医、技学院-华盛顿医疗手册培训(急诊医学1)

DepartmentofEmergencyMedicine,

SAHZU

MedicalEmergenciesMaoZhang,MD

1.Airwayemergencies2.Heat-inducedinjury3.Overdoses

Overviews

1.Airwayemergencies

√

Acuteupperairwayobstruction

Pneumothorax

Near-drowningAcuteupperairwayobstruction

1.Generalprincipals

1.1Etiology.Inawakepatients-aforeignbody,angioedema

.Inunconsciouspatients–tongue,foreignbody,trauma,infection,angioedema2.Diagnosis

2.1Clinicalpresentation2.1.1History–commonlyunavailable

2.1.2Physicalexamination

Consciouspatient:stridor,impairedphonation,sternalorsuprasternalretraction,chokingsign,repiratorydistress

Unconsciouspatient:laboredbreathing,apnea,difficultventilation

-

Allpatient

lookforurticaria,angioedema,fever,andevidenceoftrauma-

partialobstructionintheawakepatientwithadequateventilation:

lookingforairwayswelling,trismus,pharyngealobstruction,respiratoryretractions,stridor,neckmass....

-airwayobstructioninanunconsciouspatientwithoutintactventilation:examinetheupperairwayvisuallyforevidenceofobstruction.2.2Differentialdiagnosis

-traumatothefaceandneck,foreignbody,infection,tumor,angioedema,laryngospasm….

2.3Diagnostictesting

2.3.1Imaging:

partialobstructionintheawakepatientwithadequateventilation:

-

Radiographyoftheneck(PA,Lview):perofrmedinER

-rapidCT:

2.4Diagnosticprocedures

partialobstructionintheawakepatientwithadequateventilation:

-

indirectlaryngoscopy

-fiberopticnasopharyngolaryngoscopy

3.Treatment:preventCA

3.1Nonsurgicalmanagement

3.1.1

Awakepatientwithoutventilation:

-

Heimlichmaneuver

-

asecondtechnique(backslaps,chestthrusts)

3.1.2

Unconsciouspatientwithoutventilation:-

headtilt-chinliftmaneuverorajawthrust

-

oralornasalairway

-

ventilateBVM

-

laryngoscopetoremoveFB-

thesupineHeimlichmaneuverorchestthrust3.2Surgicalmanagement

.Airwayobstructioninanunconsciouspatientwithoutintactventilation:-directlaryngoscopyandendotrachealintubation-asurgicalairway-cricothyrotomyusing12-14Gcatheterwithhigh-flowO2

1.Airwayemergencies

Acuteupperairwayobstruction√

Pneumothorax

Near-drowningPneumothorax1.Generalprincipals

-primaryspontaneouspneumothorax-secondaryspontaneouspneumothorax

-traumaticpneumothorax

-latrogenicpneumothorax

-Tensionpneumothorax:hypotension,respiratorydistress2.Diagnosis

2.1Clinicalpresentation

2.1.1History

–acuteonsetofipsilateralchestorshoulderpain–ahistoryofrecentchesttraumaormedicalprocedure

–dyspnea

2.1.2Physicalexamination

–decreasedbreathsounds,decreasedvocalfremitus,amoreresonantpercussionnote

-tachypnea,respiratorydistress,largerandrelativelyimmobilehemithorax

–severedistress,diaphoresis,cyanosis,andhypotension

–subcutaneousemphysema2.2Diagnostictesting

2.2.1

ECG

-

diminishedanteriorQRSamplitudeandananterioraxisshift,electromechanicaldissociation

2.2.2Imaging

chestradiograph:

-

aseparationofthepleuralshadowfromthechestwall

-cautionformechanicallyventilatedpatients

-mediastinalandtrachealshift,depressionofipsilateraldiaphragm3.Treatment

-dependsoncause,size,anddegreeofphysiologicderangement

3.1Primarypneumothorax

-

resolvewithoutintervention(10dysfor~15%)

-discharge,-

administerhigh-flowoxygen(small,mildlysymptomatic)-

insertathoracostomytube(largerthan15%~20%,symptomatic)-pleuralsclerosis3.2Secondarypneumothorax

