Prevention of Heat Injury
By Roland J. Larrabee, M.D.
Summer heat waves cause thousands of cases of heat-related illness in the U.S. each year and hundreds of heat-related deaths, especially among the elderly. Chronically ill, elderly, poor and socially isolated persons without air conditioning are particularly susceptible to heat injury. Those with a previous history of heat-related illness are also at more risk.
The risk of injury rises with increasing temperature, humidity and sun exposure. The most important mechanism for losing heat during activity is evaporation of sweat; when the relative humidity increases, less sweat evaporates. Too much clothing, particularly dark, heavy, impermeable clothing, also decreases evaporation of sweat.
The first symptoms and signs of heat injury include faintness, nausea, vomiting, sometimes diarrhea, headache, gooseflesh on the chest and upper arms, over breathing, muscle cramps and an unsteady gait. Abrupt mental disturbances ranging from garbled speech to deep unconsciousness can occur.
“Heat stroke” usually refers to body temperatures higher than 1050 F and severe mental disturbances, such as delirium or coma. Other potentially fatal complications of heat injury include convulsions, heart attack, and other internal organ damage (e.g., kidney and liver failure).
Infants of children left in closed automobiles can develop fatal heat stroke in 30 minutes or less. Elderly or mentally ill patients may not be thirsty despite becoming dehydrated and should be encouraged to maintain adequate fluid intake. People engaged in strenuous exercise in hot weather should drink water more frequently than thirst dictates.
Many drugs place patients at increased risk of heat injury. Consult your physician to determine if you should take any special precautions during hot weather because of the medications you are taking.
Heat injury can be treated successfully if cooling measures are begun early. Less severe symptoms (“heat exhaustion”) can be treated with drinking extra fluids and by sprinkling water over the patient and fanning to enhance evaporation, or by applying ice packs to the head, neck, abdomen, armpit and groin. Treatment of more severe heat injury is a medical emergency, and one should seek urgent medical attention.
Dr. Larrabee is Associate Director of Family and Community Medicine at the Walter L. Aument Family Health Center, 317 S. Chestnut St., Quarryville.
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