INTRODUCTION

Few expeditions in modern times are prepared to go to the lengths of an earlier era when it comes to self-rescue. With satellite phones, GPS positioning, and modern air transport, it is unlikely that any major expedition to any area on earth, no matter how remote, will ever again be as isolated as famous expeditions of the past. The epic survival stories, such as that of Ernest Shackleton and his stranded Endurance crew in Antarctica, are largely the stuff of history. However, even today, ships still sink with all hands on board, and climbers still are lost and their bodies never recovered.

Expeditions have limited resources for treating threats to life and limb. Prevention of injury and illness is therefore extremely important on expeditions. For example, it is better to ascend slowly to high altitudes than to rush up a mountain and be forced to treat expedition members with high-altitude illness. If proper prevention measures fail, however, then the expedition physician must be prepared to deal with untoward events.

It is in the spirit of preparation for untoward events that this chapter on expedition self-rescue is written. Some of the measures taken in advance will complement self-rescue planning. These include provision of communications gear, such as satellite phones and external rescue plans. Other measures, such as including expedition members with search and rescue experience, selfrescue experience, and medical skills and bringing along rescue and medical equipment may enhance the ability of an expedition to perform a self-rescue and evacuation of ill or injured patients.

Scope of the problem

In the US from 1979 to 1995, heat stroke was the stated cause of death in nearly 400 people each year. However, 10 times that number of elderly patients with underlying cardiopulmonary disease are thought to die annually from heat-related complications.

The two major heat illnesses are heat exhaustion and heat stroke.

• Heat exhaustion is a syndrome characterized by volume depletion. The core temperature is generally <40.5°C. Mental status is normal.

• Heat stroke is a medical emergency characterized by a core temperature >40.5°C and altered mental status.

A number of minor heat illnesses have also been described, including heat cramps, heat edema, heat syncope, heat tetany, and prickly heat. Malignant hyperthermia is characterized by very high core temperature and altered mental status, but is not considered an environmental illness.

• Heat cramps are painful muscle cramps which generally occur after exercise in unacclimatized individuals who sweat freely and replace sweat losses with large amounts of water or other hypotonic fluids. Hyponatremia may also occur in this scenario.

• Heat edema is a benign condition, most often found in the elderly, in which swelling occurs in the feet and sometimes the hands during the first few days in a hot environment.

• Heat syncope is a self-limited condition usually found in unacclimatized persons. Prolonged standing causes venous pooling in the legs which, combined with peripheral vasodilation and volume loss, causes orthostatic hypotension and fainting.

• Heat tetany is caused by hyperventilation after brief exposure to intense heat.

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