HYPOTHERMIAHYPOTHERMIA

Dr. Josep Vidal AlaballDr. Josep Vidal Alaball

““No previously healthy No previously healthy person should die of person should die of

hypothermia after he has hypothermia after he has been rescued and been rescued and

treatment has been treatment has been started”started”

Cameron C.Bangs, M.D. The Mountaineers Cameron C.Bangs, M.D. The Mountaineers 19861986

DEFINITIONDEFINITION

Body temperature Body temperature < 35ºC< 35ºC with low with low reading rectal thermometerreading rectal thermometer

CAUSESCAUSES Exposure to adverse environments: wet and windy Exposure to adverse environments: wet and windy

conditionsconditions Immersion in cold waterImmersion in cold water

Risk increases by drug/alcohol Risk increases by drug/alcohol ingestion, illness or injury.ingestion, illness or injury.

Elderly & very young: more susceptible.Elderly & very young: more susceptible.

ACTIONS TO ALL DE PATIENTSACTIONS TO ALL DE PATIENTS

A B CA B C Remove wet clothingRemove wet clothing Patient dried and covered with blankets or Patient dried and covered with blankets or

insulating equipmentinsulating equipment Maintain horizontal positionMaintain horizontal position Avoid rough movement and excess Avoid rough movement and excess

activityactivity Monitor core temperature and cardiac Monitor core temperature and cardiac

rhythm.rhythm.

ASSESS RESPONSIVENESS, ASSESS RESPONSIVENESS, BREATHING AND PULSEBREATHING AND PULSE

Pulse/Breathing Pulse/Breathing absent: Start absent: Start CPRCPR

Pulse/Breathing Pulse/Breathing present: present: RewarmingRewarming

34ºC - 36ºC34ºC - 36ºC (mild hypothermia)(mild hypothermia) Passive rewarmingPassive rewarming Active external rewarmingActive external rewarming

30ºC - 34ºC30ºC - 34ºC (moderate hypothermia)(moderate hypothermia) Passive rewarmingPassive rewarming Active external rewarming of truncal Active external rewarming of truncal

areas onlyareas only

< 30ºC< 30ºC (severe hypothermia)(severe hypothermia) Active internal rewarmingActive internal rewarming

WHAT IS CORE TEMPERATURE ?WHAT IS CORE TEMPERATURE ?

REWARMINGREWARMING PASSIVE REWARMINGPASSIVE REWARMING

– Blankets, insulating equipmentBlankets, insulating equipment ACTIVE EXTERNAL REWARMINGACTIVE EXTERNAL REWARMING

– Heated blanketsHeated blankets– Warm bath (up to 40ºC)Warm bath (up to 40ºC)

ACTIVE INTERNAL REWARMINGACTIVE INTERNAL REWARMING– Warm, humidified oxygenWarm, humidified oxygen– Warm i.v. fluidsWarm i.v. fluids– Gastric, peritoneal or pleural lavage with warm fluids Gastric, peritoneal or pleural lavage with warm fluids

(at 40ºC)(at 40ºC)– Blood rewarming by haemodialysis or Blood rewarming by haemodialysis or

cardiopulmonary bypass.cardiopulmonary bypass.

DECISION TO RESUSCITATEDECISION TO RESUSCITATE Beware of pronouncing death in patients with Beware of pronouncing death in patients with

hypothermia! hypothermia! Death should not be confirmed until patient Death should not be confirmed until patient

has warmed to a temperature > 33ºC, or has warmed to a temperature > 33ºC, or attempts to raise core temperature have failed.attempts to raise core temperature have failed.

Cold itself may produce a very slow, small Cold itself may produce a very slow, small volume and irregular pulse with unrecordable volume and irregular pulse with unrecordable BP.BP.

Hypothermia confers a degree of protection to Hypothermia confers a degree of protection to vital organs. Associated arrhythmias are vital organs. Associated arrhythmias are potentially reversible.potentially reversible.

Resuscitation has to be prolonged.Resuscitation has to be prolonged.

RESUSCITATIONRESUSCITATION

Open, clear and maintain airway.Open, clear and maintain airway. If no respiration ventilate with high If no respiration ventilate with high

concentration of warm, humid concentration of warm, humid oxygen.oxygen.

Pulse can be very slow. Palpate a Pulse can be very slow. Palpate a major artery for a minimum 1 min.major artery for a minimum 1 min.

Consider hypothermia as a cause of Consider hypothermia as a cause of bradycardia in any casualty.bradycardia in any casualty.

RESUSCITATIONRESUSCITATION

Rates for ventilation and chest Rates for ventilation and chest compression as for normothermic compression as for normothermic patient, but hypothermia may patient, but hypothermia may cause stiffness of the chest wall.cause stiffness of the chest wall.

Cannulate a central or large Cannulate a central or large proximal vein.proximal vein.

Infuse warm N-Saline.Infuse warm N-Saline.

ARRHYTHMIASARRHYTHMIAS

As body temperature falls:As body temperature falls:– Sinus bradycardiaSinus bradycardia– Atrial fibrillationAtrial fibrillation– Ventricular fibrillationVentricular fibrillation– AsystoleAsystole

Standard treatment protocols should be Standard treatment protocols should be followed.followed.

ARRHYTHMIASARRHYTHMIAS

If core T.< 30º If core T.< 30º VFVF may not respond to may not respond to cardioversioncardioversion. . Rapid core rewarming is necessary Rapid core rewarming is necessary with CPR being continued until defib. becomes with CPR being continued until defib. becomes effective.effective.

LignocaineLignocaine no significant effect on VF in no significant effect on VF in hypothermic patients.hypothermic patients.

Mechanical disturbanceMechanical disturbance ( (tracheal intubation, tracheal intubation, excessively vigorous chest compressionsexcessively vigorous chest compressions) can ) can precipitate VF until core T. is raised.precipitate VF until core T. is raised.

Other arrhythmiasOther arrhythmias tend to revert spontaneously tend to revert spontaneously as core T. rises, and usually do no require as core T. rises, and usually do no require immediate treatment.immediate treatment.

INVESTIGATIONSINVESTIGATIONS

ABG’sABG’s Electrolyte & glucoseElectrolyte & glucose CXRay*CXRay* Check for underlying illness or traumaCheck for underlying illness or trauma TFTTFT Urine outputUrine output* * Stomach should be decompressed with a Stomach should be decompressed with a

nasogartric tube to reduce respiratory nasogartric tube to reduce respiratory complications.complications.

PROGNOSISPROGNOSIS

Neurological recovery still possible Neurological recovery still possible after prolonged cardiac arrest, as after prolonged cardiac arrest, as hypothermia reduces cerebral hypothermia reduces cerebral oxygen requirements.oxygen requirements.

Prognosis usually determined by Prognosis usually determined by severity of underlying illness.severity of underlying illness.

THE ENDTHE END