Download Combat Casualty Care - California Cadet Corps

HEAT INJURIES
Types of Heat Injury

Heat Cramps

Heat Exhaustion

Heat Stroke
Heat Cramps

Painful cramping of the larger muscle groups


Due to excessive loss of salt through heavy
sweating plus several hours of sustained exertion
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
legs, arms, abdomen
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
Heat Exhaustion

Symptoms:



Cause:
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
heavy sweating, headache, light-headed,
nausea/vomiting, tingling sensations
Temperature 99-104 F
dehydration plus excessive salt depletion
Treatment:



shaded environment; loosen clothing
If suspect early heat stroke, treat as such
oral fluids if can drink

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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
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
Lower the body temperature as fast as possible!

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
Unconscious patient may vomit and aspirate
IV: no more than 2L 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


USASOC and TB MED do not recommend
Wilderness Medicine, 3rd ed. supports
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


Decrease sweating


pseudoephedrine, thyroid hormone, cocaine
antihistamines (Benadryl), anti-nausea (meclazine, phenergan)
Supplements

Ephedrine (MaHuang), caffeine
Control Measures

Water and sports drinks

Salt

Acclimatization
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
Sports Drink
Recommendations
INGREDIENT
Sodium
Potassium
Carbohydrate
Amount per 8 ounces (as served)
55-160 mg
20-55 mg
11-19 gm
Acclimatization

Physiologic adaptation that occurs in response to
heat exposure in a natural environment
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Results:
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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
(Average Acclimated Soldier Wearing BDU, Hot Weather)
Heat
Category
WBGT
Index, °F
Easy Work
Work
/Rest
1
2
(Green)
3
(Yellow
4
(Red)
5
(Black)



Moderate Work
Work
/Rest
Hard Work
78-81.9
82-84.9
NL
NL
Water
Intake,Qt/
h
½
½
NL
50/10 min
Water
Intake,
Qt/h
¾
¾
Work
/Rest
40/20 min
30/30 min
Water
Intake,
Qt/h
¾
1
85-87.9
NL
¾
40/20 min
¾
30/30 min
1
88-89.9
NL
¾
30/30 min
¾
20/40 min
1
> 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.


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Wearing body armor add 5°F to WBGT Index.
Wearing MOPP overgarment add 10°F 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 Loose Sand at 2.5 mph, No Load
• Walking Hard Surface at 3.5 mph,
• Walking Hard Surface at 2.5
• Walking Hard Surface at 3.5 mph, <40 lb
>40 lb Load
mph, <30 lb Load
Load
• Manual of Arms
• Calisthenics
• Walking Loose Sand at 2.5 mph
• Marksmanship Training
• Patrolling
with Load
• Drill and Ceremony
• Individual Movement Techniques, i.e. low
crawl, high crawl
• Defensive Position Construction
• Field Assaults
Questions?