Hypothermia-PhiladelphiaUniversity：低温-课件

1、HYPOTHERMIAAlcohol Related IllnessHypothermia - AlcoholHypothermiaEpidemiologyPhysiology of Temperature ControlEtiology of HypothermiaPathophysiology/TreatmentHypothermia and TraumaAlcoholEthanol IntoxicationPathophysiology/TreatmentAlcohol AbuseHypothermiaEpidemiologyDefined as temp 35O C (700 die

2、each year in US from hypothermia of those are 65+ years oldIndividuals at age extremes and those with AMS are at greatest riskPhysiology of Temperature ControlConductionTransfer of heat by direct contact down temperature gradient.ConvectionTransfer of heat by movement of heated material. (i.e. wind)

3、RadiationLoss of heat from non-insulated areasH2O EvaporationLoss of heat through exhalationTemperature HomeostasisOpposition of Heat LossHypothalamusStimulation of sympathetic nervous system if temp below set pointBehavioral responsesWearing clothes when its coldLeaving cold environmentHeat GainShi

4、vering“Non-shivering thermogenesis”Etiology of HypothermiaAccidentalImmersion and non-immersion cold exposureMetabolicHypoendocrine states (hypothyroid, hypoadrenalism, hypopituitarism)HypoglycemiaHead traumaTumorEtiology of Hypothermia (cont.)Wernickes disease.Drug inducedAlcohol (majority of hypot

5、hermic pts in US are intoxicated)SedativesPhenothiazinesInsulinSepsisEtiology of Hypothermia (cont.)Severe dermal diseaseBurnsExfoliative dermatitisAcute incapacitating illnessSevere infectionsDKAPsychotic disordersOther conditions causing impaired thermoregulatory functionResuscitation with room te

6、mperature fluidPathophysiologyMild Hypothermia 34-36 C (93.2-96.8 F)ExcitationPhysiologic adjustments to retain heatModerate Hypothermia 32-34 C (89.6-93.2 F)AdynamicMetabolism slowsDecreased O2 demandDecreased CO2 productionSevere Hypothermia 32 9 (89.6 F)Shivering ceasesPathophysiology (cont.)Exci

7、tationSympathetic response (HR, BP, and Cardiac Output all rise).AdynamicHR, CO, BP decrease due to negative ino/chrono tropic effects of hypothermiaPathophysiology (cont.)Hypothermic EKG changesOsborne or J wavesT-wave inversionProlonged PR, QRS, QT intervalsArrhythmias may include bradycardia, slo

8、w AF, VF, or asystoleExample26C28C28.5C29.5CabcdPathophysiology (cont.)Pathophysiology (cont.)Systemic Effects of Progressing HypothermiaPulmonary:Tachypnea RR & TV Bronchorrhea, gag/cough reflexCNSDiscoordination confusion lethargy comaFurther deterioration may be cerebro-protectiveRenal“Cold Diure

9、sis” due to renal hypoperfusion3rd spacing hemoconcentration embolic complications rhabdomyolysis, etc.CoagulopathyTreatmentStop further heat lossBegin warming processPassive external warmingActive external warmingActive internal rewarmingWarmed oxygen and IV fluidsTreatment (cont.)Maintain horizont

10、al position Vertical position may compromise cerebral and systemic perfusionAvoid rough movements and activitiesHandle victim gently during CPR, intubation, BVM ventilation, vascular accessTreatment (cont.)Cardiac ArrestIf VF present:Defibrillate x 3 prnETT w/ warmed, humidified O2Warmed IV fluids (

11、avoid overhydration)If temp 30 CCPRDefib prn as core temp risesIV meds as indicated (longer than normal intervals)Continue rewarming during transportOther Treatment ConsiderationsAMSNarcan 2mg IVThiamine 100mg IVD50/W 25gm IV if BGLTreatment (cont.)Passive RewarmingRemoval from environmentInsulation

12、Active Core Rewarming Inhalation rewarming Heated IV fluids GI tract lavage Bladder lavage Peritoneal lavage Pleural lavage Extracorporeal rewarming Mediastinal lavageActive External Rewarming Warm H2O Immersion Heating blankets Heated objects Radiant Heat Forced airRewarming Caution After-drop Phen

13、omenon Temperature drop and acidosis provoke serious arrhythmiasCold acidotic blood causes drop in core tempCold blood from dilated peripheral vessels carries high lactic acid levels to core vessels Peripheral vasodilation (BP drops)Initial active external rewarming leads to Hypothermia Trauma Pt.Th

