HEAT INJURIES Types of Heat Injury l Heat

HEAT INJURIES

Types of Heat Injury l Heat Cramps l Heat Exhaustion l Heat Stroke

Heat Cramps l Painful cramping of the larger muscle groups ä l Due to excessive loss of salt through heavy sweating plus several hours of sustained exertion ä l legs, arms, abdomen acclimatization decreases risk Treatment ä ä ä shaded area massage arms/legs to increase circulation 0. 1% salt solution orally (1/2 tsp salt in 1 -qt. Water), sports drink, or salted food (MRE) plus fluid

Heat Exhaustion l Symptoms: ä ä l Cause: ä l heavy sweating, headache, light-headed, nausea/vomiting, tingling sensations Temperature 99 -104 F dehydration plus excessive salt depletion Treatment: ä ä ä shaded environment; loosen clothing If suspect early heat stroke, treat as such oral fluids if can drink ä ä ä cold water, 0. 1% salt solution, or 6% carbohydrate beverage 1 -2 liters over 2 -4 hours EVAC

Heat Stroke l Symptoms: ä ä l l elevated temperature plus central nervous system disturbance absence of sweating is a late finding Can begin as heat exhaustion and progress End-organ damage: ä ä brain damage, kidney failure, liver failure, blood clotting abnormalities related to duration of elevated temperature

Treatment of Heat Stroke l ABC ä ä l Lower the body temperature as fast as possible! ä ä ä l Unconscious patient may vomit and aspirate IV: no more than 2 L unless circulatory collapse All clothes off Cool water with fanning. . . increase evaporation Ice packs under groin or axilla EVAC. . . open doors/windows in helicopter/vehicle keep cooling to temp 101 -102 F. Ice-water immersion: controversial ä ä USASOC and TB MED do not recommend Wilderness Medicine, 3 rd ed. supports

Risk Factors for Heat Stroke l Dehydration ä ä ä l Respiratory and GI illnesses most common Alcohol use Laxatives and diuretics Medications ä Increase heat production and/or decrease heat loss ä ä Decrease sweating ä l pseudoephedrine, thyroid hormone, cocaine antihistamines (Benadryl), anti-nausea (meclazine, phenergan) Supplements ä Ephedrine (Ma. Huang), caffeine

Control Measures l Water and sports drinks l Salt l Acclimatization

OTSG Guidance for the Field Use of Sports Drinks l l Cool water is usually the best rehydration fluid Prolonged training and operational scenarios ä carbohydrates and electrolytes are also required for optimal physical and mental performance ä l meals and snacks plus water are best When sports drinks are appropriate: ä ä ä duration > 6 hours, hot weather, if snacks/meals not consumed duration > 3 hours, strenuous exercise, if snacks, meals not consumed duration > 6 hours strenuous exercise, if total food intake is significantly limited

Sports Drink Recommendations INGREDIENT Sodium Potassium Carbohydrate Amount per 8 ounces (as served) 55 -160 mg 20 -55 mg 11 -19 gm

Acclimatization l Physiologic adaptation that occurs in response to heat exposure in a natural environment ä ä ä l Results: ä ä l 5 days for most 14 days required for 95% of population to have complete acclimatization. Can deacclimatize as quickly sweat at lower temperature increased volume of sweat decrease in amount to salt secreted in sweat increased heat dissipation = lower core body temperature End result: Decreased risk for heat injury!

Fluid Replacement Guidelines for Warm Weather Training

Questions?