Heat-Related Emergencies
Heat-related illness exists on a spectrum from mild heat cramps to life-threatening heat stroke. The body normally maintains core temperature through radiation, convection, conduction, and evaporation. When heat production exceeds the body's cooling capacity, heat illness develops. Risk factors include high ambient temperature, high humidity (which impairs evaporative cooling), strenuous activity, dehydration, extremes of age, and certain medications (anticholinergics, diuretics, beta-blockers).
Heat exhaustion presents with heavy sweating, weakness, nausea, headache, dizziness, and tachycardia. The skin is usually cool and clammy. Core temperature may be elevated but typically remains below 104 degrees F (40 degrees C). Treatment includes moving the patient to a cool environment, removing excess clothing, applying cool water to the skin, and encouraging oral hydration if the patient is alert and not nauseated.
Heat stroke is a true medical emergency defined by a core temperature above 104 degrees F with altered mental status. The patient may or may not be sweating; the classic teaching that heat stroke patients have hot, dry skin is unreliable. Other findings include seizures, tachycardia, hypotension, and eventually organ failure. Treatment priorities are rapid cooling (cold water immersion is ideal, but ice packs to the neck, axillae, and groin are effective alternatives) and rapid transport. This condition has a high mortality rate if cooling is delayed.
Hypothermia
Hypothermia is defined as a core temperature below 95 degrees F (35 degrees C). It can develop from cold environmental exposure but also occurs in temperate conditions when patients are wet, intoxicated, malnourished, or have impaired thermoregulation. Mild hypothermia (90 to 95 degrees F) presents with shivering, confusion, and impaired coordination. Moderate hypothermia (82 to 90 degrees F) causes loss of shivering, increasing confusion, and cardiac arrhythmias. Severe hypothermia (below 82 degrees F) may present with fixed dilated pupils, unresponsive appearance, and cardiac arrest.
Management includes gentle handling (rough movement can trigger ventricular fibrillation in a cold heart), removal of wet clothing, passive rewarming (blankets, warm environment), and active external rewarming (warm packs to the trunk). Do not rewarm the extremities first, as this can cause cold blood to rush back to the core. Remember the saying: "A patient is not dead until they are warm and dead." Hypothermic patients in cardiac arrest may respond to resuscitation after rewarming.
Submersion Incidents (Drowning)
Drowning is the process of experiencing respiratory impairment from submersion or immersion in liquid. The key pathophysiology is hypoxia from water aspiration or laryngospasm. Management priorities are removing the patient from the water safely, initiating rescue breathing (even in the water if trained), performing CPR immediately on land, and providing high-flow oxygen. Suspect cervical spine injury in diving accidents and shallow water incidents. All submersion victims require transport and observation, even if they appear asymptomatic initially, because pulmonary edema can develop hours after the event.
Lightning Injuries
Lightning strikes cause approximately 50 deaths annually in the United States. Unlike other electrical injuries, lightning delivers a massive but brief current that often causes cardiac arrest through asystole. Reverse triage applies to lightning strike victims: treat those who appear dead first, as they may be in reversible cardiac arrest, while those who are moving and groaning are likely to survive without immediate intervention. Begin CPR and apply an AED immediately. Other injuries include burns (often superficial, with a characteristic fern-like pattern called Lichtenberg figures), tympanic membrane rupture, and spinal injuries from the blast effect.