-symptomaticandrequirelungreexpasion

-thoracostomytubeandsuctionrequired

-consultapulmonologist

-surgeryforpersistentairleak3.3Iatrogenicpneumothorax-managedconservatively,admitthepatient,administeroxygen,andrepeatthechestradiographin6hours-apneumothoraxcatheterwithaspirationoraone-wayvalve

-managedwithachesttubeandsuction3.4Tensionpneumothorax

-decompresstheaffectedhemithoraximmediatelywitha14-gaugeneedleattachedtoafluid-filledsyringe-sealanychestwoundwithanocclusivedressing

-arrangeforplacementofathoracostomytube1.Airwayemergencies

Acuteupperairwayobstruction

Pneumothorax√

Near-drowningNear-drowning

1.Generalprincipals

1.1Definition-definedasthesurvivalforatleast24hoursaftersubmersioninaliquidmedium-riskfactors:youth,inabilitytoswim,alcoholanddruguse,barotrauma,headandnecktrauma,epilepsy,syncope....

-freshwater

drowningandsaltwaterdrowning:

-differences:pathophysiology

-common:hypoxemiaandtissuehypoxia(relatedto[V/Q]mismatch,acidosis,andhypoxicbraininjurywithcerebraledema),hypothermia,pneumonia2.Diagnosis

2.1Clinicalpresentation

2.1.1Laboratories

-serumelectrolytes,CBC,ABGs

-

obtainbloodalcohollevelanddrugscreenifthementalstatusisnotnormal

2.1.2ECG

-

monitorthecardiacrhythmcontinuously3.Treatment

3.1Resuscitation

-

airwaymanagementandventilationwith100%oxygen-

IVlinewith0.9%salineorlactatedRingersolution-

immobilizethecervicalspine,astraumamaybepresent-

treathypothermiavigorously3.2Medication

-

reserveantibioticsfordocumentedinfection

-

prophylacticglucocorticoidshavenorole4.Complications

4.1Cerebraledema-

occurssuddenlywithinthefirst24hoursandisamajorcauseofdeath-

treatmentdoesnotappeartoincreasesurvival-

nevertheless,ifoccurs,hyperventilatethepatienttoaPCO2notlowerthan25mmHgandadministermannitolorfurosemide-

treatseizuresaggressivelywithphenytoin

-

Routineadministrationofglucocorticoids,hypothermiaorbarbituratecomaisnotrecommended-

sedatethepatienttoreduceoxygenconsumption4.2Pulmonarycomplications

-administer

100%oxygeninitially,titratingthereafterbyABGs-intubatethepatientendotracheallyandbeginmechanicalventilationwithPEEP-administerbronchodilatorsifbronchospasmispresent

-Artificialsurfactantnotuseful

4.3Metaboliccomplications

-managemetabolicacidosiswithmechanicalventilation,sodiumbicarbonate,andBPsupport4.4Disposition

-admitpatientswhohavesurvivedsevereepisodesofnear-drowningtoanICU-admitanypatientwithpulmonarysignsorsymptoms(cough,bronchospasm,abnormalABGsoroxygensaturation,orchestradiograph)-observetheasymptomaticpatientwithaquestionableorbriefwaterimmersionfor4-6hoursanddischargethepatientifthechestradiographandABGsarenormal2.Heat-inducedinjury

Heatcramp

Heatexhaustion

.Heatsyncope√

HeatstrokeHeatstroke1.Generalprincipals

1.1Classicheatstroke

-coretemperatureshigherthan40.5℃

-comatoseandanhidrotic-thoseatrisk:patientswhoarechronicallyill,dehydrated,elderly,orobese;thosewhoabusealcohol;andthosewhousesedatives,hypnotics,orantipsychotics.1.2Exertionalheatstroke

-occursinunacclimatizedindividualswhoexerciseinconditionsofhighambienttemperatureandhumidity