14、ree mechanisms that contribute tohypothermia-induced coagulopathy intrauma include:1.Platelet Dysfunction2.Enhanced Fibrinolytic Activity3.Alteration In Enzyme FunctionsHypothermia Trauma Pt.Platelet DysfunctionInhibition of Thromboxane B2 production causes the normal response of platelet aggregatio

15、n to decrease. The plateletsare therefore stored in the spleen and liver, and left unavailable for use.Hypothermia Trauma Pt.Enhanced Fibrinolytic ActivityTrauma-induced hypothermia causes a heparin-like substance to be released, thus causing a disseminated intravascular clotting (DIC)-like syndrome

16、.This is marked by an increase in prothrombin (PT) and partial thromboplastin times (PTT), and an increase in fibrin split products.Hypothermia Trauma Pt.Alteration In Enzyme FunctionsHageman factor and Thromboplastin are needed to form clots at the site of injured endothelium.Hypothermia alters the

17、 function of these enzymes and others, therefore increasingbleeding and clotting times.Hypothermia Trauma Pt.Coagulopathy PerpetuatedBlood transfusions/fluid resuscitation may lead to or exacerbate hypothermia.Silbergleit et al report that room (or ambient)temperature IV fluids, used in resuscitatio

18、n,increase hypothermia or may actually causesecondary hypothermia in trauma patients.Crystalloids dilute the availability of coagulationfactorsBanked blood is low in platelets and clottingfactors, especially Factors V and VIIIHypothermia Near DrowningCerebral ProtectionProtective Hypothermia (H2O 5

19、C) core body temp 28 CWater must be icy.Heat loss must occur rapidly to metabolic rate before significant hypoxemia begins.Very unlikely for this to happenMore commonly, hypothermic near drowning have higher mortality rate.IntermissionAcute Ethanol IntoxicationEthanolMost frequently used and abused

20、intoxicant of adult Americans will consume at least one drink per year36% will smoke a fagBeer is number 4 on the most consumed beverage list (pop, milk, coffee)Average American pounded 2 gallons of pure ethanol 1997Down from 2.77 in 1981EthanolDistilled spirits40-50% (80-100 proof)Some as high as 7

21、5%Wine10-20%Beer 2-6%Other StuffMouthwash (up to 75%)Cologne (40-60%)Medicinal preparations (as high as 65%)Pathophysiology - EthanolCNS depressantStimulant effect may occur concentrationAbsorbed mainly in small bowelAlso occurs in mouth, esophagus, stomach, and large bowelMajority metabolized by li

22、verSmall % excreted by lungs, in urine, or sweatPathophysiology - EthanolAlcohol and WomenMore prone to alcohol related health problemsSmaller volume of distributionNo first pass metabolism capabilityAlcohol dehydrogenaseAlcohol and PregnancyLow birth weight infantsFetal alcohol syndromeFacial dysmo

23、rphology Mental/growth retardationEthanol IntoxicationSigns and SymptomsDisinhibited behaviorCNS depressionNystagmusSlurred speech motor coordination/controlEthanol IntoxicationSigns and Symptoms (cont.) BP hypotensionDue to PVR and/or volume lossTachycardiaRespiratory depressionUsually in unhabitua

24、ted usersMorbidity/MortalityUsually due to impaired judgment sequelaeTreatmentSupportiveABCsPrepare to support respirationsAltered Mental Status25 gm D50/W prnNarcan 2 mgThiamine 100 mgEffects of Alcohol AbuseTrauma and Alcohol4th highest cause of death, after coronary disease, cerebro-vascular acci

25、dents and cancer. Main cause of death before the age of 40 years. 40-50% of traffic deaths25-35% of non fatal car accidents64% of fires and burns48% of cases of hypothermia and freezing20% of suicidesImplicated in 40% of falls and 50 % of murders (victims or criminals). Effects of Alcohol AbuseCNSAc

26、ute IntoxicationAlcohol withdrawalSeizuresHallucinationsWernickes encephalopathyKorsakoffs psychosisDementiaDepression/antisocial/suicidalEffects of Alcohol AbuseGastrointestinalEsophageal varicesErosive gastritisHepatitis/liver failurePeptic ulcer diseasePancreatitisOropharyngeal, esophageal, gastr

27、ic, hepatic and pancreatic malignanciesEffects of Alcohol AbuseCardiovascularHypertensionCardiomyopathyStrokeDysrhythmic events (intoxication or withdrawal)Endocrine/MetabolicTesticular atrophyAlcoholic ketoacidosisFolic acid and thiamine deficienciesEffects of Alcohol AbuseChallenges of Evaluation and TreatmentObtaining reliable historyObtaining cooperative care and evaluationDifficult to reaso