Chapter 15

1. Chapter 15 Physical and Environmental Hazards

2. Lesson Objectives (1 of 3) • List the body’s physiological changes during acclimatization. • Predict and prevent acute mountain sickness (AMS).

3. Lesson Objectives (2 of 3) • Assess and manage AMS, including high altitude pulmonary edema and high altitude cerebral edema. • Assess and manage cold weather injuries, including hypothermia, frostbite, immersion (trench) foot, and chilblains.

4. Lesson Objectives (3 of 3) • Assess and manage heat illnesses, including heat exhaustion, heatstroke, and heat cramps. • List lightning safety guidelines and know how to assess and manage injuries caused by lightning.

5. Overview • Altitude, extreme temperatures, wind, rain, and lightning cause injuries and illnesses that do not commonly occur in urban areas. © Simon Krzic/ShutterStock, Inc.

6. Acclimatization (1 of 2) • The physiological changes in the body that compensate for hypoxia at altitudes above 8,000 feet. • Best achieved through slow, progressive ascent. • Rate and depth of breathing increase to improve oxygen delivery to the blood.

7. Acclimatization (2 of 2) • Heart beats more quickly and strongly. • Bone marrow produces more red cells. • Number of capillaries increase.

8. Acute Mountain Sickness (1 of 10) • Travel above 8,000 feet results in lower levels of oxygen in the blood. • AMS strikes those who ascend too high too fast and those who have not acclimatized to high altitudes.

9. Acute Mountain Sickness (2 of 10) • Predicting AMS • Cannot predict who will suffer. • Those who have suffered AMS before are more likely to experience it. • Fitness and training offer no guaranteed protection.

10. Acute Mountain Sickness (3 of 10) • Prevention of AMS • Allow ample time to acclimatize at various levels of ascent. • High altitude climbing • Mild AMS can develop at 6,000 feet. • Above 13,000 feet, climbers should reach sleeping altitude about 1,000 feet higher than the previous day.

11. Acute Mountain Sickness (4 of 10) • High altitude climbing (continued) • Climbers who become sick and do not improve must descend 1,000 to 3,000 feet. • Drink 4 to 5 quarts of fluid daily. • Avoid alcohol, sedatives, and sleeping pills.

12. Acute Mountain Sickness (5 of 10) • Mild AMS • What to look for: • Headache that often develops at night • Unusual fatigue • Appetite loss and nausea • Restless sleep with irregular breathing • Shortness of breath with exertion • Swollen face with bags under the eyes

13. Acute Mountain Sickness (6 of 10) • Mild AMS • What to do: • Rest and do not go any higher. • Administer aspirin or acetaminophen. • If symptoms increase, descend. • Administer acetazolamide. • Give dexamethasone for severe headache. • Be alert for progression to severe altitude sickness.

14. Acute Mountain Sickness (7 of 10) • High altitude pulmonary edema (HAPE) • What to look for: • Shortness of breath • Cough producing frothy, blood-stained sputum • Rattling or crackling and moist breathing • Cyanosis • Rapid pulse

15. Acute Mountain Sickness (8 of 10) • High altitude pulmonary edema (HAPE) • What to do: • Descend. • Give oxygen. • Commence treatment in portable compression chamber. • Administer acetazolamide and/or nifedipine.

16. Acute Mountain Sickness (9 of 10) • High altitude cerebral edema (HACE) • What to look for: • Severe, constant throbbing headache • Incoordination • Extreme fatigue not relieved by rest • Hallucinations • Vomiting • Coma

17. Acute Mountain Sickness (10 of 10) • High altitude cerebral edema (HACE) • What to do: • Descend. • Treat for several hours in a portable hyperbaric bag. • Prop victim up to improve breathing. • Give 4 to 5 liters of fluid daily. • Administer acetazolamide and dexamethasone.

18. Cold Injury (1 of 20) • Cold injuries include hypothermia, frostbite, cold immersion injury, and chilblains. • Hypothermia is a general cooling of the body core that develops when the body’s temperature drops more than 2ºF. • Frostbite is freezing of skin and flesh.

19. Cold Injury (2 of 20) • Hypothermia • Exacerbated by inadequate clothing and exhaustion • Anxiety, injury, drugs, alcohol, and poor nutrition predispose people to hypothermia. • Wetness and wind chill can cause hypothermia in all seasons.

20. Cold Injury (3 of 20) • Hypothermia • Means of heat loss • Convection • Conduction • Evaporation • Radiation

21. Cold Injury (4 of 20) • Hypothermia • Sources of heat gain • Radiation • Exercise • Shivering • Food • Blood vessel constriction • Insulation

22. Cold Injury (5 of 20) • Mild hypothermia • What to look for: • Shivering • Uncharacteristic behavior • Stiff muscles and cramps • Cold, pale, and blue-gray skin

23. Cold Injury (6 of 20) • Mild hypothermia • What to do: • Find shelter. • Light a fire or stove. • Change or remove wet clothes and add dry layers. • Give food and hot drinks. • Allow shivering to continue inside a sleeping bag.

24. Cold Injury (7 of 20) • Mild hypothermia • What to do: • Give warm, sweet liquids. • Provide rest and warmth. • Never leave a hypothermic victim alone!

25. Cold Injury (8 of 20) • Severe hypothermia • What to look for: • No shivering • Behavior changing from erratic to apathetic to unresponsive • Stiff muscles and uncoordinated movement • Weak, slow, irregular pulse • Slow breathing • Coma, with dilated pupils

26. Cold Injury (9 of 20) • Severe hypothermia • What to do in the field: • Concentrate effort on reducing further heat loss. • Do not endanger other members of the party. • Shelter the victim. • Stop further heat loss. • Provide heat to the victim’s trunk. • Cover the victim’s head.

