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Altitude Awareness 1-800-295-4820 |
ALTITUDE AWARENESS
When traveling to higher elevations than you may be used to, there is a certain amount of risk involved. There are certain illnesses brought on by changes in elevation and this is definitely something worth paying attention to. There are no specific factors such as age, sex, or physical condition which correlate with susceptibility to altitude sickness, so another words, some people get it and some people don’t. If you haven’t been to high altitudes before, it is important to be cautious.
What causes Altitude Illness? “The concentration of oxygen at sea level is about 21% and the barometric pressure averages 760 mmHg. As altitude increases, the concentration remains the same but he number of oxygen molecules per breath is reduced. At 12,000 feet (3,658 meters) the barometric pressure is only 483 mmHg, so there are roughly 40% fewer oxygen molecules per breath. In order to properly oxygenate the body, your breathing rate (even while at rest) has to increase. This extra ventilation increases the oxygen content in the blood, but not to sea level concentrations. Since he amount of oxygen required for activity is the same, the body must adjust to having less oxygen. In addition, for reasons not entirely understood, high altitude and lower air pressure causes fluid to leak from the capillaries, which can cause fluid build-up in both the lungs and the brain. Continuing to higher altitudes without proper acclimatization can lead to potentially serious, even life-threatening illnesses.”
What is Acclimatization? “The major cause of altitude illnesses is going too high too fast. Given time, our body can adapt to the decrease in oxygen molecules at a specific altitude. This process is known as acclimatization and generally takes 1-3 days at that altitude. For example, if you hike to 10,000 feet (3,048 meters), and spend several days at that altitude, you body acclimatizes to 10,000 feet (3,048 meters). If you climb to 12,000 feet (3,658 meters), your body has to acclimatize once again. A number of changes take place in the body to allow it to operate with decreased oxygen.
How do I prevent Altitude Illness? “Prevention of altitude illnesses falls into two categories, proper acclimatization and preventive medications. Below are a few basic guidelines for proper acclimatization.
Preventive Medications: “Diamox (Acetazolamide) allows you to breathe faster so that you metabolize more oxygen, thereby minimizing the symptoms caused by poor oxygenation. This is especially helpful at night when respiratory drive is decreased. Since it takes a while for Diamox to have an effect, it is advisable to start taking it 24 hours before you go to altitude and continue for at least five days at higher altitude. The recommendation of the Himalayan Rescue Association Medical Clinic is 125 mg. twice a day (morning and night). (The standard dose was 250mg., but their research showed no difference for most people with the lower dose, although some individuals may need 250mg.) Dexamethasone (a steroid) is a prescription drug that decreases brain and other swelling reversing the effects of AMS. Dosage is typically 4 mg twice a day for a few days starting with the ascent. This prevents most symptoms of altitude illness. It should be used with caution and only on the advice of a physician because of possible serous side effects. It may be combined with Diamox. No other medications have been proven valuable for preventing AMS.”
What is AMS? Acute Mountain Sickness (AMS) “is common at high altitudes. At elevations over 10,000 feet (3048 meters), 75% of people will have mild symptoms. The occurrence of AMS is dependent upon the elevation, the rate of ascent, and individual susceptibility. Many people will experience mild AMS during the acclimatization process. Symptoms usually start 12-254 hours after arrival at altitude and begin to decrease in severity about the third day. The symptoms of Mild AMS re headache, dizziness, fatigue, shortness of breath, loss of appetite, nausea, disturbed sleep, and a general feeling of malaise. Symptoms tend to be worse at night and when respiratory drive is decreased. Mild AMS does not interfere with normal activity and symptoms generally subside within 2-4 days as the body acclimatizes. As long as symptoms are mild, and only a nuisance, ascent can continue at a moderate rate. When hiking, it is essential that you communicate any symptoms of illness immediately to others on your trip. AMS is considered to be a neurological problem caused by changes in the central nervous system. It is basically a mild form of High Altitude Cerebral Edema (see below).”
Basic Treatment of AMS The only cure is either acclimatization or descent. Symptoms of Mild AMS can be treated with pain medications for headache and Diamox. Both help to reduce the severity of the symptoms, but remember, reducing the symptoms is not curing the problem. Diamox has been known to cause severe allergic reactions to people with no previous history of diamox or sulfa allergies.
Moderate AMS Moderate AMS includes severe headache that is not relieved by medication, nausea and vomiting, increasing weakness and fatigue, shortness of breath, and decreased coordination (ataxia). Normal activity is difficult, although the person may still be able to walk on their own. At this stage, only advanced medications or descent can reverse the problem. Descending even a few hundred feet (70-100 meters) may help and definite improvement will be seen in descents of 1,000-2,000 feet (305-610 meters). Twenty-four hours at the lower altitude will result in significant improvements. The person should remain at lower altitude until symptoms have subsided (up to 3 days). At this point, the person has become acclimatized to that altitude and can begin ascending again. The best test for moderate AMS is to have the person “walk a straight line” heel to toe. Just like a sobriety test, a person with ataxia will be unable to walk a straight line. This is a clear indication that immediate descent is required. It is important to get he person to descend before the ataxia reaches the point where they cannot walk on their own (which would necessitate a litter evacuation).”
Severe AMS Severe AMS presents as an increase in the severity often aforementioned symptoms, including shortness of breath at rest, inability to walk, decreasing mental status, and fluid buildup in the lung. Severe AMS requires immediate descent to lower altitude (2,000-4,000 feet [610-1,220 meters]).
Other Medications for Altitude Illness
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