COLD INJURY

1. COLD INJURY

2. Types of Cold Injury • Nonfreezing (see back up slides for details) • Chilblains • Trench foot • Freezing • Frostbite • Hypothermia • Cold injury occurs on a spectrum

3. Frostbite • Injury resulting from freezing and ice crystal formation in skin/underlying tissues • Superficial, injury contained within skin layers: • Skin is red, progressing to pale-white and firm to the touch • Cold sensation, tingling, itching, burning or numbness • Superficial blisters with clear/milky fluid, surrounded by redness and swelling can develop post rewarming • Deep, may extend to muscles/bone: • Skin is white-yellow and waxy in appearance & hard to the touch • Decreased sensation, affected body part feels clumsy or absent • Swelling, deep blisters contain bloody fluid and skin turning purplish-blue will develop post rewarming • Patients with frostbite will experience severe pain on rewarming

4. Frostbite Decision Making • If within 2 hours of definitive medical care, evacuate and delay rewarming • Injury may thaw spontaneously – do not deliberately keep frozen • If more than 2 hours from a hospital, rewarm if refreezing can be prevented • Thawed tissue that refreezes almost always dies! Passive Frostbite Rewarming • Active, rapid rewarming w/warm water immersion is the preferred method • See back up slides for details • If active rewarming is not possible and thawing is required • Move patient to warm shelter such as a tent or cabin • Warm affected tissues with skin to skin body heat such as placing hand into armpit or foot against caregiver’s abdomen

5. First Aid for Frostbite • Remove wet, constrictive clothing and jewelry • Handle frostbitten tissue gently and protect it from injury • Do not allow use of frozen or thawed tissue unless mandatory for individual or group safety • Apply clean, dry padding between fingers/toes/around frozen tissue • If available, apply topical aloe vera to thawed tissue before applying dressings • Use ibuprofen for pain control • Elevate thawed extremities to reduce subsequent swelling

6. Cautions for Frostbite • Do not rub the frozen part or apply ice or snow • Do not attempt to keep tissue frozen to prevent spontaneous thawing • Do not attempt to thaw in cold water • Do not attempt to thaw w/direct heat sources such as stoves/fires • Do not allow patient to use alcohol/tobacco • Do not break blisters in the field • Never attempt rewarming if refreezing is likely – it is better to walk out on frozen feet than to have them refreeze • But do not allow walking on frostbitten feet unless required for individual or group safety • Previous frostbite injury usually results in increased sensitivity to cold, requiring additional care in maintain warmth and minimize cold exposure

7. Prevention of Frostbite • Maintain good physical fitness • Dress in layered clothing and properly fitting shoes; cover all exposed skin • Wear mittens instead of gloves in severe cold • Keep feet and hands dry • Consider use of small chemical heat packs • Maintain proper hydration and nutrition • Avoid alcohol and tobacco • Terminate exposure/seek shelter if weather worsens • Check your teammates face’s for signs of frostbite (white patches) • Repeatable inquire on the status of your teammates feet and hands

8. Hypothermia Body Temperature Regulation • Conduction: heat is transferred to cooler objects • Limit direct body contact with cold objects; use insulation • Convection: body heats air around it • Warm air is moved away by wind • Maintain barrier against wind and get out of elements • Radiation: body gives and receives heat • Dark clothes accept more heat from sunlight • Evaporation: sweating results in heat loss • Layer clothes to prevent overheating and sweating • Decrease in the body’s core temperature below 95⁰F (35⁰C)

9. Basic Treatment for all Stages of Hypothermia • Prevent further heat loss • Insulate person from the ground • Protect from the wind • Replace wet clothes with dry ones • Cover person with vapor barrier such as tarp • Move person to warm environment Stages of Hypothermia • Mild: Patient alert and shivering • Moderate: Patient drowsy, not shivering • Severe: Patient unconscious • Profound: Patient not breathing

10. Mild Hypothermia Treatment • Mild hypothermia, patient is alert & shivering • Shivering is a very effective method of generating body heat • Patients can be rewarmed with dry insulation as long as they are shivering • Light exercise is helpful for mild hypothermia • If alert and able to drink, provide fluids containing sugars to fuel shivering Critical Distinction!Alert & Shivering = MildNot shivering = Moderate or Worse

11. Moderate to Severe Hypothermia Treatment • Moderate: Patient drowsy, not shivering • Severe: Patient unconscious • Treat patient very gently, vigorous stimulation or changes in position (supine to sitting/standing) may cause cardiac arrest • Do not attempt to increase heat production through exercise • Do not allow patient to drink fluids unless able to hold container • The non-shivering hypothermia patient needs external heat to rewarm • Small chemical hot packs & skin-to-skin contact with a warm body in sleeping bag are generally insufficient for rewarming hypothermia patients, but can be helpful to prevent additional heat loss • Larger heat sources such as hydration bladder filled w/hot water, wrapped w/cloth to prevent burns, can be useful when placed with person in sleeping bag

12. Constructing a Hypothermia Wrap • Place tarp on ground to act as vapor barrier • Place sleeping pad on tarp as insulation from ground • Place sleeping bag atop sleeping pad • Place patient into sleeping bag • Fold corner of tarp across feet • Fold other side of the tarp around the patient • Fold one side of the tarp around the patient

