Management

Measurement of core temperature using a rectal thermometer or oesophageal probe in the intubated patient is often necessary.

The core temperature may lag behind and remain elevated despite the superficial temperature (axillary/tympanic) being below 40°C.

Management includes:

Cooling techniques

There are a number of ways to cool the hot patient.

Spraying the patient with tepid water and using a fan is the most practical method. Immersing the patient’s limbs or whole body in cool water is described but impractical.

Simple adjuncts to cooling, such as the use of cooled peripheral intravenous fluids and placing of icepacks in the groin and axillae, are often used. Care must be taken with ice packs as prolonged skin contact may cause tissue damage. Cold fluid peritoneal and gastric lavage and cardiopulmonary bypass have also been described, but are not usually necessary.

The aim of cooling is not to achieve rapid normothermia as this would result in overshoot hypothermia. The target core temperature when cooling should be 38.5°C. Once this temperature is reached, active cooling measures are stopped. Rebound hyperthermia may occur after active cooling is stopped [6].

Shivering can occur during active cooling. This can act to reduce the rate of cooling as shivering generates heat. Benzodiazepines reduce shivering, make cooling techniques more tolerable, and are used to treat seizures. Dantrolene should not be used to treat environmental heat-related illness.

Supportive care

All patients require fluid replacement alongside active cooling.

Hypotension can be difficult to manage in heat stroke. Patients are often dehydrated, vasodilated and in renal failure.

Although fluid is required to restore intravascular volume, aggressive fluid resuscitation may be harmful.

Central venous pressure measurement and urinary catheterisation should be established early in all patients with heat stroke. If hypotension persists despite fluid resuscitation, cooling vasopressors may be needed.

Seizures should be treated with intravenous benzodiazepines.

Patients need intensive care management, with the following considerations:

• Renal failure may require haemofiltration
• Hepatic damage can be extensive
• Liver transplantation has been required

Learning bite

Management of heat stroke involves active cooling, intravenous fluids, invasive monitoring and full supportive care in an ICU setting.