Cold Injuries

Donald Pelto, DPM

Central Massachusetts Podiatry

Worceter, MA

How We Lose Heat

• Radiation – loss of heat to the environment due to temperature gradient

• Conduction – through direct contact between objects– Water conducts heat away 25 times faster than

air (Stay dry = stay alive!)

– Steel conducts heat away faster than water

How We Lose Heat – 2

• Convection – contact with something that is in motion– Wind Chill – the air is

moving around and causes greater heat loss

• Evaporation – heat loss from converting water from a liquid to a gas– Perspiration can be due to

sweating and breathing

Hypothermia – decrease in the core body temperature to a level

at which normal muscular and cerebral functions are impaired.

Heat + Heat – Cold = Hypothermia

Retention Production Challenge

Insulation

Body Fat

Surface to Volume Ratio

Exercise

Shivering

Temperature

Wetness

Wind

How to regulate core temperature

• Vasodilation / Vasoconstriction

• Sweating / Shivering

• Increasing / Decreasing Activity

• Behavioral Responses – removing or applying layers of clothing

Core

Periphery

Conditions leading to hypothermia

• Cold Temperature• Improper clothing

and equipment• Wetness• Fatigue, exhaustion• Dehydration• Poor food intake• Alcohol intake – causes vasodilation and heat loss

Signs and symptoms of hypothermia

• Watch for “Umbles”– Stumbles– Mumbles– Fumbles– Grumbles

• They show change in motor coordination and levels of consciousness

Levels of hypothermia

• Mild – core temperature 98.6 – 96 degrees F– Shivering– Unable to perform complex motor functions– Vasoconstriction to periphery

• Moderate - core temperature 95 – 93 degrees F– Dazed consciousness

– Loss of fine motor coordination – zipping coat

– Slurred speech

– Violent shivering

– Irrational behavior – taking off clothing

– “I don’t care attitude”

• Severe - core temperature 92 – 86 degrees F– Shivering occurs in waves – less to conserve

energy– Fall to ground, can’t walk, fetal position– Muscle rigidity – lactic acid and CO2 buildup– Skin is pale– Pupils dilate– Pulse decreases

How to assess hypothermia

• Shivering can be stopped voluntarily = mild hypothermia

• If can’t be stopped = moderate

• If you can’t get a radial pulse at the wrist

• Curled in fetal position • Can’t count backward

from 100 by 9’s

Treatment

• Reduce Heat Loss– More layers

– Dry clothing

– Increase Physical Activity

– Shelter

• Add Fuel and Food– Carbs, Proteins, Fats

– Hot liquids, Sugars

• Avoid– Alcohol – vasodilator,

causes peripheral heat loss

– Caffeine – a diuretic causes water loss and dehydration

– Tobacco – a vasoconstrictor, increase risk of frostbite

• Add heat– Fire

– Body to body contact

Hypothermia Wrap

Cold Injuries

• Frostnip

• Frostbite

• Trench Foot

• Eye Injuries

Frostnip

• Freezing of tip layers of skin tissue

• Reversible• Top layer hard and

rubbery but deeper tissue is still soft

• Numbness• Seen on cheeks, earlobes,

fingers, toes• Treatment – warm

slowly, do not rub the area

Frost Bite

• Skin is white and “wooden” feel

• Includes all skin layers

• Numb or no feeling

• Can freeze muscle or bone

• Treatment – rewarm by immersion is water bath, don’t use dry heat, avoid from refreezing

Frost Bite

Trench Foot – Immersion Foot

• Prolonged exposure of the feet to cool, wet conditions.

• Wet feet lose heat 25x faster than dry

• Treatment – Gentle rewarming, do not walk on foot

Eye Injuries

• Freezing of Cornea– Forcing eyes open during

strong winds without goggles

– Treatment – rapid warming

• Eyelashes freezing together

• Snowblindness– Sunburn of the eyes, occurs

8-12 hours after– Treatment – wear

sunglasses or goggles

The End

Burns

Maggot Therapy

Trauma

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Ulcer