Chapter 170

The heatstroke victim can be difficult and challenging, even after a successful resuscitation and stabilization in the Emergency Department. Heatstroke is a multisystem insult. More than 300 people die of heat-related illness in the United States each year.1 This number was surpassed in a single week in 1995 during a heat wave in Chicago.2–6 This heat wave resulted in more than 400 deaths and 3300 Emergency Department visits. Heatstroke is a very uncommon medical emergency and considered by some as the most important of all the environmental heat illnesses because of its potential for high morbidity and mortality. Major complications of heatstroke include seizures, adult respiratory distress syndrome (ARDS), acute renal failure, liver disease, rhabdomyolysis, and disseminated intravascular coagulation.7 Survival is possible for the great majority of patients with appropriate recognition and rapid treatment.

The most effective means of cooling remains controversial. The techniques rely upon prompt recognition of symptoms, immediate intervention in the field, and immediate intervention in the Emergency Department. Begin cooling the patient in the prehospital setting by removing the patient from the heat stress, keeping the skin wet, and fanning the patient in transport. The patient must be exposed adequately and cooling must be initiated in the quickest and most efficient manner possible as stabilization is occurring.

Cooling measures must be modified to avoid hypothermia once the core temperature reaches 39 °C or 102 °F. Decreasing the core body temperature to less than 39 °C or 102 °F within 30 minutes of presentation improves survival.4Cooling must precede investigation for the cause. Evaporation and convection are the simplest and most efficient means of cooling victims of heatstroke or heat exhaustion. Evaporation of 1 g of water dissipates approximately seven times more heat than melting the same quantity of ice.4 Skin blood flow is preserved as compared with the use of ice, because evaporation and convection are much more efficient modes of heat exchange.8

Heat-related illness comprises a spectrum of symptoms ranging from mild heat edema to heatstroke. Heat edema is self-limited. The patient presents with edema of the hands, feet, and ankles. This usually occurs in the first few days of heat acclimatization. Heat cramps occur most often in individuals who sweat profusely and are exercising or walking. The patient consumes water without salt, resulting in hyponatremia and muscle cramps. Heat syncope is dizziness or syncope after exposure to high temperatures. It is caused by vasodilatation and consequent postural hypotension. Heat exhaustion results from the excessive loss of body water, electrolytes, or both. The patient may complain of headache, nausea, vomiting, malaise, and myalgias. Heat exhaustion is distinguished from heatstroke by a normal mental status and, generally, a temperature below 39 °C or 102 °F.2,7

Heatstroke must be suspected in any patient who has acute mental status changes or other signs of central nervous system dysfunction in the setting of a high ...

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