Heat Injury

Treat a Casualty with a Heat Injury

INTRODUCTION

Heat injuries are environmental injuries that may result when a soldier is exposed to extreme heat. Prevention also depends on proper clothing and appropriate activity levels. Soldiers’ conditions may also be affected and compromised in specific environments due to the protective equipment and gear worn to shield them from contamination during an attack. Identification of high-risk personnel (basic trainees, troops with previous history of heat injury, and overweight soldiers) helps both leaders and individuals prevent and cope with climatic conditions. Instruction on living and working in a hot climate also contributes toward prevention. Acclimatization and protection from undue heat exposure are also very important.

Recognize an environmental emergency

Environmental Emergency - a medical condition caused or exacerbated by the weather, terrain, atmospheric pressure, or other local factors

(1) Instances of environmental emergencies

(2) Environmental impact on morbidity and mortality

(3) Environmental factors that induce or exacerbate other medical or traumatic conditions

Risk Factors

(1) Age

(2) General health

(3) Fatigue

(4) Predisposing medical conditions

(5) Medications

Environmental Factors

(1) Climate

(2) Season

(3) Weather

(4) Atmospheric (barometric) pressure - the pressure exerted by the weight of the air. An increase in altitude decreases pressure.

(5) Terrain

Types of Environmental Injuries

(1) Cold injury

(2) Heat injuries

(a) Heat Cramps

(b) Heat Exhaustion

(3) Localized injuries

(a) Radiation burns, e.g., sunburn

Identifying and manage heat injuries

Heat cramps

A muscle cramp or spasm of the voluntary muscles of the arm, leg, or abdomen caused by depletion in the body of water and salt.

(1) Symptoms

(a) Painful spasms of skeletal muscles including muscles of the extremities (arms and legs) and abdomen

(b) Thirst

(d) Core temperature is normal or minimally elevated

(e) DO NOT ELIMINATE HEAT EXHAUSTION AS A POSSIBILITY. Heat cramps and heat exhaustion may co-exist.

(2) Treatment

(a) Move casualty to shade

(b) Loosen clothing

(d) Oral hydration with electrolyte solution. If nauseated, IV hydration with 0.9% Normal Saline

(e) Obtain further medical advice if symptoms continue

Heat exhaustion

A systemic reaction to prolonged heat exposure and is due to sodium depletion and dehydration

(1) Symptoms

(a) Profuse sweating with pale, moist, and cool skin

(b) Headache

(d) Dizziness

(e) Loss of appetite

(6) Nausea (with or without vomiting)

(f) Confusion

(g) Core temperature may be normal or elevated

(2) Treatment

(a) Move the casualty to a cool shady area

(b) Loosen or remove the casualty's clothing and boots

(d) IV hydration with 0.9% Normal Saline solution preferred

(e) Keep casualty supine

(f) Monitor the casualty and always evacuate - may be heated at BAS and RTD if combat situation dictates

Heatstroke

Caused by failure of the temperature regulating system in the brain.

Heatstroke usually involves excessive exposure to strenuous physical activity under hot conditions.

Elderly or chronically ill patients may develop heatstroke without strenuous physical activity.

The hallmark of this condition is altered mental status.

(1) Symptoms

(a) Sweat may or may not be present

(b) Skin is red (flushed), hot

(d) Dizziness

(e) Nausea

(f) Confusion

(g) Weakness

(h) Seizures

(i) May progress to coma

(j) Respiration and pulse may be rapid and weak

(k) Core temperature is above 104 F

(l) Heatstroke is a medical emergency that will result in death if treatment is delayed

(2) Treatment

(a) Act quickly to prevent further injury

(b) Remove from environment

(i) Remove clothing

(ii) Misting with water and fanning

(iii) Moist wraps

(iv) Immersion in cool water. Do not lower core temperature below 102 degrees. Temperature will continue to drop after removing from water.

