Chapter 20

1. Chapter 20 Cold-Related Emergencies

2. Cold-Related Emergencies • Normal body temperature is 98.6°F. • Body loses heat when surrounded by air or water that is cooler than the body. • Body temperature falls • Cold injuries can result.

3. How Cold Affects the Body (1 of 2) • Biologic defense mechanisms protect body • Vasoconstriction • Tightening of blood vessels • Can cause discomfort, numbness, loss of dexterity, cold injuries • Shivering produces body heat. • Stops when core temperature falls too low or when there is no fuel.

4. How Cold Affects the Body (2 of 2) • Physical activity produces heat. • Heat loss after exertion if clothes are wet • Proper hydration and nutrition help prevent cold injuries. • The colder the temperature, the greater the potential of body heat loss. • Physical changes from cold exposure can impair ability to perform manual tasks.

5. Heat Loss From the Body (1 of 2) • Body temperature maintained by balance of heat production and loss • Shivering rapidly consumes calories. • Heat loss occurs primarily through skin.

6. Heat Loss From the Body (2 of 2) • Four mechanisms of heat loss: • Conduction • Direct contact with colder object • Convection • Loss of heat by air blowing over skin • Evaporation • Conversion of liquid on skin to vapor • Radiation • Heat given off to cooler air • Primary method of heat loss

7. Susceptibility to Cold Injury • Physically unfit • Dehydration • Very lean people • Elderly • Alcohol, caffeine • Smoking, chewing tobacco • Inadequate nutrition, illness, injury • Previous cold injury

8. Effects of Altitude • Temperature, windchill are considerations • Air temperature drops 3.6°F every 1,000 feet. • Winds more severe • More susceptible to frostbite above 8,000 feet

9. Effects of Water • Conducts heat away from body faster than air. • Body heat loss occurs 25 times faster with wet clothing. • Plunging into cold water can cause irregular heartbeat, gasping, hyperventilation. • These can cause water inhalation, heart failure, drowning.

10. Effects of Wind • Increases potential for body heat loss • Windchill index integrates wind speed and air temperature. • Helps estimate risk of cold injury. • Artificial wind can increase heat loss.

11. Effects of Metal and Liquid Fuels • Can conduct heat away from skin rapidly. • Contact can cause almost instantaneous freezing. • Must use great care when handling.

12. Minimizing Effects of Cold on the Body • Adequate clothing is key • Layered clothing helps maintain proper body temperature. • Undergarments • Should wick away perspiration • Middle layer • Synthetic pile, fleece, or wool • Outer layer • Waterproof, wind resistant, breathable, with zipper

13. Nonfreezing Cold Injuries • Can occur when conditions are cold and wet, hands and feet cannot be kept warm and dry • Chilblain • Trench foot

14. Chilblain • Painful, but causes little or no permanent damage • Can develop in 3 to 6 hours if exposed to cold and moisture

15. Recognizing Chilblain • Swollen skin • Tender, hot to touch, itchy • Blisters • Aching, prickly sensation • Numbness

16. Care for Chilblain • Get victim out of cold.

17. Trench Foot • Serious injury, also called immersion foot • Develops when feet exposed to moisture and cold for 12 hours or longer • Moisture softens skin, tissue loss and infection occur • Crippling injury can occur

18. Recognizing Trench Foot • Itching, numbness, tingling pain • Swollen feet, pale skin cold to touch • Red, bluish blotches on skin • Sometimes open weeping, bleeding

19. Care for Trench Foot • Dry the skin. • Rewarm foot gradually. • Cleanse weeping areas with mild soap and water, apply breathable dressings.

20. Freezing Cold Injuries • Occur when air temperature is below freezing (32°F) • Frostnip • Freezing is limited to skin surface • Frostbite • Freezing occurs deeper in skin • Frostbite more common in military, mountain climbers, explorers.

21. Frostnip • Water freezes on skin surface • Serious — could signal impending frostbite

22. Recognizing Frostnip • Red, swollen skin • Painful • Dry, cracked, sensitive skin from repeated frostnip to same spot

23. Care for Frostnip • Gently warm affected area. • Place against warm body part. • Blow warm air on area. • After, area can become red and tingling. • Do not rub.

