PVSSPVSS ConferenceConference

Hypothermia,Hypothermia, DrowningDrowning andand ColdCold--WaterWater SurvivalSurvival

By

RADM Alan M. Steinman USPHS / USCG (Ret) DisastersDisasters atat SeaSea AircraftAircraft DitchingDitching atat SeaSea FallingFalling OverboardOverboard WashedWashed OverboardOverboard Understand Cold Exposure: Immersion vs Submersion

Immersion - Head Out! Submersion = Head In !! PhysiologicalPhysiological ResponsesResponses toto SuddenSudden ImmersionImmersion inin ColdCold WaterWater Responses to Cold Water Immersion

• Cold Shock (0-2 min) • Functional Disability (2-15 min) • Hypothermia (> 15-30 min) • Peri-Rescue Collapse ColdCold--ShockShock ResponseResponse

„ OccursOccurs immediatelyimmediately uponupon entryentry

„ LastsLasts upup toto 22 minutesminutes

„ CausedCaused byby stimulationstimulation ofof truncaltruncal skinskin nervenerve endingsendings

„ TheThe coldercolder thethe water,water, thethe strongerstronger thethe responseresponse ColdCold--ShockShock ResponseResponse

„ GaspGasp reflexreflex

„ HyperventilationHyperventilation

„ DifficultyDifficulty holdingholding youryour breathbreath

„ TachycardiaTachycardia (rapid(rapid heartheart rate)rate)

„ HypertensionHypertension (elevated(elevated bloodblood pressure)pressure) When and How You Can Die in Cold Water

1) Cold Shock Response (0-2 minutes)

Gasp Æ Drown (Keep head out of water)

Hyperventilation Faint Æ (Don’t panic, keep calm) Æ Drown

à Cardiac Work Æ Cardiac Arrest (If existing heart problems) IncapacitationIncapacitation inin ColdCold WaterWater

„ DifficultyDifficulty swimmingswimming

„ LossLoss ofof functionalfunctional abilityability

„ IncreasedIncreased viscosityviscosity ofof coldcold waterwater

„ LossLoss ofof manualmanual dexteritydexterity

„ MuscleMuscle crampingcramping

„ SwimmingSwimming speedsspeeds onsetonset ofof hypothermiahypothermia When and How You Can Die in Cold Water Local Cooling Decreases Performance Or Functional Disability (2-15 minutes)

• If you can’t get out in 5-15 minutes, you might not get out on your own power!

• If so, prepare to survive.

• Widen window of opportunity for rescue.

• Thrashing around will - increase heat loss - cause exhaustion (Drowning) When and How You Can Die in Cold Water

Onset of Hypothermia (>30 minutes on)

• Cooling to UNCONSCIOUSNESS • If head goes under, Drowning (30-120 minutes).

• If head above water… • Cooling to CARDIAC ARREST, Death (90-180 minutes or more, depending on water temp, body size, etc.) SummarySummary ofof ColdCold WaterWater RisksRisks

„ ColdCold ShockShock (0(0--22 minutes)minutes)

„ FunctionalFunctional disabilitydisability (2(2--3030 minutes)minutes)

„ HypothermiaHypothermia (>30(>30 minutes)minutes) RoleRole ofof FlotationFlotation

„ PFDs,PFDs, immersionimmersion suits,suits, etc.etc. cancan assistassist inin survivingsurviving coldcold--shockshock && swimswim failurefailure

„ RoughRough seasseas remainremain aa significantsignificant risk,risk, eveneven withwith flotationflotation assistanceassistance

„ ImmersionImmersion suitssuits cancan assistassist inin preventionprevention ofof hypothermia,hypothermia, ifif properlyproperly donneddonned HypothermiaHypothermia inin ColdCold WaterWater AirAir isis anan ExcellentExcellent InsulatorInsulator Body Fat is an Excellent Insulator HeatHeat isis lostlost fromfrom thethe bodybody inin proportionproportion toto itsits surfacesurface areaarea

Large,Large, fatfat peoplepeople coolcool farfar moremore slowlyslowly thanthan dodo small,small, thinthin oror lankylanky peoplepeople