(v) Ice packs-groin, axilla

(d) Fluid therapy - IV hydration with 0.9% Normal Saline (if unable to tolerate oral fluids)

(e) Heatstroke is a medical emergency that will result in death if treatment is delayed. Start cooling measures immediately and continue them while waiting for transportation and during evacuation.

Sunburn

(1) Significance

(a) May require hospitalization

(b) Increase risk for further injuries

(d) Usually preventable

(2) Prevention

(a) Limit exposure

(b) Cover skin

(d) Be aware of potential medication reactions

Salt tablets are not used in the prevention of heat injury. Usually eating field rations or liberal salting of the garrison diet will provide enough salt to replace what is lost through sweating in hot weather.

Watch a heat injury casualty closely for life-threatening conditions, check for other injuries, and seek medical aid.

Heat Illness

The inability to respond (increase in core body temperature) adequately to environmental conditions, inadequate correction of fluid and electrolyte deficiencies, and malfunctions of the system through exogenous and endogenous causes

Heat Stress

A condition that increases the metabolism due to heat which may result in an increase of core temp, perspiration, and cardiac output and result in heat injuries if untreated

General assessment and prevention of heat illness

Heat injury assessment

(1) General assessment findings

(a) VITAL SIGNS - continually reassess

(i) Core body temperature (rectal)

(ii) Blood pressure

(iii) Pulse

(b) Nausea, vomiting, diarrhea

(i) Moist?

(ii) Dry?

(iii) Cool?

(iv) Hot?

(d) Mental status assessment

(2) Predisposing factors

(a) Age: pediatric and geriatric-high risk - extremes of age

(b) General health and medications

(i) Cardiac disease

(ii) Diabetes

* Autonomic neuropathy interferes with vasodilation and perspiration

* Autonomic neuropathy may interfere with thermoregulatory input

(iii) Obesity

(iv) Recent illness

(v) Fatigue

(i) Atropine

(ii) Antihistamines

(iii) Tranquilizers

(iv) Cold medications

(v) Antidiuretics

(d) Acclimatization

(e) Length of exposure

(f) Intensity of exposure

(g) Environment

(i) Humidity

(ii) Wind - wind chill

(iii) Ambient air temperature

(h) Alcohol intake within 24 hours

(i) Food consumption

(j) Fever

(k) Clothing, especially NBC gear

(i) The wet bulb globe thermometer (WBGT) index is used to determine the heat condition

(ii) Use of MOPP gear increases the WBGT by about 10 degrees

MOPP Gear

In an environment which protective gear or MOPP gear is worn, heat stress is an important factor to consider.

In environments with moderate and relatively comfortable temperatures, MOPP gear can greatly increase temperatures to the most severe and debilitating level of heat stress.

Therefore, it is important that soldiers in MOPP gear maintain adequate water consumptions, are frequently rotated to reduce occurrence of heat injuries, and establish appropriate rest and work periods to ensure adequate manpower is available.

Water consumption - recommendations:

(1) Follow recommendations on heat category chart

(2) "When" is as important as "how much"

Heat injury prevention

(1) Recommendations

(a) Follow work/rest guidelines on heat category chart

(b) Restrict or modify strenuous physical activities during high heat stress conditions - if combat situation permits

(d) Hold formations in the shade or off blacktop and concrete surfaces whenever possible

(2) Acclimatization

(a) Allow two weeks for soldiers to become acclimated to the heat

(b) Progressively increase the workload during the second week

(3) Cumulative effect

(a) Heat effects build up during the day and over several days

(b) Recovery is slow even after temperatures have decreased

(4) Prevention

(a) Do heavy work early in the day

(b) Follow the highest heat category reached for the remainder of the day

(d) Verify heat injury reporting procedures

(e) Early awareness

SUMMARY

The main points related to these procedures are the following:

(1) The identifying signs and symptoms and prevention of heat injuries

(a) Heat cramps

(b) Heat exhaustion

(2) Procedures for treating heat injuries

(a) Heat cramps

(b) Heat exhaustion