Strategies for Treating Hypothermia

How to deal with low core body temperature?

Joshua BennettM1073

Relevance to Wilderness Medicine Medical emergency

>50% mortality in patients aged 70 or older with temperature <32°C (Longmore et al.,

2010)

Personal experience

Why I chose to talk about this

1 hour from car park, notice young man slumped against stone wall.

Mumbling inaudibly and shivering violently.

Half empty bottle of vodka. Equipment is your backpack

containing what you would normally take for a day outdoors.

What would you do?January 2011, Lake District, Sca Fell

Grades and types of hypothermia Need to know basics in order to treat.

Essentials of hypothermia management Do’s and Don'ts

Strategies to treat hypothermia Spontaneous rewarming Active external rewarming Active core rewarming

Resuscitation and hypothermia

Objectives

Severity Grade I – conscious and shivering Grade II – impaired consciousness /

no shivering Grade III – unconscious or cardiac

instability Grade IV – apparent death

Grades of hypothermia

KEY POINT: Cold patients who have stopped shivering will cool at an

accelerating rate (due to minimal heat generation).

Severity Grading system

Speed of onset Acute / immersion

Subacute / exhaustion / injury

Subchronic / urban

Types of hypothermia

irwayreathingirculationisability

Where hypothermia management fits

ABCD

Environment / evacuation

Hypothermia physiology

KEY POINT: ‘Core afterdrop’ or ‘rewarming collapse’ can occur if rewarming is too

quick.

Do: Remove from

cold Replace wet

clothing Insulate Handle gently Monitor regularly

For any hypothermic patient...

Don’t: Suppress

shivering Give alcohol Put in warm

shower/bath Warm peripheries

KEY POINT: Sudden movements may trigger ventricular fibrillation.

(NESRA Medical Sub-Committee, 2010)

Spontaneous rewarming

May reverse Grade I hypothermia

Requires patient to generate heat

Layer system Insulate from

ground Cover head and

neck (leave airway!)

‘Hypothermia wrap’

Active external rewarming

Indications: Grade II hypothermia or worse Trauma or other co-morbidity

Apply heat source to armpits, groin and flanks

Should be warm not hot- risk of burning patient

Airway warming Air humidifier devices Warm tubing in warm drink

Warmed IV fluids Microwave Can warm giving set in warm drink

Thoracic lavage Peritoneal dialysis Cardiopulmonary bypass

Active core rewarming

invasive

(Danzl and Lloyd, 2001)

Check carefully for pulse for 1 minute

“No-one is dead until they are warm and dead” >33°C

Resuscitation and hypothermia

“Active core rewarming techniques are the primary therapeutic modality in hypothermia victims in cardiac arrest or unconscious with a slow heart rate.”

(Emergency Cardiac Care Committee, 1992)

1 hour from car park, notice young man slumped against stone wall.

Mumbling inaudibly and shivering violently.

Half empty bottle of vodka. Equipment is your backpack

containing what you would normally take for a day outdoors.

What would you do?January 2011, Lake District, Sca Fell

Summary

KEY POINT: Cold patients who have stopped shivering will cool at an

accelerating rate (due to minimal heat generation).KEY POINT: ‘Core afterdrop’ or ‘rewarming

collapse’ can occur if rewarming is too quick.

KEY POINT: Sudden movements may trigger ventricular fibrillation.

References Danzl, D. F. and Lloyd, E. L. (2001) Medical

Aspects of Harsh Environments. Borden Institute. Emergency Cardiac Care Committee. (1992)

'Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiac Care', Journal of the American Medical Association.

Longmore, M., Wilkinson, I. B., Davidson, E. H., Foulkes, A. and Mafi, A. R. (2010) Oxford Handbook of Clinical Medicine.8th ed:

NESRA Medical Sub-Committee. (2010) Mountain Rescue for Casualty Care student notes.2nd ed:

Questions?