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Altitude illness is a mysterious malady, with no definite factors why
certain people are more susceptible than others. If you havenít been to
altitudes above 8,000 feet be careful. If you have been at these altitudes with
no problems, you will probably be fine as long as you are properly acclimatized.
There are three defined levels of altitude, High (8,000-12,000 feet),
Very High (12,000-18,000 feet), and Extremely High (18,000 feet or higher). At
sea level the concentration of oxygen is approximately 21% with the barometric
pressure averaging about 760 mmHg. As you go higher the barometric pressure
falls, giving you less oxygen molecules per breath. Your breathing will increase
to as your body tries to properly oxygenate the blood. This increases the oxygen
levels in the blood, but not to the same concentration as at sea level. Lower
air pressure and high altitude causes fluid to leak from the capillaries and
causes fluid build-up in both the lungs and the brain. You must properly
acclimatize before continuing higher or you risk potentially serious, even life-
threatening illnesses.
The principal cause of altitude illness is going too high too fast.
Acclimatization is the process the body goes through to increase the oxygen
delivery to cells and improve efficiency of oxygen use. The body starts adapting
almost immediately and can continue for several days or even weeks to completely
acclimatize. Some people adjust quickly while others never acclimatize, even
with gradual exposure over a period of weeks. Generally, it takes from 1-3 days
to acclimatize to a certain altitude, but if you climb any higher the body has
to adapt to the new elevation.
There are six factors that affect the incidence and severity of altitude
illness: 1) Rate of Ascent - you are at greater risk when you ascend quickly. 2) Altitude Achieved - the risk increases the higher your sleep. 3) Exposure Length - the longer your stay at high altitude, the greater the risk 4)
Exertion Level - continued strenuous exertion, without hydration or rest,
increases risk. 5)
Hydration - your risk increase with dehydration and the consumption of high fat
and high protein meals. 6)
Susceptibility - some people are physiologically more likely to become sick than
others. Here are some basic guidelines for proper acclimatization: 1) Don't fly or drive to high altitudes. It is best to walk
up from about 10,000 feet to your desires elevation. 2) If you absolutely have to fly or drive, it is best if you
do not over-exert yourself or move higher for at least 24 hours. 3) If you are going above 10,000 feet, increase your altitude
by about 1,000 feet per day and take a rest day for every 3,000 feet of
elevation gain. 4) If you are ascending more than a 1,000 feet per day, come
down at night and sleep at lower elevation. The old climbers saying is ìclimb
high and sleep lowî. 5) If you start to have moderate symptoms of altitude illness,
do not continue higher until the symptoms diminish. 6) If symptoms increase, even after rest and hydration, descend immediately. 7) If there are several members to your party, make sure
everyone is properly acclimatized before going higher. People acclimatize at
varying rates. 8) Keep properly hydrated. Fluid loss is often accompanied by
acclimatization, so drinks plenty of water (not drinks containing caffeine, they
will dehydrate you). 9) When you first get up to altitude, take it easy. Light
exertion during the day is preferred over sleep, because your respiration
decrease while you sleep and this will exacerbate the symptoms. 10)
Avoid tobacco, alcohol, and other depressants. Depressants decrease the
respiratory drive during sleep which worsens the symptoms further. 11)
While at altitude, eat a high carbohydrate diet (70% or more of your calories
should be from carbohydrates).
There are three common forms of altitude illness: 1)
Acute Mountain Sickness (AMS) - this is the most common. It is not life
threatening but if not treated, it can progress into High Altitude Edema or High
Altitude Cerebral Edema. 2)
High Altitude Pulmonary Edema (HAPE) - it is less common the AMS but more
serious. 3)
High Altitude Cerebral Edema (HACE) - the condition is rare but can be sudden
and severe at onset. Acute
Mountain Sickness (AMS)
Acute mountain sickness is a group of symptoms that are apt to occur in
people who are not acclimatized and make a rapid ascent to 8,000 feet and above.
It also occurs in partially acclimatized people who make sudden ascents to
higher altitudes. During the process of acclimatizing, many people experience
mild AMS symptoms. Symptoms usually start 6 to 72 hours after arrival at high
altitude and routinely disappear in 2 to 6 days. The symptoms seem to be worst
in the morning, most likely due to the normal decrease in rate and depth of
breathing during sleep.
Symptoms of AMS are: *
Headache - the body will increase the blood flow to the cerebral area to
maintain its oxygen supply, but this will expand the volume which causes pain as
the system adapts. *
Malaise - a general uneasy feeling due to decreased oxygen in the blood. This
lower level of oxygen will also cause dizziness and fatigue as well.
