairway-ventilateBVM-laryngoscopetoremoveFB-thesupineHeimlichmaneuverorchestthrust,3.2Surgicalmanagement.Airwayobstructioninanunconsciouspatientwithoutintactventilation:-directlaryngoscopyandendotrachealintubation-asurgicalairway-cricothyrotomyusing12-14Gcatheterwithhigh-flowO2,1.Airwayemergencies,AcuteupperairwayobstructionPneumothoraxNear-drowning,Pneumothorax,1.Generalprincipals-primaryspontaneouspneumothorax-secondaryspontaneouspneumothorax-traumaticpneumothorax-latrogenicpneumothorax-Tensionpneumothorax:hypotension,respiratorydistress,2.Diagnosis2.1Clinicalpresentation2.1.1Historyacuteonsetofipsilateralchestorshoulderpainahistoryofrecentchesttraumaormedicalproceduredyspnea,2.1.2Physicalexaminationdecreasedbreathsounds,decreasedvocalfremitus,amoreresonantpercussionnote-tachypnea,respiratorydistress,largerandrelativelyimmobilehemithoraxseveredistress,diaphoresis,cyanosis,andhypotensionsubcutaneousemphysema,2.2Diagnostictesting2.2.1ECG-diminishedanteriorQRSamplitudeandananterioraxisshift,electromechanicaldissociation2.2.2Imagingchestradiograph:-aseparationofthepleuralshadowfromthechestwall-cautionformechanicallyventilatedpatients-mediastinalandtrachealshift,depressionofipsilateraldiaphragm,3.Treatment-dependsoncause,size,anddegreeofphysiologicderangement3.1Primarypneumothorax-resolvewithoutintervention(10dysfor15%)-discharge,-administerhigh-flowoxygen(small,mildlysymptomatic)-insertathoracostomytube(largerthan15%20%,symptomatic)-pleuralsclerosis,3.2Secondarypneumothorax-symptomaticandrequirelungreexpasion-thoracostomytubeandsuctionrequired-consultapulmonologist-surgeryforpersistentairleak,3.3Iatrogenicpneumothorax-managedconservatively,admitthepatient,administeroxygen,andrepeatthechestradiographin6hours-apneumothoraxcatheterwithaspirationoraone-wayvalve-managedwithachesttubeandsuction,3.4Tensionpneumothorax-decompresstheaffectedhemithoraximmediatelywitha14-gaugeneedleattachedtoafluid-filledsyringe-sealanychestwoundwithanocclusivedressing-arrangeforplacementofathoracostomytube,1.Airwayemergencies,AcuteupperairwayobstructionPneumothoraxNear-drowning,Near-drowning,1.Generalprincipals1.1Definition-definedasthesurvivalforatleast24hoursaftersubmersioninaliquidmedium-riskfactors:youth,inabilitytoswim,alcoholanddruguse,barotrauma,headandnecktrauma,epilepsy,syncope.-freshwaterdrowningandsaltwaterdrowning:-differences:pathophysiology-common:hypoxemiaandtissuehypoxia(relatedtoV/Qmismatch,acidosis,andhypoxicbraininjurywithcerebraledema),hypothermia,pneumonia,2.Diagnosis2.1Clinicalpresentation2.1.1Laboratories-serumelectrolytes,CBC,ABGs-obtainbloodalcohollevelanddrugscreenifthementalstatusisnotnormal2.1.2ECG-monitorthecardiacrhythmcontinuously,3.Treatment3.1Resuscitation-airwaymanagementandventilationwith100%oxygen-IVlinewith0.9%salineorlactatedRingersolution-immobilizethecervicalspine,astraumamaybepresent-treathypothermiavigorously,3.2Medication-reserveantibioticsfordocumentedinfection-prophylacticglucocorticoidshavenorole,4.Complications4.1Cerebraledema-occurssuddenlywithinthefirst24hoursandisamajorcauseofdeath-treatmentdoesnotappeartoincreasesurvival-nevertheless,ifoccurs,hyperventilatethepatienttoaPCO2notlowerthan25mmHgandadministermannitolorfurosemide-treatseizuresaggressivelywithphenytoin-Routineadministrationofglucocorticoids,hypothermiaorbarbituratecomaisnotrecommended-sedatethepatienttoreduceoxygenconsumption,4.2Pulmonarycomplications-administer100%oxygeninitially,titratingthereafterbyABGs-intubatethepatientendotracheallyandbeginmechanicalventilationwithPEEP-administerbronchodilatorsifbronchospasmispresent-Artificialsurfactantnotuseful,4.3Metaboliccomplications-managemetabolicacidosiswithmechanicalventilation,sodiumbicarbonate,andBPsupport,4.4Disposition-admitpatientswhohavesurvivedsevereepisodesofnear-drowningtoanICU-admitanypatientwithpulmonarysignsorsymptoms(cough