mountain sickness when used in combination with Diamox (University of Iowa,
1995).
Moderate AMS requires advanced medications or immediate descent to
reverse the problem. Descending even a few hundred feet may help and definite
improvement will be seen in descents of 1,000-2,000 feet. 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. Severe AMS requires immediate descent to lower altitudes (2,000
- 4,000 feet). Supplemental oxygen may be helpful in reducing the effects of
altitude sicknesses but does not overcome all the difficulties that may result
from the lowered barometric pressure.
GAMOW BAG
This invention has revolutionized field treatment of high altitude
illnesses. The Gamow bag is basically a portable sealed chamber with a pump. The
principle of operation is identical to the hyperbaric chambers used in deep sea
diving. The person is placed inside the bag and it is inflated. Pumping the bag
full of air effectively increases the concentration of oxygen molecules and
therefore simulates a descent to lower altitude. In as little as 10 minutes the
bag creates an atmosphere that corresponds to that at 3,000 – 5,000 feet lower.
After 1-2 hours in the bag, the person’s body chemistry will have reset to the
lower altitude. This lasts for up to 12 hours outside of the bag which should be
enough time to travel to a lower altitude and allow for further acclimatization.
The bag and pump weigh about 14 pounds and are now carried on most major high
altitude expeditions. The gamow bag is particularly important where the
possibility of immediate descent is not feasible.
OTHER ALTITUDE-INDUCED ILLNESS
There are two other severe forms of altitude illness. Both of these
happen less frequently, especially to those who are properly acclimatized. When
they do occur, it is usually the result of an increase in elevation that is too
rapid for the body to adjust properly. For reasons not entirely understood, the
lack of oxygen and reduced pressure often results in leakage of fluid through
the capillary walls into either the lungs or the brain. Continuing to higher
altitudes without proper acclimatization can lead to potentially serious, even
life-threatening illnesses.
HIGH ALTITUDE PULMONARY EDEMA (HAPE)
High altitude pulmonary edema results from fluid buildup in the lungs.
The fluid in the lungs interferes with effective oxygen exchange. As the
condition becomes more severe, the level of oxygen in the bloodstream decreases,
and this can lead to cyanosis, impaired cerebral function, and death. Symptoms
include shortness of breath even at rest, tightness in the chest, marked fatigue,
a feeling of impending suffocation at night, weakness, and a persistent
productive cough bringing up white, watery, or frothy fluid (University of Iowa,
1995.). Confusion, and irrational behavior are signs that insufficient oxygen is
reaching the brain. One of the methods for testing for HAPE is to check recovery
time after exertion. Recovery time refers to the time after exertion that it
takes for heart rate and respiration to return to near normal. An increase in
this time may mean fluid is building up in the lungs. If a case of HAPE is
suspected an immediate descent is a necessary life-saving measure (2,000 – 4,000
feet). Anyone suffering from HAPE must be evacuated to a medical facility for
proper follow-up treatment. Early data suggests that nifedipine may have a
protective effect against high altitude pulmonary edema (University of Iowa,
1995).
HIGH ALTITUDE CEREBRAL EDEMA (HACE)
High altitude cerebral edema results from the swelling of brain tissue
from fluid leakage. Symptoms can include headache, loss of coordination (ataxia),
weakness, and decreasing levels of consciousness including, disorientation, loss
of memory, hallucinations, psychotic behavior, and coma. It generally occurs
after a week or more at high altitude. Severe instances can lead to death if not
treated quickly. Immediate descent is a necessary life-saving measure (2,000 -
4,000 feet). Anyone suffering from HACE must be evacuated to a medical facility
for proper follow-up treatment.
CONCLUSION
The importance of oxygen to the functioning of the human body is
critical. Thus the effect of decreased partial pressure of oxygen at higher
altitudes can be pronounced. Each individual adapts at a different speed to
exposure to altitude and it is hard to know who may be affected by altitude
sickness. There are no specific factors such as age, sex, or physical condition
that correlate with susceptibility to altitude sickness. Most people can go up
to 8,000 feet with minimal effect. Acclimatization is often accompanied by fluid
loss, so the ingestion of large amounts of fluid to remain properly hydrated is
important (at least 3-4 quarts per day). Urine output should be copious and
clear.
From the available studies on the effect of altitude on the human body
it would appear apparent that it is important to recognize symptoms early and
take corrective measures. Light activity during the day is better than sleeping
because respiration decreases during sleep, exacerbating the symptoms. The
avoidance of tobacco, alcohol, and other depressant drugs including,
barbiturates, tranquilizers, and sleeping pills is important. These depressants
further decrease the respiratory drive during sleep resulting in a worsening of
the symptoms. A high carbohydrate diet (more than 70% of your calories from
carbohydrates) while at altitude also appears to facilitate recovery.
A little planning and awareness can greatly decrease the chances of
altitude sickness. Recognizing early symptoms can result in the avoidance of
more serious consequences of altitude sickness. The human body is a complex
biochemical organism that requires an adequate supply of oxygen to function. The
ability of this organism to adjust to a wide range of conditions is a testament
to its survivability. The decreased partial pressure of oxygen with increasing
altitude is one of these adaptations.
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