13. Prevention of Hypothermia • Wear proper clothing to keep warm and dry • Layer clothing to prevent overheating and sweating • Stay out of the wind • Terminate exposure: keep warm and dry, seek shelter • Hydrate properly and maintain nutrition • Avoid alcohol and drugs in wilderness Groups at Risk for Cold Injury • Infants: do not conserve heat as well as adults • Elderly: lower metabolism produces less heat • Physically unfit or ill: decreased energy stores • Alcohol: dilates blood vessels, which increases heat loss; causes poor judgment • Trauma: decreased physical activity, laying on cold ground, blood loss • Persons improperly dressed, dehydrated or lacking proper food

14. Dressing for the Cold • No cotton clothing; choose wool or synthetics that wick moisture, dry quickly and maintain insulating properties when wet • Layer clothes, add layers for increased warmth, remove layers to avoid sweating • Wear breathable water/wind resistant shell as outer layer • Ensure proper fit of shoes • Wear hat and gloves/mittens; cover all exposed skin using face mask / scarf / gaiter / goggles

15. Other Preventive Principles • Appoint group leader or use buddy system to ensure individual safety and welfare • Check each others faces for signs of frostbite (white patches) • Repeatable inquire on the status of your “buddies” feet and hands • Avoid the outdoors during extreme weather and terminate exposure/seek shelter if unable to stay warm • Carry first aid kit, food, water, extra clothes, and means for shelter & fire starting • Leave trip plan with someone and develop procedures for if/when you become overdue • Carry means of communication, such as a cell phone or emergency beacon • Keep these devices warm (inside your jacket) and powered down when not in use

16. Winter Clothing & Pack Considerations • Pack, 40 – 50 liters / 2,500 – 3,100 cubic inches • Boots, insulated & water proof • Gaiters NO COTTON, all items wool or synthetic • Wool socks (I’ve not found a good synthetic option) • Extra socks (optional) • Light / medium weight base layers, top/bottoms – wool is my 1st choice • Extra top base layer (optional - prone to sweating?) • A) Insulated pants - soft shell / Fleece / wool (optional) • B) Hard shell pants - breathable wind/water proof, preferably w/full side zips (optional) • Use A or B, or A + B • Insulating top layer: Soft shell / Fleece / wool - jacket / sweater • Insulating top layer: Soft shell / Fleece / wool – vest / sweater (optional) • Hard shell jacket w/hood: breathable wind/water proof, preferably w/pit zips • Insulated jacket: down / synthetic / wool – preferably large enough to fit over shell & existing layers • Down is great IF your confident you can keep it dry!! Best insulator / weight • Synthetic, Primaloft is my 1st choice • Wool, heavy • 2 Hats: fleece / wool – 1 light weight & 1 heavy weight • Balaclava / face mask / scarf / gaiter: fleece / wool (optional) • Goggles (optional) • 2 pair of gloves: synthetic / wool / fleece with shell • Mittens: synthetic / wool / fleece with shell (optional)

17. Winter Clothing & Pack Considerations – continued • Snowshoes / skis / micro-spikes • Ski poles(optional) • Food & water for 24 hrs: • high calorie foods that are not impacted by freezing (trail mix, granola bars, etc.) • thermos w/hot non-caffeinated & sweetened beverage (tea & honey, jell-o, Gatorade, etc…) • Insulated water bottle container • Map / compass / GPS + extra batteries, Lithium batteries for temps below zero • Whistle • 2 headlamps + extra batteries (extra bulbs if not LCD), Lithium batteries for temps below zero • First aid kit: personal • Trail tape / flagging • Pencil / pen & notebook / paper • Matches / lighter • Fire starting material • Knife • Small folding saw (optional) • Space blanket / light weight tarp / bivy bag • heavy duty trash bag, 1-2 • Chemical hot packs: 4-6 • Light weight cord, 20-40 feet • Chemical Light sticks (optional) • Light weight sleeping bag (optional) • Ensolite pad (optional), best if a removable component of your packs suspension system

18. Questions? Always seek professional medical evaluation and treatment for hypothermia and other cold injuries! Back up slides follow

20. Active Frostbite Rewarming: • Immersion for about 30 minutes in a circulating warm water bath (104-108⁰F) is ideal if the thawed tissue can be kept in a warm environment afterwards • Ensure that the water is not too hot before inserting affected tissue – DO NOT allow burns • Do not towel dry; let tissue dry in warm air • Thawing may cause severe pain, requiring narcotics to control

21. Nonfreezing Cold Induced Injuries - Chilblains • Localized, inflammatory, bluish red lesions • Develop within several hours of usually brief exposure to cold • Intense itching, burning, or pain; aggravated by heat • Normally resolve within days to three weeks • Prevention • Minimize any cold exposure if prior history of chilblains • First Aid • Dry and gently massage affected skin • DO NOT expose to direct heat or hot water to rewarm • Ibuprofen for pain control

22. Nonfreezing Cold Induced Injuries – Trench Foot • Prolonged exposure to cold, wet conditions (32 – 59⁰F) • Pale, cold tissue, and numbness • Followed by redness, swelling, and pain after rewarming • Pain aggravated by heat and dependent position • Prevention • Maintain body core temperature and blood flow to feet by remaining active • Change socks frequently and keep feet dry • Wear proper sized shoes; do not lace tightly • First Aid • Rewarm body core, but not affected extremities • Elevation and ibuprofen for pain control • DO NOT rub affected tissue