Prepared for GEOGRAPHIC EXPEDITIONS by
Ian R. WADE, Director
ADVENTURE SAFETY INTERNATIONAL

SUMMARY

This paper summarizes the current medical advice for preventing and treating illnesses related to travel at altitude. It is intended for guides and companies who organize programs at altitude to minimize the risk of severe illness affecting their clients.

After reviewing the various manifestations of altitude illness and their treatment, the paper discusses risk management. Protocols for prevention of altitude illness are suggested including:

• Screening of participants
• Expedition planning
• Travel procedures

Appendices include a bibliography, list of medical consultants, and sources for equipment.

Preparation of the paper involved review of recent publications, consulting with medical experts, and examining the operating practices of some professional adventure travel companies and guides. This information has been compiled from many sources, however Steve Boyer M.D., Peter Hackett M.D., David Shlim M.D., and Al Read of Geographic Expeditions were particularly helpful.

SYMPTOMS AND TREATMENT OF ALTITUDE ILLNESS

Travel to altitudes above 9,000-ft.can cause several types of illness. The two forms of altitude illness that are life threatening are:

• Acute Mountain Sickness (AMS), which may progress to cerebral edema, results from fluid accumulation in the brain.
• Pulmonary edema that results from fluid accumulation in the lungs.

Treatment of altitude illness will involve some combination of

1. Descent or rest
2. Hyperbaric bag usage
3. Oxygen administration
4. Medications

   GENERAL TREATMENT OF ALTITUDE ILLNESS
   Descent should always be the first consideration in treatment, or at least rest at the present altitude. Experienced guides insist that their groups follow these common sense rules:

   1. Don't go to a higher sleeping elevation if you feel bad or have any symptoms.
   2. If you don't get better, go down.
      A descent of 1,000 to 3,000 ft. may be needed to see improvement.

Acute Mountain Sickness
Some symptoms of AMS affects over 50% of travelers to altitudes over 12,000 ft.

Mild AMS often begins at around 8,000 ft.:

• The primary symptom is a headache that responds to aspirin, acetaminophen, or ibuprofen. Acetazolamide (Diamox) may relieve a headache due to AMS.

Other symptoms that may be present are:

• Nausea · Difficulty sleeping
• Lack of appetite · Undue fatigue, weakness
• Dizziness

Moderate AMS may involve additional symptoms such as:

• Vomiting once or twice.
• Headache that does not respond to aspirin, acetaminophen, or ibuprofen.

  TREATMENT OF MILD AND MODERATE AMS

  • Acetazolamide is the recommended treatment for mild or moderate AMS. The dose might start with 125 mg. taken an hour or two before bedtime and go up to 250 mg. taken twice a day until the subject recovers. Smaller doses have fewer side effects that include increased urinary output, tingling fingers, toes, and lips. Those allergic to sulfa drugs should consult with their physicians to try acetazolamide under controlled circumstances prior to altitude travel
  • Headache may be treated with aspirin, acetaminophen, or ibuprofen. Focussing on deeper breathing may also make headache symptoms disappear.
  • Persistent vomiting should be cause for descent. Suppositories are the preferred way to administer medication such as promethazine to treat vomiting. Compazine is not recommended as it may have muscular side effects (1).
  • Those with moderate AMS should stop ascending and begin descent if symptoms do not disappear overnight.

    Recovery from mild or moderate AMS may take 1-3 days after which ascent can resume.

High Altitude Cerebral Edema (HACE)
HACE is the most severe form of AMS and is caused by fluid accumulation in the brain. HACE has occurred at altitudes as low as 9,000 ft. Symptoms of mild or moderate AMS may be present however the definitive symptoms of HACE can include:

• Loss of balance (ataxia).
• Severe fatigue at rest.
• Decreased mental functioning.
• Inability to talk or make sense.
• Coma leading to death.

  TREATMENT OF HACE
  HACE is life threatening and immediate descent is the preferred treatment. Oxygen or use of a hyperbaric bag may be life saving for subjects with HACE. If the subject is mobile and conditions permit they should begin descent.

  • Dexamethasone (Decadron) is indicated. The dose is 4-6 mg. every 6 hours for up to 5 days.
  • Use of a hyperbaric chamber or oxygen may improve the subject's condition enough, if they are not mobile, for self-powered descent
  • Oxygen during descent would be helpful at a rate of 2-4 liters per minute.

