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. Although heatstroke is an uncommon medical emergency, it is considered one of the most important of all the environmental heat illnesses because of its potential for high morbidity and mortality in large numbers.7 Major complications of heatstroke include seizures, adult respiratory distress syndrome (ARDS), acute renal failure, liver disease, rhabdomyolysis, disseminated intravascular coagulation, and death.8 Survival is possible for the great majority of patients with rapid recognition and aggressive management.
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 their 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.4 Cooling must precede the 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.9
The information in this chapter primarily pertains to hyperthermia from heat-related illness. Despite this, some of these techniques may be used for other causes of hyperthermia. These include endocrine disorders, head injury, infection, intracranial hemorrhage, malignant hyperthermia, neuroleptic malignant syndrome, sepsis, serotonin syndrome, stroke, toxins, or other causes. Consider discussing the use of these techniques to treat hyperthermia with the appropriate consultant if the etiology is not heat-related.
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 ...