Wednesday, July 7, 2010

Guide to Altitude Sickness


Several years ago I was hiking with my roommate on Mt. San Gregorino, the highest peak in southern california, we had just cleared the tree line and were approaching 10,000ft. My mild headache suddenly blossomed into throbbing globe that enshrouded my head in a fog, my finger tips went numb, my thoughts became cloudy, and I began stumbling around. I looked around at the desolate and grey moonscape before me. I looked across the valley below, down to Mt. San Jacinto and Palm Springs then I cast my eyes up the the summit just an hour away and then I decided to turn around.

Climbing and Hiking in the western united states means ascending to the alpine world where the air is thin and staying in tune with your body is mandatory. Unless our bodies are given a chance to adjust (aka. acclimate) the thin air above the trees won't be enough for our lungs. Understanding how this environment effects our bodies and what the warning signs are is the most important way to stay safe. This guide will cover:

1. Acclimation
2. Identifying Symptoms
3. Treatment Options


Acclimation


The goal of a trip into the mountains is the enjoy it, knowing about Altitude Sicknesses is important for surviving but the objective is not merely to survive. Our lungs are calibrated to absorb oxygen at whatever altitude we are usually at and they will re-calibrate when we move to another altitude where the air is thicker. Unfortunately this process can be slow and until our lungs have re-calibrated and can make the most of thin air above the trees we will have trouble exerting ourselves and can even develop altitude sicknesses.
One or two days at moderate elevation can prepare us to head up to higher elevations. The key is to make the ascent a slow process. The absolute ideal is to camp at 9,000-10,000ft, and day hike above 12,000 before returning to the initial camp. The next day the body should be adjusted to 12,000ft and would allow a push higher up to the roof of the western US at 14,000ft.



Identifying the Symptoms of Altitude Sickness



Mild AMS Severe AMS HAPE & HACE
HeadacheNausea & VomitingShortness of Breath even at rest
DizzinessDeclining CoordinationPresistent Cough
FatigueLoss of Mental Faculties Hallucinations
Shortness of BreathNumbnessTotal Loss of Coordination
Tingling in extremities Intermittent Consciousness


Acute Mountain Sickness (AMS)


Acute Mountain Sickness is quite common and a minor case can even go unnoticed, it is simply a case of being oxygen starved. AMS alone is not life threatening but if left untreated it can merely be a stop on the way to HAPE or HACE, life threatening conditions. Mild AMS is a yellow light, a clear indication to stop the ascent, at the very least long enough to let your body catch up with the altitude. You can not "push through" AMS, it will only get worse. If at rest the symptoms fade it may be safe to continue on. If, however, it does get worse and becomes severe AMS, descend immediately. A hiker or climbers condition can deteriorate rapidly and may be unable to help themselves if they develop HACE or HAPE. AMS alone however is not a life threatening condition.
Treatment Options for AMS
Pain Medications can be taken to help with a headache, personally however I've felt it to be important to be in tune with my body. Paid Med's may mask the headache but will do nothing to treat AMS itself. For Mild AMS it may be possible to keep going after a long break of an hour or so if you have simply overexerted yourself. Stopping and setting up camp and sleeping it off may be the best option. If symptoms are severe enough however descent is the only safe course of action.


High Altitude Pulmonary Edema (HAPE)


HAPE is far less common than AMS, it usually follows AMS but can develop suddenly and without prior symptoms. It is most common at very high altitudes and usually develops after extended exposure. Fluid begins to build up in the lungs preventing them from taking in enough oxygen which increases the risk of HACE. Difficulty breathing even at rest, or the feeling of suffocation or if a hiker/climber begins coughing up white/frothy liquid descend immediately. If after prolonged rest a hiker or climber is not recovering from exertion their lungs may be filling with fluid and they may have HAPE. HAPE is a life threatening condition so when in doubt, assume HAPE.
Treatment Options for HAPE
Once HAPE sets in it will continue to get worse. Rapid descent should be immediate and is necessary as well as potentially life-saving. 2,000-4,000ft. should be sufficient however because of the severity of HAPE the trip is already over and a return to the lowest elevation possible is advisable.


High Altitude Cerebral Edema (HACE)


The most severe and life threatening condition that can develop in the mountains is HACE. If HACE develops all efforts should immediately be poured into assisting the hiker/climber descend. HACE is fortunately quite rare and usually only develops after a long exposure to altitude or a persistent neglect of the symptoms of AMS or HAPE. HACE begins when the brain swells as a result of fluid loss and leads to a rapid deterioration in a hiker or climbers condition. HACE can set in rapidly and without warning so if a fellow hiker/climber fails a "sobriety test" they should descend immediately.
Treatment Options for HACE
High-Altitude Cerebral Edema is as life threatening as an avalanche. Descent out of altitude, at least 2,000 - 4,000 ft is mandatory if the hiker or climber is to live. HACE can not be slept off. It can temporarily be treated with Dexamethasone, however this should only used in assisting the descent. Dexamethasone will temporarily halt the worsening of HACE and allow window for the afflicted to assist in their own rescue.


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