If a subject recovers quickly from HACE they may attempt to reascend beyond the onset altitude, but only if prompt descent routes are available.

 

High Altitude Pulmonary Edema (HAPE)
HAPE results from fluid accumulation in the air sacs of the lungs. It is a life threatening condition that typically affects 1 or 2% of travelers to altitude and can occur as low as 9,000 ft.

The initial symptom of HAPE will usually be marked breathlessness and weakness with exercise.

Treatment for HAPE should begin at this point before onset of more severe symptoms such as:

• Severe breathlessness at rest with (respiratory rate over thirty a minute)
• Coughing, often dry in early stage but productive of foamy or bloody sputum later.

The following additional symptoms may be present:

• Rapid pulse.
• Extraordinary weakness.
• Fever may be present and respiratory infections increase risk of HAPE.
• Color may be bluer than companions (check fingernail beds).

  
  TREATMENT OF HAPE
  While descent is always the best option, a subject with mild HAPE symptoms may stay at altitude and take nifedipine (11). The dose is one or two 20 - 30 mg extended release tablets a day. This should be continued for 24 hours after symptoms disappear. If remaining at altitude pulse and respiration rates should be monitored for increases that would indicate a worsening of HAPE and indicate descent.

  A subject with severe HAPE would ideally be carried out to avoid worsening their symptoms due to exertion. Descent should not be delayed however.

  Use of a hyperbaric chamber or oxygen may improve the subject's condition enough, if they are not mobile, for self-powered descent.

  Oxygen during descent would be helpful at a rate of 2-4 liters per minute.

  Some subject's experience a drop in blood pressure taking nifedipine that can cause dizziness or fainting. A procedure for testing the subject is given in (1) if the subject intends to walk down taking nifedipine.

  If a subject recovers quickly from HAPE they may attempt to reascend at a prudent pace, taking nifedipine to prevent recurrence.

Sleep Disorders
Getting to sleep is often problematic at altitude. Most sleeping pills act as respiratory depressants and are not recommended as they may inhibit acclimatization.

Periodic breathing is relatively common especially above 15,000 ft. The subject will breathe rapidly then breathing will slow down or cease before resuming. Subjects can awake feeling anxious when this occurs; however the condition improves with acclimatization.

TREATMENT OF SLEEP DISORDERS
Periodic breathing is effectively treated with acetazolamide.

Difficulty sleeping may be treated with low doses of temazepam, which has only mild respiratory depressant qualities and a short half-life. Use after the first night at a new altitude with no AMS symptoms (6).

If noise is the cause of the sleep disorder, rather than altitude, earplugs may be an effective solution.

Peripheral Edema
Swelling of the hands, face, and ankles is common at altitude, affecting perhaps 20% of travelers to 14,000 ft. Edema is twice as common in women and more frequent in those with AMS. Having a ring appear tighter is a common sign of edema. Usually no treatment is required. While not serious alone, edema may be a sign of potential for other altitude illness.

TREATMENT OF PERIPHERAL EDEMA
If HAPE and HACE are absent, a diuretic such as furesemide may be taken in small doses of 20 to 40 mg orally a day. Fluid intake should be maintained.

Increased Urine Output
Diuresis can occasionally occur at altitudes above 10,000-ft. resulting in increased urine output. Subjects may urinate profusely as they acclimatize. This may not be case for alarm but rather a sign that fluid retention is ending as acclimatization takes place.

Blood Clots
Blood thickens in response to diuresis and the increase of red blood cells at altitude. Thicker blood can clot especially if subjects are inactive or if dehydration is present. Blood clots can migrate to the lungs (pulmonary embolism) causing a life-threatening condition. Deaths from "HAPE" that did not improve with descent may be due to pulmonary embolism.

Eye Problems
Bleeding in the retina of the eye may go unnoticed unless it involves the central vision when partial loss of vision is noticed. The condition is common above 15,000 ft. though rarely detected and usually resolves with descent.

Sore Throat
Sore throat and persistent cough from the dry air at altitude is common.

TREATMENT OF SORE THROAT

• Throat lozenges that can be sucked may be helpful.
• Breathing warmed air through an airway-warming mask.
• Inhaling steam may help severe cases.
• Increased fluid intake is beneficial.

