Saturday, July 29

How's the air up there?

By Roberto Moreno M.D.

"Abrupt exposure to high altitude can lead to illness and death. This lesson was tragically learned in 1875 when, while exploring altitudes over 25,000 ft. in their hot air balloon, two of three scientists suddenly died. Recently, the 1996 catastrophe on Mt. Everest, where 12 climbers lost their lives in a single night, shocked the world and opened the eyes of many to the sport of mountaineering and the effects of high altitude on the human body. Although the majority of those who read Jon Krakauers Into Thin Air and other climbing books will do nothing more adventurous than walk their dog in the park, others will be challenged by the high mountains and will attempt to reach extreme elevations. Unfortunately, many will lack proper knowledge of the detrimental effects of altitude, the greatest limiting condition on any climb.

The most common form of altitude illness is called Acute Mountain Sickness (AMS). This is commonly just a mild to moderate discomfort, which usually resolves on its own. High Altitude Pulmonary Edema (HAPE) and High Altitude Cerebral Edema (HACE) are severe, life threatening diseases that must be treated immediately. The degree of altitude and the rate of ascent are the most important contributing factors in all altitude illnesses.

Illumination Saddle, Mt. Hood, Oregon - 11,000 ft.

Definicion De La Altitud (definition of altitude)

High Altitude - 9,000 to 14,000 ft. Very few people will have symptoms below this level. Rapid ascent to this altitude without acclimatization, will cause more than half of all climbers to have mild to moderate AMS symptoms. A few people will suffer severe mountain illnesses.

Very High Altitude - 14,000 to 18,000 ft. Most altitude related fatalities occur at this level. A too rapid ascent to this elevation will result in a high incidence of severe medical problems.

Extreme Altitude - above 18,000 ft. Effects on the body are severe at these elevations even with proper acclimatization. Altitude illnesses are less of a hazard than falls, avalanches, hypothermia and frostbite. Above 18,000 ft., prolonged stays result in mental and physical deterioration, not acclimatization.

La Enfermedad De Las Montanas Aguda (acute mountain sickness)

A headache in the presence of a recent increase in altitude and at least one other of the following symptoms indicates AMS; lack of appetite, nausea, weakness, dizziness, or difficulty breathing at rest. AMS usually takes 8 to 24 hours to develop and, in its early stages, it feels exactly like a hangover. AMS occurs equally between men and women and superb physical conditioning doesnt protect anyone from it. Someone who has had AMS in the past is more likely to experience it again in the presence of high altitude.

The etiology of AMS is most likely from blood vessels in the brain dilating, which causes a headache. As we gain altitude from sea level, the concentration of oxygen in the air progressively gets lower. The body compensates for this lower level of oxygen by breathing faster and increasing blood flow to the brain, by dilating blood vessels, so they can deliver more oxygen. Treatment includes rest, plenty of fluids (at least 3 liters a day), complex carbohydrates, and Ibuprofen or Tylenol. Once the symptoms are over, the climber can ascend safely. However, if the symptoms are ignored, AMS can progress to HAPE.

A. Normal chest x-ray / B. A person with high altitude pulmonary edema--all the white patchy things are abnormal fluid in the lung.

Edema Pulmonar De La Altitud Alta (high altitude pulmonary edema)

HAPE is a life threatening disorder of the lungs, that occurs when fluid from the blood vessels that carry blood from the heart to the lungs become damaged. It allows blood to escape into the spaces in the lung, which are essential for oxygen to be exchanged from the air. The more space occupied by blood, the less oxygen will be available for the body. Breathing then becomes difficult as the oxygen levels in the body drop.

Symptoms usually begin 24 to 72 hours after a too rapid ascent to altitudes above 10,000 ft. and they are most common in individuals who immediately engage in heavy physical exercise, or those who recently have had bad colds or the flu. Signs of HAPE usually consist of shortness of breath, cough and fatigue. As the symptoms progress, coughing can become severe, with blood tinged spit and sometimes gurgling can be heard in the lungs. When oxygen levels drop, hallucinations and unconsciousness may occur. Treatment must include evacuation to lower altitudes and oxygen administration. It is imperative that the person is kept warm, as cold can cause the blood vessels to push more blood into the air spaces in the lungs.

Edema Cerebral De La Altitud Alta (high altitude cerebral edema)

A severe form of AMS that is manifested by headache, loss of coordination, weakness, hallucinations, irrational behavior and unconsciousness in the setting of a recent increase in altitude is termed HACE. It generally occurs at higher altitudes than pulmonary edema (greater than 13,000 ft.) and is less common (incidence of about 1% compared to 5%). If resting, aspirin or Tylenol cannot relieve a severe headache, then HACE should always be suspected.

The average duration of exposure before development of cerebral edema is five days. It is caused by an extreme increase in blood flow to the brain, to the degree that it damages brain tissue cells and swelling of the brain results. This is life threatening and the only treatment is early recognition and immediate descent to lower altitude. Supplemental oxygen, steroids and maintaining a sitting or standing position (which all decrease blood flow to the head) may help diminish the amount of swelling. People who have suffered from HACE should refrain from ever ascending to high altitudes again.

The A Hiplano in Bolivia with 20,000 ft. peaks in the background

Prevencion De La Enfermedades De Las Montanas (prevention of mountain illnesses)

The only preventive treatment is appropriate acclimatization. There is great individual variation in altitude tolerance and, as of now, there is no medical test that can identify how a person will acclimate. It is also impossible to determine once at altitude, when a person is fully acclimated. Practical advice would dictate that once above 10,000 ft., several days rest is needed before ascending higher, with no more than 2,000 ft. gain per night of sleeping elevation. The altitude at which the party sleeps is a more important factor than the elevation attained that day. Diamox (acetazolamide), 125  250 mg. every 12 hours, can help prevent and minimize both AMS and HAPE. It works by diminishing the headache and increasing breathing rate, but it is a diuretic with some nagging side effects (tingling in the fingers and toes). The duration of benefit is usually less than a week and should never be a substitute for proper acclimatization. Most physicians agree that Diamox should only be used for treatment in persons who have AMS or HAPE, or for prophylaxis for those who have had it in the past. Nifedipine has also proven to be helpful in preventing HAPE.

Las Reglas Mas Fuertes De Las Enfermedades De La Altitud (the golden rules of altitude illness)
Any illness at altitude is an altitude-related illness until proven otherwise. Never ascend with the symptoms of AMS. If AMS is getting worse or if HAPE or HACE are suspected, BAJA, BAJA, BAJA, (DESCEND)

Hechenle ganas! "