* Shortness of Breath - this is the body trying to increase oxygen
intake. *
Loss of Appetite, Nausea, & Vomiting - the function of the gastrointestinal
tract is decreased and compromised due the body redirecting the majority of the
blood flow to the major organs (brain, heart and lungs). *
Disturbed Sleep - while sleeping at altitude your rate and depth of respiration
may gradually increase until it reaches a climax and then it will stop entirely
for 5 - 50 seconds. This is called Cheyne-Stokes respiration, breathing that
further diminishes oxygen levels in the blood. *
Peripheral Edema - you may retain fluid, resulting edema, particularly of the
face and hands. *
Cyanosis - due to the decrease in oxygen saturation in the blood you will
experience a bluish appearance around the mouth, in the fingernail beds and
mucous membranes.
Treatment for Acute mountain sickness consists of increased hydration,
rest and descending if necessary. While at altitudes greater than 8,000 feet,
limit your activity for the first three days; it may take 3 - 4 days to
acclimatize. Drink generous amounts of water to help flush bicarbonate from the
kidneys. To relieve the headache, aspirin, ibuprofen or acetaminophen may to the
trick. If your symptoms become more severe, you start showing signs of ataxia or
pulmonary edema or your level of consciousness changes, descend! Usually
descending 2,000 - 3,000 feet is adequate. High
Altitude Pulmonary Edema (HAPE)
High Altitude Pulmonary Edema is caused by fluid build-up in the lungs,
which prevents effective oxygen exchange. If the condition becomes more severe,
the level of oxygen in the bloodstream diminishes, and the result can be
cyanosis, impaired cerebral function, and death. The cause is not clearly
understood. HAPE is more common in young males and rarely occurs below 8,000
feet.
The initial symptoms are similar to AMS, dry cough, shortness of breath
and fatigue while climbing uphill. Heart rate and respiratory rate will
increase, and possibly cyanosis of the fingernail beds. As HAPE worsens,
weakness, fatigue and shortness of breath occur even while walking on level
terrain. The heart and respiratory rate will remain elevated with additional
symptoms such as a harsh cough, loss of appetite and headache. These signs and
symptoms could be mistaken for the ìfluî, bronchitis or pneumonia.
When HAPE becomes more severe, you will experience a productive cough
(white, watery, or frothy fluid), extreme weakness and shortness of breath while
at rest. Heart rate will be greater than 110 beats per minute, and respiratory
rate will be greater than 30 breaths per minute. You will hear a ìrattlingî
sound (rales) in the chest even without a stethoscope. The cough will then
produce a frothy blood-tinged sputum. You then will become lethargic, ataxic
(loss of coordination) or unconscious. HAPE will become worse while sleeping due
to the above mentioned Cheyne-Stokes respiration.
HAPE is a life-threatening illness!
Immediately upon realization that you or a companion is experiencing HAPE,
descend at least 2,000 - 4,000 feet in elevation. If possible, give oxygen. If
the symptoms do not improve, continue descending until they do. Cold stress can
worsen HAPE, so keep the individual warm. Avoid exercise for 2 to 3 days while
the fluid in the lungs are reabsorbed. A person with moderate to severe HAPE
must be evacuated from the mountain to a hospital. High Altitude Cerebral Edema (HACE)
HACE generally occurs at altitudes above 12,000 feet, but an occurrence
has been recorded as low as 10,000 feet. It also generally happens after a week
or more at high altitude.
HACE is caused by swelling of the brain due to fluid leakage. Symptoms
can include headache, nausea, vomiting, ataxia, weakness, cyanois, and
decreasing levels of consciousness including, disorientation, loss of memory,
hallucinations, psychotic behavior, and coma. Paralysis and seizures may also
occur. If not treated quickly, severe cases can lead to death.
Do not wait for symptoms to get better, descend immediately as soon as
you notice any ataxia or change in the level of consciousness. Descending is
quit literally a life-saving measure. Descend at least 2,000 to 4,000 feet and
give oxygen if possible. Anyone
suffering from HACE must be taken to a hospital or medical facility for proper
follow-up treatment. Thromboplebitis
To treat a person suffering with thromboplebitis, loosen any constrictive
clothing (such as gaiters), give 1 or 2 aspirin every four hours to decrease the
bloodís ability to clot and to ease the pain. The individual should then be
carried down from altitude. |
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