-thoseatrisk:athletes,soldiers,andlaborers,particularlyiftheylacktowater-morelikelytohaveDIC,lacticacidosis,andrhabdomyolysis2.Diagnosis

basedon-thehistoryofexposureorexercise-acoretemperatureusuallyof40.6℃orhigher-andchangesinmentalstatusrangingfromconfusiontodeliriumandcoma

2.1Differentialdiagnosis

-malignanthyperthermia

-anticholinergicpoisoning

-Sympathomimetictoxicity

-severehyperthyroidism

-sepsis

-meningitis

-cerebralmalaria

-encephalitis

-hypothalamicdysfunctionduetohemorrhage

-Brainabscess

2.2Diagnostictesting

2.2.1laboratories

-CBC-partialthromboplastintimeandprothrombintime-glucose-electrolytes-BUNandcreatinine-LDHandCK-ABGs-ECG2.2.2Imaging

ifaCNSetiologyisconsideredlikely,

-CTimaging-spinalfluidexamination3.Treatment

Immediatecoolingisnecessary.-wrapthepatientinicedsheets-mistthepatientwithtepidwater(20-25℃

)-coolthepatientwithalargeelectricfan-icepacksplacedatthegroin,axillae,andchest-gastriclavagewithicewater-discontinuecoolingmeasureswhenthecoretemperaturesreaches39℃,whichshouldbeachievedwithin30minDantrolenesodiumnoteffectiveTreatseverehypertension,nitroprussidepreferableRelieveshiveringandvasoconstrictionMonitorcoretemperatureTreathypotension,avoidpurea-adrenergicagents4.Complications

-rhabdomyolysis:adequatevolumereplacement,manitolandbicarbonate-ARDS-seizures-hepaticinjury-congestiveheartfailure-coagulopathy

3.Overdoses√Overdose,General*

Acetaminophen*

Benzodiazepines*

Ethanol*

ColchicineNSAIDsOpioidsCCB….Overdose,General1.Generalprincipals

1.1Definition

Atoxidrome,ortoxicsyndrome,isaconstellationofclinicalexaminationfindingsthatassistsinthediagnosisandtreatmentofthepatientwhopresentswithanexposuretoanunknownagent.1.2Classification

Thereare5generaltoxidromesthatencompassavarietyofxenobioticexposures.

1.2.1Sympathomimetic

-hypertension-tachycardia-pupillarydilatation-diaphoresis-drugs:cocaine,amphetamines1.2.2Cholinergic

-bradycardia-respiratorydepression,bronchoconstrictionandbronchorrhea,decreasedoxygensaturations-pinpointpupils,lacrimation,salivation-urination,defecation,gastrointestinaldistress,emesis-fasciculationsandparalysis-agents:organophosphateinsecticides,nervegases1.2.3Anticholinergic

-tachycardia-hyperthermia-mydriasis,dry,flushedskin,urinaryretention,decreasedintestinalmotility-CNS:agitation,delirium-agents:atropine,scopolamine,andantihistamines1.2.4Opiate

-respiratorydepression,oxygendesaturations-miosis-decreasedgastrointestinalmotility-coma1.2.5Sedativehypnotic

-sedation,coma-rarelyrespiratorycompromise-agents:benzodiazepines2.Diagnosis

2.1Diagnostictesting

2.1.1Laboratories

-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-Themostusefulimagingstudyinoverdosesistheabdominalradiograph3.Treatment

Itiscrucialtomaintaintheairway,checkforadequacyofbreathingandcirculation,andcheckafingerstickbloodglucoseinthepatientwithcoma.3.1Preventionofabsorption

-gastricemptyingbyinducingemesisorlavage-activatedcharcoal(AC):1g/kgBW-whole-bowelirrigation-cathartics:havenorole3.2Enhancedelimination

-forceddiuresis-urinaryalkalinizationorurinaryacidification-hemodialysisandhemoperfusion3.3Antidotes

Itwillbediscussedunderspecifictoxicities.3.4

DispositionReceiveapsychiatricevaluationpriortodischargeforcertainpts4.Overdoses

Overdose,General*√Acetaminophen(APAP)*Benzodiazepine