HEAT%20INJURIES

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HEAT INJURIES
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Types of Heat Injury

• Heat Cramps
• Heat Exhaustion
• Heat Stroke

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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 (MRE) plus
  fluid

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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

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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

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Treatment of Heat Stroke

• ABC
• Unconscious patient may vomit and aspirate
• 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 under groin or axilla
• EVAC...open doors/windows in helicopter/vehicle
• keep cooling to temp 101-102 F.
• Ice-water immersion controversial
• USASOC and TB MED do not recommend
• Wilderness Medicine, 3rd ed. supports

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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
  (meclazine, phenergan)
• Supplements
• Ephedrine (MaHuang), caffeine

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Control Measures

• Water and sports drinks
• Salt
• Acclimatization

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OTSG Guidance for the Field Use of Sports Drinks

• Cool water is usually the best rehydration fluid
• Prolonged training and operational scenarios
• 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 gt 6 hours, hot weather, if snacks/meals
  not consumed
• duration gt 3 hours, strenuous exercise, if
  snacks, meals not consumed
• duration gt 6 hours strenuous exercise, if total
  food intake is significantly limited

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Sports Drink Recommendations

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

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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 deacclimatize 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!

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Fluid Replacement Guidelines for Warm Weather
Training
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Questions?