9 Rfr Heat Injuries

7/28/2019 9 Rfr Heat Injuries

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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 > 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

S i


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Sports Drink

Recommendations

INGREDIENT Amount per 8 ounces (as served)

Sodium 55-160 mg

Potassium 20-55 mgCarbohydrate 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(Average Acclimated Soldier Wearing BDU, Hot Weather)

HeatCategory

WBGTIndex, F Easy Work Moderate Work Hard Work

Work/Rest

WaterIntake,Qt/

h

Work/Rest

WaterIntake,

Qt/h

Work/Rest

WaterIntake,

Qt/h

1 78-81.9 NL NL 40/20 min

2(Green)

82-84.9 NL 50/10 min 30/30 min 1

3(Yellow

85-87.9 NL 40/20 min 30/30 min 1

4(Red)

88-89.9 NL 30/30 min 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 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 1 quarts.

Daily fluid intake should not exceed 12 quarts. Wearing body armor add 5F to WBGT Index. Wearing MOPP overgarment add 10F to WBGT Index. An acclimitized soldier is one who has worked in the given heat conditions for 10-14 days Examples:

Easy Work Moderate Work Hard Work

Weapon Maintenance Walking Hard Surface at 2.5mph,


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Questions?


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Documents

9 Rfr Heat Injuries