Increased Susceptibility to Infections
Respiratory infections are common at altitude. They tend not to get better or to respond to antibiotics at altitudes above 16,000-ft. Use of antibiotics is recommended when symptoms of a viral cold do not improve after 5-days. Skin infections would be treated with antibiotics at the first sign of redness. It may be necessary to descend below 16,000-ft. to get rid of infections even with the help of antibiotics.

TREATMENT OF INCREASED SUSCEPTIBILITY TO INFECTIONS
Commonly used medications and dosages are:

AVOIDING AND REDUCING THE RISK OF ALTITUDE ILLNESS
Popular opinion, supported by media coverage, suggests that fatalities are inevitable for altitude travelers. The most widely respected statistic comes from Himalayan chronicler and historian Liz Hawley, that 2-½% of Himalayan climbers die from all causes. Falls and exhaustion are more common causes of death than altitude however.

Risk Management Goal
The goal for commercial operations must be to eliminate fatal or disabling illness and injury for clients.

To operate otherwise:

• Implies that less than the highest standard of care will be provided. Clients expect, when hiring a guide, to get experienced judgement and skill that they do not possess.
• It is simply bad for business to operate with any other standard. It creates the impression of helping people kill themselves.

Several actions can reduce or avoid the risk of developing altitude illness. These are summarized in three categories:

1. Screening of potential altitude travelers.
2. Planning itineraries and supplies.
3. Prevention activities during the altitude travel.

Screening of Participants for Altitude Travel
1. Screening clients ahead of participation is prudent, to identify those at higher risk of developing altitude illness:

1.1 Prior History of Altitude Illness
Some individuals have experienced AMS, HACE, or HAPE before. They may try again and do well at altitude. These subjects may take acetazolamide prophylactically rather than waiting for symptoms and have nifedipine available.

1.2 Obesity
Obesity is a predisposing factor for HAPE; however, the possibility of obese people volunteering for altitude travel is low. Tours where people are driven to altitude may experience greater health risk to obese participants.

1.3 Age
Children are not more susceptible to altitude illness than adults, despite some warnings to the contrary. Diagnosis of altitude illness may be more difficult however with children. Parents of minors should be warned about risk of altitude illness affecting their child. Older people, without other risk factors, may do better at altitude than younger people according to a report by Charles Houston, MD. (10)

1.4 Prior Experience at Altitude
Depending on the objective it may be appropriate to require some mountain experience.

Typical examples might include:

• Hiking at lower altitudes before trekking up to say 21,000 ft. at the Rongbuk Everest basecamp.
• An ascent of Rainier (14,000 ft.) before an ascent of McKinley or Aconcagua.
• An ascent of Aconcagua before an attempt on Everest.
  It is difficult to generalize, but the appropriate prerequisite experience should be considered as screening criteria for any trip to altitude.

2. Screening may also be done to identify those with the following conditions that may be aggravated by exercise at altitude:

2.1 Coronary risk
Blood pressure and heart rate increase as a normal response to exercise at altitude. Screening of participants for cardiac risk is an appropriate precaution.

The following cardiac risk factors and screening guidelines are adapted from references (1) and (5):

1. Severe angina, with restricted exercise at sea level or congestive heart failure.
2. Unexplained chest pain, pressure, shortness of breath, heart palpitations, sweats, exertional dizziness or fainting spells.
3. Diabetes requiring medication.
4. High blood pressure, even if treated with medication.
5. Smoker.
6. Abnormally high cholesterol level or special diet or medication for lipid abnormality.
7. Immediate family history of heart attack, coronary bypass surgery, angioplasty, or sudden unexplained death before the age of 55.

The screening guidelines suggested are:

Risk factor 1	Should not participate in altitude activities.
Risk factor 2 or 3	Males over 40 and females over 50 should be examined by a physician and undergo an exercise stress test.
Sedentary Lifestyle and any risk factors 4 - 7	Males over 40 and females over 50 should be examined by a physician and undergo an exercise stress test.
Active Lifestyle and two or more risk factors 4 - 7	Males over 40 and females over 50 should be examined by a physician and undergo an exercise stress test.

2.2 Pregnancy
There is little data on the effect of altitude on pregnancy. The first three months are suggested as the riskiest time (1). Women who sign up for altitude travel and then become pregnant should consider not going above 12,000 ft.

The use of oral contraceptive pills should be discouraged if spending extensive time at extreme altitude, as it theoretically increases the chance of blood clots. Trekkers or climbers to intermediate altitudes, such as Aconcagua, should not be affected.

