Heat-related emergencies include heat cramps, exhaustion and stroke. These emergencies are the No. 1 weather-related killer and claim more lives than hurricanes, tornadoes, flooding and lightning combined. Prolonged exposure to high temperatures and excessive humidity are the primary culprits.

The elderly and the chronically ill are high-risk populations. Impaired thermoregulation, blunted thirst mechanisms, underlying medical conditions and medication interactions are a few reasons. Diuretics, beta-blockers, antihistamines and antidepressants can compromise a patient.

Heat stroke is the direst of these emergencies. This occurs when the body’s hypothalamic temperature regulation is lost, causing uncompensated hyperthermia. Heat stroke is characterized by a body temperature of 104 degrees Fahrenheit or higher and central nervous system impairment. The neurological findings include confusion, slurred speech, agitation, seizures and unconsciousness. Skin findings include diaphoresis or hot/dry conditions. The brain, liver, kidneys and muscles can be damaged.

Cold water immersion

Cold water immersion (CWI) is a simple and proven therapy for heat stroke. The American Heart Association recommends CWI over traditional methods.

When CWI is administered, a patient is placed in a heavy-duty PVC bag, which has numerous handles and drainage valves. Water and ice are added into the bag, and the patient’s body temperature quickly decreases. (Cool water removes heat 25 times faster than air does.) Traditional therapies, such as cold packs and water dousing, with fanning, aren’t nearly as effective as and cool more slowly than CWI.

Steps for CWI

• Confirm heat stroke (hot environment, altered mental status, high body temperature).
• Request or find ice (ice is fairly available).
• Remove unneeded clothing from the patient.
• Attach monitoring devices (ECG electrodes/pads, pulse oximetry, capnography).
• Place the patient into the CWI bag; always keep the head and airway visible.
• Fill the bag with two inches of cool water.
• Add the ice when it becomes available.
• Agitate the ice/water often.
• Transport to and notify the receiving hospital.
• Monitor the patient’s temperature, ECG, pulse, blood pressure, respirations, SpO2 and capnography); discontinue the therapy if the patient becomes conscious or the patient’s temperature drops below 102 degrees F.
• Once at the hospital, empty water from the CWI bag.
• For shivering or seizures, consider midazolam. For nausea and vomiting, consider ondansetron.

Tips

Ice packs placed in the axilla and groin and on the neck and cool water application with fanning can be used temporarily, but CWI is the priority.

Remember, heat loss is much more immediate when a patient is immersed in chilled water.

Fire apparatus water shouldn’t be used. This water can be very warm.
CWI should be used only for confirmed heat stroke patients, not for suspected sepsis.

Complications

The most common complication that’s associated with CWI is hypothermia from a temperature-reduction overshoot: The therapy is overly effective, and the core temperature drops precipitously. In EMS systems that have longer transports, the patient is cooled and removed from the bag before transport to avoid this. Regular temperature monitoring is needed when the patient is in the bag.

Heat stroke complications include poor oxygenation and ventilation. This can be managed with traditional ABC therapies. Hypovolemia and hypotension can be managed initially with fluids.