24. Occurs when temperatures drop below freezing Tissue can actually freeze Blood supply obstructed Affects feet, hands, ears, nose Most severe consequence = gangrene (dead tissue) Frostbite

25. Recognizing Frostbite (1 of 2) • White, waxy, or grayish yellow skin • Cold and numb • Tingling, stinging, aching • Stiff or crusty surface, soft underneath • Deep frostbite: • Cold, hard, solid • Blistering • Cold, pale, waxy skin • Pain stops

26. Recognizing Frostbite (2 of 2) • First-degree • Warm, swollen, tender • Second-degree • Blisters minutes to hours after thawing, enlarge over several days • Third-degree • Small blisters, reddish blue/purplish fluid • Fourth-degree • No blisters, no swelling • Numb, cold, white to dark purple

27. Care for Frostbite (1 of 2) • Get victim to warm area. • Remove wet clothing. • Remove items that could impair circulation. • Seek medical care. • If affected part is partially thawed or victim is remote: • Place part in warm water. Add warm water to maintain water temperature. • Ear or facial injuries: apply warm, moist cloths.

28. Care for Frostbite (2 of 2) • After thawing: • Place on stretcher if feet affected. • Protect area from contact with clothing, bedding. • Place dry dressings between toes and fingers. • Slightly elevate to reduce pain and swelling. • Apply aloe vera gel. • Provide aspirin (adults), or ibuprofen, or acetaminophen.

29. Hypothermia (1 of 3) • Life-threatening condition when core temperature falls below 95°F • Can occur even when temperature is above freezing, if windy, wet, or person is inactive • Can occur year round • Death results if untreated • Occurs rapidly during cold water immersion

30. Hypothermia (2 of 3) • Heartbeat, breathing, response to pain may not be detectable • Victim can still be alive. • Check circulation for 30-45 seconds. • Start CPR immediately if immersion occurred. • Handle gently. • Must be evaluated by physician.

31. Hypothermia (3 of 3) • Many different people susceptible. • Consider when behavior, history, and weather conditions indicate heat loss. • More likely if behavior is strange and victim was shivering. • Alcohol, medications can contribute • Very old, very young, and less fit are more susceptible

32. Types of Exposure • Acute • Heat loss occurs rapidly (6 hours or less) • Usually in water • Subacute • Heat loss over 6-24 hours • Land or water • Chronic • Long-term cooling greater than 24 hours • Occurs on land

33. Recognizing Hypothermia • Suspect in anyone with temperature less than 95°F. • Change in mental status: • Disorientation, apathy, changes in personality • Shivering • Cool abdomen • Low core body temperature (rectal)

34. Types of Hypothermia • Mild to severe based on core body temperature • In severe cases, shivering stops. • Do not start CPR if: • Core body temperature less than 60°F • Chest is frozen. • Submerged more than 60 minutes • Lethal injury • Transport delayed • Rescuers endangered

35. Recognizing Mild Hypothermia • Vigorous, uncontrollable shivering • Grumbling, mumbling, fumbling, stumbling • Cool or cold skin on abdomen, chest or back • Core body temperature above 90°F

36. Care for Mild Hypothermia • Get victim out of cold. • Handle gently. • Replace wet clothing with dry clothing. • Cover head. • Cover with vapor barrier. • Keep victim horizontal. • Do not raise legs. • Do not let victim walk or exercise. • Call 9-1-1. • Allow shivering.

37. Recognizing Severe Hypothermia • No shivering • Ice cold, blue skin • Stiff, rigid muscles • Altered mental status, not alert • Slow breathing and pulse • Victim might appear dead • Core body temperature below 90°F

38. Care for Severe Hypothermia • Get victim out of cold. • Handle gently. • Replace wet clothing with dry clothing. • Cover head. • Cover with vapor barrier. • Keep victim horizontal. • Do not raise legs. • Do not let victim walk or exercise. • Call 9-1-1. • When remote, warm by any available heat source.

39. Adding Heat • Problems with rewarming: • Warm water immersion requires a lot of warm water and a bathtub. • Hot baths can cause cardiac arrest. • Body-to-body contact in insulated sleeping bag is ineffective. • Use body-to-body rewarming only when delayed care or other methods unavailable. • Chemical heating pads are not effective.

40. Dehydration • In cold weather, fluid is lost through exhaled breath. • Color and volume of urine indicate hydration. • Unmelted snow and ice should not be consumed; can lower body temperature. • If snow, ice are only available sources of water, melt before consuming. • Melted snow, ice should be disinfected before drinking.