HEAT INJURIESHEAT INJURIES

OBJECTIVESOBJECTIVES

Risk Factors

Types of Heat Injury

*symptoms, cause and treatment Pre-hospital care

Management

Individual Risk FactorsIndividual Risk Factors

Poor fitness Large body mass Minor illness Drugs (cold/allergy/blood

pressure/performance enhancing) Highly motivated

Types of Heat InjuryTypes of Heat Injury

Heat Cramps

Heat Exhaustion

Heat Stroke

Heat CrampsHeat 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 ExhaustionHeat 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 StrokeHeat 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 StrokeTreatment 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 StrokeRisk 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 CarePre-Hospital Care

Cooling is first priority Offer drink Drench with water Fan Massage large muscles Stop all measures if shivering occurs

Guidance for Sports DrinksGuidance 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 GuidelinesFluid 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.

AcclimatizationAcclimatization 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!

Fluid Replacement for Warm Weather Fluid Replacement for Warm Weather

Heat Category

WBGT Index, °F

Easy Work Moderate Work Hard Work

Work /Rest

Water Intake,Qt/

h

Work /Rest

Water Intake,

Qt/h

Work /Rest

Water Intake,

Qt/h 1 78-81.9 NL ½ NL ¾ 40/20 min ¾ 2

(Green) 82-84.9 NL ½ 50/10 min ¾ 30/30 min 1

3 (Yellow

85-87.9 NL ¾ 40/20 min ¾ 30/30 min 1

4 (Red)

88-89.9 NL ¾ 30/30 min ¾ 20/40 min 1

5 (Black)

> 90 50/10 min 1 20/40 min 1 10/50 min 1

The work/rest times and fluid replacement volumes will sustain performance and hydration for at least 4 hours of

work in the specified heat category. Individual water needs will vary ± ¼ quart/hour. NL = no limit to work time per hour. Rest means minimal physical activity (sitting or standing) and should be accomplished in shade if possible.

Caution: Hourly fluid intake should not exceed 1½ quarts. Daily fluid intake should not exceed 12 quarts.

The EndThe End