Heat Injuries

Objectives Describe physiological factors associated with Heat Injury Describe types of heat injuries Describe prevention of heat injuries

Physiological Factors Illness: Personnel suffering from or recovering from an acute or chronic disease. Previous history: Personnel with prior heat illness. Skin trauma: personnel suffering from sunburn, heat rash, or other dermatologic disorder. Dehydration: Fluid output greater than fluid input. Causes: Nausea, Vomiting, insufficient fluid intake.

Physiological Factors Fatigue: Physical and mental weariness can cause a lack of concern and result in a failure to take proper precautions. Obesity: Fat will interfere with heat regulatory mechanism, cause the individual to expend more energy to accomplish a given amount of work and could be an indicator of poor conditioning.

Obesity!!

Heat Injury Types

Heat Cramps Painful and severe cramps of the voluntary muscles, primarily in the extremities and abdominal wall. Result from the loss of salt through sweating. The body temperature remains normal unless accompanied by heat exhaustion. Treatment: cooling and fluid/electrolyte replacement.

Heat Syncope Occurs when there is excessive pooling of blood in the extremities, consequently the brain down receives enough blood. Peripheral vasodilatation to dissipate the heat and if personnel have been standing still they are likely to faint. Most likely to occur after marching or exercise. Prevent by not having personnel stand in heat after exercising or for excess amounts of time.

Heat Exhaustion Most common form of heat casualty Results from peripheral vascular collapse due to excessive water and salt depletion. Symptoms: Profuse sweating, headache, weakness, pallor, nausea, vomiting, mild dyspnea, and palpitations. May become faint and lose consciousness. May have low blood pressure, body temperature may be elevated or normal and pupils may be dilated.

Heat Exhaustion Treatment: Cooling and fluid replacement, making sure the patient doesn’t go into hypothermia.

Heat Stroke MEDICAL EMERGENCY!! Total collapse of the thermal regulatory mechanism. Symptoms: dizzy, weak, nausea, headache, confusion, disorientation, drowsy, and irate behavior. Skin may be hot and dry or there may be profuse sweating. Loss of consciousness, coma, convulsions may occur.

Heat Stroke Body temperature may reach 40° C – 42.2° C Treatment: Must be immediate. Immediate cooling and evacuation to medical facility. Remove or loosen clothing, move to shaded area, spray or splash with water, rub with ice, fan, take whatever steps to cool the body immediately. Watch the victim for hypothermia. Monitor temperature (rectal). I.V.: Normal saline should be given immediately.

Heat Injury Prevention

Water intake: Single most important factor in prevention! Leaders must enforce water intake Make sure soldiers replace fluids lost through sweating. Urine color is a good indicator of dehydration. The darker the color the more dehydrated the person is. Heat Injury Prevention

Acclimatization: Period of three weeks is optimal for adjustment to new environment, with progressive degrees of heat exposure and physical exertion. Note that acclimatization at one level of heat stress doesn’t guarantee any level of acclimatization at higher levels of heat stress.

Heat Injury Prevention Proper wear of the uniform is essential for adequate protection Must be loose fitting at neck and arms to permit circulation Clothing blocks sun rays from damaging skin When exposed to high heat wearing the least allowable amount of clothing is desirable

Work/Rest Cycles: If outside must be tailored to be at the coolest parts of the day. Work must be curtailed and even suspended under extreme heat conditions. Work/Rest in the shade when possible Ensure members are eating for needed salt replacement Buddy System: Train troops to recognize signs of cold injury to help prevent a buddy from injury Heat Injury Prevention

Review Questions 1.What are some physiological factors that can cause heat injuries? 2.What causes heat cramps? 3.Heat syncope occurs when? 4.List some symptoms of heat exhaustion? 5.What temperature could the body reach if someone is experiencing heat stroke? 6.What is the single most important factor in preventing heat injuries?