,bronchospasm,abnormalABGsoroxygensaturation,orchestradiograph)-observetheasymptomaticpatientwithaquestionableorbriefwaterimmersionfor4-6hoursanddischargethepatientifthechestradiographandABGsarenormal,2.Heat-inducedinjury,HeatcrampHeatexhaustion.HeatsyncopeHeatstroke,Heatstroke,1.Generalprincipals1.1Classicheatstroke-coretemperatureshigherthan40.5-comatoseandanhidrotic-thoseatrisk:patientswhoarechronicallyill,dehydrated,elderly,orobese;thosewhoabusealcohol;andthosewhousesedatives,hypnotics,orantipsychotics.,1.2Exertionalheatstroke-occursinunacclimatizedindividualswhoexerciseinconditionsofhighambienttemperatureandhumidity-thoseatrisk:athletes,soldiers,andlaborers,particularlyiftheylacktowater-morelikelytohaveDIC,lacticacidosis,andrhabdomyolysis,2.Diagnosisbasedon-thehistoryofexposureorexercise-acoretemperatureusuallyof40.6orhigher-andchangesinmentalstatusrangingfromconfusiontodeliriumandcoma,2.1Differentialdiagnosis-malignanthyperthermia-anticholinergicpoisoning-Sympathomimetictoxicity-severehyperthyroidism-sepsis-meningitis-cerebralmalaria-encephalitis-hypothalamicdysfunctionduetohemorrhage-Brainabscess,2.2Diagnostictesting2.2.1laboratories-CBC-partialthromboplastintimeandprothrombintime-glucose-electrolytes-BUNandcreatinine-LDHandCK-ABGs-ECG,2.2.2ImagingifaCNSetiologyisconsideredlikely,-CTimaging-spinalfluidexamination,3.TreatmentImmediatecoolingisnecessary.-wrapthepatientinicedsheets-mistthepatientwithtepidwater(20-25)-coolthepatientwithalargeelectricfan-icepacksplacedatthegroin,axillae,andchest-gastriclavagewithicewater-discontinuecoolingmeasureswhenthecoretemperaturesreaches39,whichshouldbeachievedwithin30min,DantrolenesodiumnoteffectiveTreatseverehypertension,nitroprussidepreferableRelieveshiveringandvasoconstrictionMonitorcoretemperatureTreathypotension,avoidpurea-adrenergicagents,4.Complications-rhabdomyolysis:adequatevolumereplacement,manitolandbicarbonate-ARDS-seizures-hepaticinjury-congestiveheartfailure-coagulopathy,3.Overdoses,Overdose,General*Acetaminophen*Benzodiazepines*Ethanol*ColchicineNSAIDsOpioidsCCB.,Overdose,General,1.Generalprincipals1.1DefinitionAtoxidrome,ortoxicsyndrome,isaconstellationofclinicalexaminationfindingsthatassistsinthediagnosisandtreatmentofthepatientwhopresentswithanexposuretoanunknownagent.,1.2ClassificationThereare5generaltoxidromesthatencompassavarietyofxenobioticexposures.1.2.1Sympathomimetic-hypertension-tachycardia-pupillarydilatation-diaphoresis-drugs:cocaine,amphetamines,1.2.2Cholinergic-bradycardia-respiratorydepression,bronchoconstrictionandbronchorrhea,decreasedoxygensaturations-pinpointpupils,lacrimation,salivation-urination,defecation,gastrointestinaldistress,emesis-fasciculationsandparalysis-agents:organophosphateinsecticides,nervegases,1.2.3Anticholinergic-tachycardia-hyperthermia-mydriasis,dry,flushedskin,urinaryretention,decreasedintestinalmotility-CNS:agitation,delirium-agents:atropine,scopolamine,andantihistamines,1.2.4Opiate-respiratorydepression,oxygendesaturations-miosis-decreasedgastrointestinalmotility-coma1.2.5Sedativehypnotic-sedation,coma-rarelyrespiratorycompromise-agents:benzodiazepines,2.Diagnosis2.1Diagnostictesting2.1.1Laboratories-fingerstick-chemistry(bicarbonate,creatinine,.)-bloodgas(ABGsandVBGs)-serumdrugscreen:acetaminophen,salicylate,ethanol-urinedrugscreen:opioids,cocaine,amphetamines,cannabinoid,benzodiazepine,pcp,2.1.2ECG-TheimportantcardiactoxinstendtoprolongthePRinterval,theQRS,ortheQTinterval2.1.3Imaging-Ingeneral,thereisalimitedroleofdiagnosticimagingintoxicology-Themostusefulimagingstudyinoverdosesistheabdominalradiograph,3.TreatmentItiscrucialtomaintaintheairway,checkforadequacyofbreathingandcirculation,andcheckafingerstickbloodglucoseinthepatientwithcoma.3.1Preventionofabsorption-gastricemptyingbyinducingemesisorlavage-activatedcharcoal(AC):1g/kgBW-whole-bowelirrigation-cathartics:havenorole,3.2Enhancedelimination-forceddiuresis-urinaryalkalinizationorurinaryacidification-hemodialysisandhemoperfusion3.3AntidotesItwillbediscussedunderspecifictoxicities.3.4DispositionReceiveapsychiatricevaluationpriortodischargeforcertainpts,4.Overdoses,Overdose,General*Acetaminophen(APAP)*Benzodiazepines*Ethanol*ColchicineNSAIDsOpioidsCCB.,Acetaminophen,1.Generalprincipals-ananalgesic,namelyAPAP,Tylenol,orParacetamol-oftenusedincoldandfluremedies,thetreatmentoffevers,headaches,andacuteandchronicpain-oftensoldincombinationpreparationstogetherwithNSAIDs,opiateanalgesics,orsedatives-therecommendedmaximumdoseforadults:4g/d,1.1Epidemiology-theleadingcauseoftoxicologicfatalitiesintheUS-APAP-inducedhepatotoxicityisthemostfrequentcauseofacuteliverfailureintheUS1.2EtiologyUnintentionaloverdosingismuchmorecommonthanintentionalingestioninsuicideattempts,especiallyinelderlypatientsonchronicpain.,1.3Pathophysiology-Absorption:-APAPserumlevelspeak30-60minafteroralingestion;-Absorptionisoftendelayedinoverdoseandpeaklevelsareusuallyreachedafter2-8h.-Overdose:-Thehepaticconjugationpathwaysbecomesaturatedinoverdose;-Acascadeofbiochemicalchangesoccursintheliverandcentrilobularcellnecrosisresults.,1.4Riskfactors-decreasedglutathionestores(fasting,malnutrition,anorexianervosa,chronicalcoholism,febrileillness,chronicdisease)-P450enzymeinducers(ethanol,INH,phenytionandotheranticonvulsants,barbiturates,smoking),2.Diagnosis2.1Clinicalpresentation2.1.1First24hoursasymptomatic2.1.224-48hourshepatotoxicstage:-RUQtenderness-transaminitis,bilirubinemia,andelevatedPT/INR,2.1.32-4daysfulminanthepaticfailurestage:-hepaticenzymeelevationalongwithjaundice-coagulopathywithhighriskofspontaneousbleeding-hypoglycemia-anuria-cerebraledema2.1.44-14daysrecoverystage,2.2History-areliabletimeofingestion-theamount,form(combinationpreparationsorextended-releaseform),periodoftime-inquireaboutothercoingestants(alcohol,otherdrugs,othermedications)2.3PhysicalexaminationAssessairway,breathing,andcirculationsandmentalstatus.,2.4Diagnosticcriteria-150mg/kgisthepotentiallytoxiclimitthatrequirestherapeuticintervention.-ObtainanAPAPserumlevelat4horlaterafteringestion-PlottheAPAPconcentrationontheRumack-Matthewnomogramtoassessthepossibilityofhepatictoxicity.-prognosticmarkerstopredicttheprobabilityofprogressiveliverfailure:-PH100,creatinine3.3mmol/L,severehepaticencephalopathy(3-4)-serumphosphate1.2mmol/Londays2-4(additionalcriterion)-arterialserumlactate3.0mmol/Lafterfluidresuscitation(additionalcriterion),2.5Diagnostictesting-APAPserumlevelat4h-LFT-AST-PT/INR,serumbicarbonate,bloodPH,serumlactate,renalfunctionpanel,andserumphosphatelevel,3.TreatmentGastriclavageisnotuseful3.1Activatedcharcoal-patientswithisolatedAPAPexposurewhopresentlessthan4hafteringestion,1g/kgBW,3.2NAC(N-acetylcysteine)-aspecificantidotetopreventAPAP-relatedhepatotoxicity-Itshouldbeadministeredwithin8hafteringestion-IVadministrationispreferred-IVdosing:-firstIh,150mg/kg-thereafter,14mg/kg/hrfor20hours-Patientswithtoxicliverfailureshouldbetransferredtoatransplantcenterasearlyaspossible.,-NACindications:-patientafteracutepoisoningwithatoxicAPAPlevelaccordingtothenomogram-patientswhopresentbeyond8hafteracuteingestion-patientswhopresentmorethan24hafteracuteingestionandstillhaveadetectableserumAPAPlevelorelevatedAST-patientswithchronicAPAPexposurewhopresentwithelevatedtransaminases-patientswithsignsoffulminanthepaticfailure,4.Complications-hyperglycemia-electrolyteimbalances-GIbleeding-acid-basedisturbances-cerebraledema-infections-renalfailure,4.Overdoses,Overdose,General*Acetaminophen*Benzodiazepines*Ethanol*ColchicineNSAIDsOpioidsCCB.,Benzodiazepines,1.Generalprincipals-Benzodiazepineshaveawidesafetymargin-Deathsareusuallyrelatedtothepresenceofacoingestantorethanol,2.Diagnosis2.1Clinicalpresentation2.1.1History-difficulttoelicitaspatients