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Lecture given to EMTs on cold injures. Focus on foot problmes. www.drpelto.com
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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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