Altitude Sickness

What would happen to you if you were taken immediately to the summit of Mt. Everest? The answer is you would pass out, and likely die within minutes. So how then can people summit Everest without oxygen? The answer to this lies in the understanding of oxygen, pressure, and your body’s ability to acclimate over time. In general, the percent of oxygen in the air stays the same with altitude; however, the partial pressure of the oxygen in the air mixture decreases. Although overly simplistic, this means that as we gain altitude, the molecules of oxygen are more spread out and our bodies’ ventilation systems do not work as well. Over time, our bodies can adapt to lower pressure, therefore someone who is properly acclimated can withstand much higher altitudes than someone who is not.

Acute Mountain Sickness (AMS) is the term used to describe illness related to altitude. Unfortunately, the symptoms of AMS are similar to many other illnesses. Crews and individuals that live at lower elevations (usually below 4,000 feet) and are working and sleeping above 6,500 feet are at risk for AMS. It is rare to experience AMS below 8,000 feet; however, about 50% of people will experience at least a mild form of AMS above 10,000 feet. AMS should be considered if an individual:

1. Recently traveled to a higher elevation (generally above 8,000 feet) AND

2. Has a headache AND

3. Has other symptoms including:

   1. Dizziness or lightheadedness

   2. Fatigue or weakness

   3. Nausea/vomiting/anorexia

   4. Insomnia

The most severe symptoms of altitude sickness arise from edema, or fluid accumulation, in the body. If a person has recently arrived from a lower elevation and is having significant difficulty breathing, significant coughing with blood-tinged spit, confusion, or alterations in their mental status they may have a severe form of AMS.

Prevention of AMS is done by slowly ascending to altitude over several days, working at higher altitudes, and sleeping at lower altitudes, as well as maintaining sufficient nutrition and hydration.

Treatment of AMS depends on the severity. For mild symptoms, rest and hydration and a moderate descent in altitude for one or two days will allow for complete recovery and the ability to continue to work at altitude. Treatment for severe symptoms are immediate descent and evacuation.

Other examples include:

• High altitude cerebral edema (HACE) is a severe and potentially fatal condition associated with high altitude illness that is often thought of as a late or end-stage AMS.

• High altitude pulmonary edema (HAPE) is a severe form of high altitude illness that, if left untreated, can lead to mortality in 50 percent of affected individuals. It occurs secondary to hypoxia and is a form of noncardiogenic pulmonary edema. It is characterized by fatigue, dyspnea, and a dry cough with exertion.

Discussion Questions:

Where are some places you operate or may operate that could put you or your crew at risk for developing AMS?

If you are dispatched to a fire at altitude, what are some steps you could take to minimize the risk of AMS?

References:

CDC High Altitude Travel and Altitude Illness