27. Cold Injury (10 of 20) • Severe hypothermia • What to do (rescue): • Leave at least one person with the victim. • Send for help. • Do not change your plan, even if victim improves. • If you must carry the victim out, insulate him or her well. • Choose the safest route.

28. Cold Injury (11 of 20) • Severe hypothermia • What to do (base camp): • If rescue is impossible or days away, use all available means to rewarm the victim slowly. • Do not try rapid rewarming. • Give plenty of warm, sweet liquids. • Do not place warm objects directly on the victim’s skin.

29. Cold Injury (12 of 20) • Deep hypothermia • Body core temperature falls below 82ºF. • Pupils can be dilated and fixed, the limbs stiff, and the skin icy. • Should attempt resuscitation if there is even a remote chance at recovery. • Only sure sign of death is failure to revive with rewarming.

30. Cold Injury (13 of 20) • Immersion hypothermia • Has rapid onset and a faster rate of cooling • Heat loss is 25 times faster in water than in air. • Can develop in less than an hour in water colder than 45ºF. • Begin CPR as soon as possible.

31. Cold Injury (14 of 20) • Frostbite • Localized freezing of tissues. • Contributing factors include: wetness, contact with metal, prolonged exposure, dehydration, poor nutrition, extremely cold temperatures, and immobilization.

32. Cold Injury (15 of 20) • Frostbite • Types of frostbite • Frostnip: Superficial injury involving the surface of the skin • Superficial frostbite: Involves all layers of skin but not underlying fat, muscles, or other tissue • Deep frostbite: Involves the skin and underlying tissues

33. Cold Injury (16 of 20) • Frostbite • What to look for: • White, waxy skin that has no feeling and is wooden to the touch • Possible thawing (skin is soft and body part can appear gray or purple; skin tingles painfully; blisters develop within a few hours.

34. Cold Injury (17 of 20) • Frostbite: What to do • Avoid a freeze-thaw-refreeze cycle. • Allow to thaw if more than 8 hours from help. • Keep clean and cover with dry dressing. • Elevate limb above the level of the heart.

35. Cold Injury (18 of 20) • Frostbite: What to do (continued) • If thawing is inevitable and/or if transportation is assured, warm in water 104–108ºF for 30 to 40 minutes. • Dry carefully. • Protect from further damage. • Evacuate.

36. Cold Injury (19 of 20) • Immersion (trench) foot • A nonfreezing cold injury caused by prolonged exposure to cold but without freezing. • Prevent by keeping feet warm and dry. • Treat by elevating the feet and exposing to air. • In severe cases, evacuate.

37. Cold Injury (20 of 20) • Chilblains • Caused by repeated exposure of bare skin to wet, wind, and cold. • Causes red, itchy, tender, swollen skin. • Prevent by wearing gloves.

38. Heat Illness (1 of 7) • The body balances heat loss against heat gain. • Evaporation of sweat dissipates heat, but fluid and salt are also lost. • Factors that can predispose one to heat illness: • Dehydration • Factors that limit the ability to sweat • Prior cardiovascular problems

39. Heat Illness (2 of 7) • Heat exhaustion: What to look for • Inability to continue exercise or work due to symptoms • Headache, dizziness, fatigue, nausea, and vomiting • Rapid pulse • Thirst and profuse sweating • Gooseflesh, chills, and pale skin • Low blood pressure with possible fainting

40. Heat Illness (3 of 7) • Heat exhaustion • What to do: • Rest and maximize air circulation. • Remove excess clothing. • Wet the victim with cold water. • Have victim drink fluids.

41. Heat Illness (4 of 7) • Heat exhaustion • What to do (continued): • In severe cases, add 0.25 tsp of salt and 6 tsp of sugar to 1 liter of water. • If body temperature is greater than 102ºF, seek medical care.

42. Heat Illness (5 of 7) • Heatstroke: What to look for • Headache • Drowsiness, irritability, unsteadiness, confusion, delirium, convulsions, coma • Rapid pulse • Low blood pressure • Dry or sweat-moistened hot skin • Body temperature greater than 106ºF

43. Heat Illness (6 of 7) • Heatstroke: What to do • Remove victim from heat. • Remove clothing. • Start immediate, rapid cooling. • Stop cooling when body temperature falls to 102ºF or when mental status improves. • Monitor temperature frequently.

44. Heat Illness (7 of 7) • Heat cramps • What to look for: • Cramps in the calf, thighs, or abdomen following exercise • What to do: • Stretch affected muscles. • Give salted fluids. • Do not give salt tablets.

45. Lightning Injury (1 of 4) • Kills by stopping the heart and breathing. • External injury and superficial and deep burns can occur.

46. Lightning Injury (2 of 4) • Lightning safety guidelines • Avoid: • Isolated tall trees, hilltops, power lines or pylons, small exposed shelters • Tents • Hill ridges and summits • Rock walls

47. Lightning Injury (3 of 4) • What to look for: • Loss of consciousness • Superficial steam burns • Shredded clothing or shoes that have been blown off • Blue, mottled limbs • Fractures or internal injuries

48. Lightning Injury (4 of 4) • What to do: • Check breathing. • CPR if necessary. • Check for injuries. • Give supportive care: Maintain airway, provide shelter, monitor vital signs. • Evacuate.