AdultsAdults coolcool moremore slowlyslowly thanthan dodo childrenchildren HypothermiaHypothermia resultsresults whenwhen moremore heatheat isis lostlost fromfrom thethe bodybody thanthan isis producedproduced (through(through metabolismmetabolism andand shivering)shivering) andand retainedretained (through(through bodybody--fat,fat, clothing,clothing, andand behavioralbehavioral adaptation).adaptation). WaterWater isis anan ExcellentExcellent ConductorConductor ofof HeatHeat PhysiologyPhysiology ofof HypothermiaHypothermia

„„HypothermiaHypothermia defineddefined asas corecore temptemp << 9595 degdeg F.F. „„EveryEvery organorgan systemsystem isis affectedaffected (e.g.,(e.g., similarsimilar toto multiplemultiple trauma)trauma) PhysiologyPhysiology ofof HypothermiaHypothermia

„„ ConstrictionConstriction ofof surfacesurface bloodblood vesselsvessels „„ ColdCold sensationsensation andand shiveringshivering „„ PhysicalPhysical impairmentsimpairments (motor(motor skills)skills) „„ MentalMental impairmentimpairment „„ ColdCold--inducedinduced urinationurination PhysiologyPhysiology ofof HypothermiaHypothermia

„„ AbnormalAbnormal heartheart beatsbeats andand slowingslowing ofof thethe heartheart raterate „„ DecliningDeclining bloodblood pressurepressure „„ DecreasedDecreased metabolismmetabolism „„ CessationCessation ofof shiveringshivering „„ LossLoss ofof consciousnessconsciousness „„ VentricularVentricular fibrillationfibrillation // CardiacCardiac arrestarrest ClassificationClassification ofof HypothermiaHypothermia

„„ 3535--3737 degdeg C:C: coldcold--sensation,sensation, shivering,shivering, constrictionconstriction ofof surfacesurface bloodblood vesselsvessels

„„ 3232--3535 degdeg C:C: MildMild hypothermiahypothermia;; physicalphysical andand mentalmental impairmentsimpairments ClassificationClassification ofof HypothermiaHypothermia

„„ 2828--3232 degdeg C:C: ModerateModerate hypothermiahypothermia;; cessationcessation ofof shivering,shivering, abnormalabnormal heartheart beats,beats, lossloss ofof consciousnessconsciousness

„„ <28<28 degdeg C:C: SevereSevere hypothermiahypothermia;; vitalvital signssigns reducedreduced oror absent;absent; spontaneousspontaneous ventricularventricular fibrillationfibrillation oror cardiaccardiac arrestarrest BloodBlood VesselVessel ConstrictionConstriction onon ImmersionImmersion inin ColdCold WaterWater HHiigghh HHeeaatt LLoossss AArreeaass iinn HHyyppootthheerrmmiiaa DoDo NOTNOT DrownproofDrownproof HELPHELP PositionPosition HuddleHuddle TechniqueTechnique ShouldShould youyou SwimSwim forfor Shore?Shore? HHeeaatt LLoossss AArreeaass AAfftteerr SSwwiimmmmiinngg iinn CCoolldd WWaatteerr

PhysiologyPhysiology ofof DrowningDrowning

„„ LossLoss ofof breathbreath--holdingholding abilityability „„ AspirationAspiration ofof waterwater „„ Coughing,Coughing, violentviolent strugglestruggle toto reachreach surfacesurface „„ LaryngospasmLaryngospasm (vocal(vocal cordcord constriction)constriction) PhysiologyPhysiology ofof DrowningDrowning

„„ LowLow levelslevels ofof oxygenoxygen „„ LossLoss ofof consciousnessconsciousness „„ ReflexReflex swallowingswallowing „„ VentricularVentricular fibrillationfibrillation „„ DeathDeath PathophysiologyPathophysiology ofof DrowningDrowning

