Wilderness and Rescue Medicine 8th Edition

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Wilderness and Rescue Medicine

hypoglycemia, dehydration, hypothermia, hyper- thermia, and simple exhaustion. All of these problems can cause a decrease in muscular per- formance and efficiency, and all can cause changes in mental status. Even though your primary con- cern may be altitude, it is important to include all five problems as possible causes until proven otherwise. Severe HACE is treated using all the techniques and medications useful for the mild and moderate forms, plus an immediate descent of at least 1,000 meters. Exertion should be minimized, but there should be no delay in descent. A patient in severe HACE is not likely to survive without aggressive intervention. High-Altitude Pulmonary Edema Unlike HACE, which develops within 24 hours, HAPE tends to develop several days after arrival at altitude. It can exist without any symptoms of HACE or present long after symptoms of HACE have cleared. At moderate altitudes (2,700–4,000 meters), HAPE tends to occur as an isolated illness.

improvement or resolution of symptoms can be noted with as little as 300 meters drop in altitude. Mild HAPE can also be safely managed on site if low-flow supplemental oxygen can be given over 24 hours, and if descent will be easy and quick to accomplish if conditions worsen. Acetazolamide at 125 mg twice a day may also help.

This chest x-ray shows the patchy accumulation of fluid in the alveoli of the right lung that can be heard as crackles with a stethoscope. If pulmonary edema worsens, the patient expe- riences shortness of breath, even at rest, and a persistent cough. Crackles on inspiration are audible with a stethoscope or an ear to the chest. Moderate HAPE is a bad sign. The condition tends to progress from bad to worse. Unfortunately, exertion makes pulmonary ede- ma worse due to an increase in pulmonary hyper- tension. There may be situations where it would be better to remain where you are rather than perform a strenuous evacuation over a mountain pass. If descent will be delayed, supplemental oxygen and positive pressure ventilations can be lifesaving. HAPE also responds to treatment in a portable hyperbaric chamber.

General Principles

High - Altitude Pulmonary Edema Mechanism: • C apillary dilation and leakage leading to pulmonary edema Signs and Symptoms: • Mild – decreased performance, dry cough, mild SOB on exertion

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• Moderate – persistent cough, inspiratory crackles, SOB at rest, low grade fever

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• Severe – respiratory failure, copious sputum, marked crackles

© 2018 WMA

The early symptoms of HAPE are shortness of breath on exertion, general fatigue, and some- times a dry cough. It can also produce a low-grade fever. People with an existing or recent respiratory illness seem to be more predisposed to develop HAPE. In fact, many patients will mistake mild HAPE for a worsening pneumonia or bronchitis. In the early stages, fluid in the alveoli may not be audible with a stethoscope. The ideal treatment for HAPE is supplemen- tal oxygen and immediate descent. Significant