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HEAT INJURIES. OBJECTIVES. Risk Factors Types of Heat Injury *symptoms, cause and treatment Pre-hospital care Management. Individual Risk Factors. Poor fitness Large body mass Minor illness Drugs (cold/allergy/blood pressure/performance enhancing) Highly motivated.
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OBJECTIVES • Risk Factors • Types of Heat Injury *symptoms, cause and treatment • Pre-hospital care • Management
Individual Risk Factors • Poor fitness • Large body mass • Minor illness • Drugs (cold/allergy/blood pressure/performance enhancing) • Highly motivated
Types of Heat Injury • Heat Cramps • Heat Exhaustion • Heat Stroke
Heat Cramps • Painful cramping of the larger muscle groups • legs, arms, abdomen • Due to excessive loss of salt through heavy sweating plus several hours of sustained exertion • acclimatization decreases risk • Treatment • 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 plus fluids
Heat Exhaustion • Symptoms: • heavy sweating, headache, light-headed, nausea/vomiting, tingling sensations • Temperature 99-104 F • Cause: • dehydration plus excessive salt depletion • Treatment: • shaded environment; loosen clothing • If suspect early heat stroke, treat as such • oral fluids if can drink • cold water, 0.1% salt solution, or 6% carbohydrate beverage • 1-2 liters over 2-4 hours • EVAC
Heat Stroke • Symptoms: • elevated temperature plus central nervous system disturbance • absence of sweating is a late finding • Can begin as heat exhaustion and progress • End-organ damage: • brain damage, kidney failure, liver failure, blood clotting abnormalities • related to duration of elevated temperature
Treatment of Heat Stroke • ABC • Unconscious patient may vomit and aspirate • Keep patent airway • IV: no more than 2L unless circulatory collapse • Lower the body temperature as fast as possible! • All clothes off • Cool water with fanning...increase evaporation • Ice packs near groin or in the axilla • EVAC...open doors/windows in vehicle • keep cooling to temp 101-102 F.
Risk Factors for Heat Stroke • Dehydration • Respiratory and GI illnesses most common • Alcohol use • Laxatives and diuretics • Medications • Increase heat production and/or decrease heat loss • pseudoephedrine, thyroid hormone, cocaine • Decrease sweating • antihistamines (Benadryl), anti-nausea (Phenergan) • Supplements • Ephedrine (MaHuang), caffeine
Pre-Hospital Care • Cooling is first priority • Offer drink • Drench with water • Fan • Massage large muscles • Stop all measures if shivering occurs
Guidance for Sports Drinks • Cool water is usually the best rehydration fluid • Prolonged training and participation • carbohydrates and electrolytes are also required for optimal physical and mental performance • meals and snacks plus water are best • When sports drinks are appropriate: • 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
Fluid Replacement Guidelines • Easy Activity • 1 QT water per 2 hours • Work:rest as needed • Moderate Activity • 3 QT water per 4 hours • Work:rest 40:20 • Hard Activity • 1 QT per hour • Work:rest 30:30 more rest with increased RF • Do not consume >12 QT per day.
Acclimatization • Physiologic adaptation that occurs in response to heat exposure in a natural environment • 5 days for most • 14 days required for 95% of population to have complete acclimatization. • Can DE acclimatize as quickly • Results: • 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!