„„ SubmersionSubmersion inin coldcold--waterwater isis associatedassociated withwith aa significantlysignificantly higherhigher survivalsurvival raterate „„ RapidRapid coolingcooling ofof thethe brainbrain increasesincreases thethe abilityability toto survivesurvive lowlow oxygenoxygen levelslevels „„ HigherHigher probabilityprobability ofof successfulsuccessful resuscitationresuscitation „„ EvenEven upup toto 6060 minutesminutes submersion!submersion! PracticalPractical ApplicationsApplications ofof StudiesStudies inin ColdCold--WaterWater ImmersionImmersion HypothermiaHypothermia TestTest SubjectsSubjects

RoughRough WaterWater vs.vs. CalmCalm WaterWater TestTest GarmentsGarments

„ FSFS FlightFlight SuitSuit (control)(control) „ BCBC BoatBoat CrewCrew CoverallCoverall (Stearns(Stearns worksuitworksuit)) „ ACAC AircrewAircrew CoverallCoverall (Mustang(Mustang worksuitworksuit)) „ WSWS FullFull WetWet SuitSuit „ SWSSWS ShortShort WetWet SuitSuit „ FCFC FloatFloat CoatCoat „ ISIS ImmersionImmersion SuitSuit „ DSDS DryDry SuitSuit (working(working deckdeck suit)suit) TestTest ConditionsConditions

„ 5050 degreedegree F.F. waterwater

„ CalmCalm SeasSeas –– testtest performedperformed atat docksidedockside

„ RoughRough SeasSeas –– 44--66 ftft waveswaves everyevery 3030 secssecs;; CalmCalm WaterWater TestTest –– 5050 deg.deg. F.F. RoughRough WaterWater TestTest –– 5050 deg.deg. F.F. CalmCalm vs.vs. RoughRough WaterWater ResultsResults

Cooling Rates in degrees C. per hour

4 3.5 3 2.5 2 Calm 1.5 Rough 1 0.5 0 FS FC SWS AC BC WS DS IS SurvivorSurvivor LocationLocation inin ColdCold Water:Water: TestTest ConditionsConditions

„ RoughRough SeasSeas -- 55 footfoot breakingbreaking waveswaves „ 4343 deg.deg. F.F. waterwater 4646 deg.deg. F.F. airair 1515 knotknot windwind „ CapsizedCapsized boatboat „ SurvivorsSurvivors inin thethe waterwater nextnext toto thethe boatboat „ SurvivorsSurvivors atopatop thethe boatboat exposedexposed toto windwind andand waveswaves „ SurvivorsSurvivors inin aa oneone--personperson liferaftliferaft WhatWhat wouldwould youyou do?do?

GetGet outout ofof thethe water,water, sitsit atopatop thethe boat,boat, andand thusthus bebe exposedexposed toto windwind--chillchill andand waves;waves;

OROR

StayStay inin thethe water,water, hanghang ontoonto thethe boat,boat, andand thusthus bebe exposedexposed toto waveswaves andand coldcold--waterwater TestTest GarmentsGarments

„ FSFS FlightFlight SuitSuit „ WSWS WetWet SuitSuit „ BCBC BoatcrewBoatcrew coverallcoverall „ ACAC AircrewAircrew coverallcoverall „ NINI NavyNavy flightflight ensembleensemble –– intactintact „ NXNX NavyNavy flightflight ensembleensemble ---- torntorn 55 Ft.Ft. BreakBreak onon aa 2020 Ft.Ft. wavewave TestTest GarmentsGarments

„ FSFS FlightFlight SuitSuit „ WSWS WetWet SuitSuit „ BCBC BoatcrewBoatcrew coverallcoverall „ ACAC AircrewAircrew coverallcoverall „ NINI NavyNavy flightflight ensembleensemble –– intactintact „ NXNX NavyNavy flightflight ensembleensemble ---- torntorn CoolingCooling Rates,Rates, °°C.C. perper HourHour

6

5

4 Water 3 Raft 2 Boat

1

0 FS NX BC AC WS NI TakeTake HomeHome LessonsLessons

ƒ GetGet OutOut ofof thethe WaterWater !!!!

ƒ NoNo mattermatter whatwhat thethe weatherweather conditions,conditions, youyou’’rere almostalmost alwaysalways betterbetter offoff outout ofof thethe waterwater

ƒ WaterWater isis aa greatgreat conductorconductor ofof heatheat TakeTake HomeHome LessonsLessons

ƒ AirAir isis aa greatgreat insulatorinsulator

ƒ WindchillWindchill isis vastlyvastly overover--ratedrated asas aa riskrisk

ƒ GetGet OutOut ofof thethe WaterWater !!!! HeadHead CoolingCooling StudyStudy

„ TheThe headhead hashas alwaysalways beenbeen suspectedsuspected ofof beingbeing anan areaarea ofof highhigh heatheat loss.loss. „ NoNo previousprevious studiesstudies toto measuremeasure it.it. „ SomeSome PFDsPFDs cancan bebe wornworn suchsuch thatthat thethe backback ofof thethe headhead isis immersed.immersed. „ DoesDoes thisthis leadlead toto moremore rapidrapid coolingcooling andand thusthus aa shortershorter survivalsurvival time?time? „ DoesDoes headhead coolingcooling impactimpact mentalmental processes?processes? HeadHead CoolingCooling StudyStudy

„ 22 PFDsPFDs –– oneone wornworn withwith thethe backback ofof thethe headhead immersed,immersed, (head(head in,in, bodybody in);in); oneone wornworn withwith thethe headhead outout ofof thethe waterwater (head(head out,out, bodybody in).in).

„ Controls:Controls: drydry suitsuit withwith thethe headhead protectedprotected (head(head out,out, bodybody out);out); drydry suitsuit withwith thethe backback ofof thethe headhead immersedimmersed (head(head in,in, bodybody out)out) HeadHead CoolingCooling StudyStudy

FourFour permutationspermutations ofof headhead andand bodybody immersion:immersion:

HeadHead in,in, bodybody inin HeadHead in,in, bodybody outout HeadHead out,out, bodybody inin HeadHead out,out, bodybody outout PFDsPFDs PFDsPFDs PFDsPFDs inin 1010 DegDeg CC (50(50 DegDeg F)F) WaterWater

Head In, Body In Head Out, Body In DryDry SuitSuit inin 1010 DegDeg (50(50 DegDeg F)F) WaterWater

Head Out, Body Out Head In, Body Out HeadHead CoolingCooling ResultsResults

DropDrop inin CoreCore TemperatureTemperature (Deg.(Deg. C)C) AfterAfter OneOne HourHour

HeadHead Out,Out, BodyBody Out:Out: 0.10.1 HeadHead In,In, BodyBody Out:Out: 0.40.4 HeadHead Out,Out, BodyBody In:In: 1.41.4 HeadHead In,In, BodyBody In:In: 2.22.2 HeadHead CoolingCooling ResultsResults

TheThe increasedincreased coolingcooling raterate waswas relatedrelated toto thethe increaseincrease inin totaltotal bodybody surfacesurface areaarea immersedimmersed (dorsal(dorsal headhead andand neckneck andand upperupper anterioranterior thorax)thorax) ratherrather thanthan fromfrom increasedincreased heatheat flowflow throughthrough thethe head.head.

InIn otherother words,words, thethe headhead waswas NOTNOT foundfound toto bebe anan areaarea ofof disproportionatelydisproportionately highhigh heatheat flow.flow. HeadHead CoolingCooling ResultsResults

ThereThere waswas aa significantsignificant correlationcorrelation betweenbetween bodybody corecore temperaturetemperature andand mentalmental performanceperformance,, whenwhen allall thethe psychometricpsychometric datadata werewere pooled:pooled:

LowerLower corecore temperaturestemperatures producedproduced poorerpoorer thinking.thinking. TakeTake HomeHome LessonsLessons

„ TheThe onsetonset ofof hypothermiahypothermia inin waterwater immersionimmersion isis acceleratedaccelerated whenwhen thethe headhead isis immersed.immersed.

„ HeadHead--coolingcooling impactsimpacts thinking/judgmentthinking/judgment

„ PFDPFD designsdesigns shouldshould strivestrive toto preventprevent headhead immersion;immersion; survivalsurvival protocolsprotocols andand trainingtraining curriculacurricula shouldshould continuecontinue toto emphasizeemphasize headhead protection.protection. TheThe EndEnd