2.3 Radial Keratotomy
Those who have undergone Radial Keratotomy eye surgery for myopia are at risk of severe visual disability at altitudes above 17,000 ft. These individuals should consult their optometrist to obtain alternate glasses for use at altitude (16).

2.4 Sickle Cell Disease
People suffering from Sickle Cell disease with a history of crises should not go above 8,000 ft. because of high risk of crisis.

2.5 Contact Lens
Hard contact lenses may not be well tolerated at altitude because the cornea becomes hypoxic. Soft lenses have been used successfully, however glasses may be an easier way to manage correction of eyesight. Those who need prescription glasses should obtain darkened lenses for their glacier glasses.

2.6 Seizure Disorder
People with seizure disorder must have demonstrated that their condition remains controlled by medication even during extreme exertion. Travel on technical terrain by those with seizure disorder presents hazards that many guides and other clients may be unwilling to accept.

2.7 Insulin Dependent Diabetics
Insulin dependent diabetics become more fragile at altitude perhaps because of inconsistent diet and irregular exercise regime. If unpredictable exercise levels are likely or food may not be readily consumed these individuals are at higher risk at altitude.

Self Screening - Disclosure of Risk
A final part of screening is giving the clients the chance to screen themselves out of the activity by providing appropriate warnings of the hazards involved. Clients need to know that the guide may not be able to assist them in some situations if they experience altitude or other illness and that they may die. For example at altitudes above 26,000-ft. the guide may not be physically or mentally able to assist, or evacuation may be delayed even at lower altitudes. The availability and expense of air or other evacuation methods should be clearly disclosed.

Disclosure of risks, and obtaining a signed assumption of risk statement will be helpful should legal action ensue. A waiver of right to sue, if company policy or regulations allow, would serve the same purpose.

Any risk factors identified during the medical screening process should be discussed with the client and notes kept if both parties agree to continue with the altitude travel after reviewing the risk factors.

Arrangements for disposal of the subject's body should be specified which might be cremation or simply leaving the body on the mountain.

Expedition Planning for Atlitude Travel
While the goal of risk management is to avoid altitude illness, it is necessary to be able to respond to any disabling condition that a client experiences. This implies attention to the following items:

1. Communication in the event of an emergency. The UIAA Recommended Code of Practice for High Altitude Guided Commercial Expeditions suggests that "walkie-talkies" be carried, presumably for communication with a lower camp in which a satellite phone is available. The phone could be used for seeking definitive medical advice or to summon air evacuation, if this is an option.
2. Provision for self-rescue by the group by having sufficient staff on call, equipment for evacuation, and medically trained support staff.
3. Rescue insurance or other arrangements to guarantee payment for rescue should be in place ahead of need. The clients' medical policy may cover this or separate insurance may be purchased.
4. Travelers to foreign countries should register with the Embassy of their home country so that negotiations for evacuation can be officially supported.

Route Selection
Program Design should consider
· The rate of ascent guidelines (next section)
· Having an evacuation method readily available to lower elevations e.g. yak, horse, camel, vehicle.
· Positioning of equipment needed for treatment of altitude illness in the most accessible places.

Equipment
For treating altitude illness a hyperbaric bag or oxygen may be life saving and should be taken when sleeping above 14,000-ft.:

Oxygen is a recommended treatment for HACE and HAPE. Oxygen may help subjects descend under their own power. Delivery rates vary from 2 up to 12 liters per minute (1). Carrying sufficient oxygen is problematic. A 1-day supply at 3 liters per minute would weigh around 90-lb. (15). A reasonable estimate of likely usage time must be made to determine the quantity of oxygen required.

Medicines
For treatment of altitude illness various medicines are widely recommended that have few side effects. Many doctors are willing to prescribe these medications for administration by guides with lower levels of medical training. Even controlled substances are routinely prescribed for control of pain with the proviso that records are kept of administration or disposal of these drugs. Every doctor contacted to comment on this paper reported contacting the Drug Enforcement Agency and receiving approval for writing these prescriptions for guides and guide services.

Some clients bring their own medications for altitude travel. The guide should be aware of all prescription medications being taken because of side effects or reactions with other drugs that the guide may administer. Clients who require ongoing medication should be identified during screening.

The medications previously mentioned, acetazolamide, dexamethasone, and nifedipine, should be carried specifically for treating AMC and HAPE. For treatment of peripheral edema and sleeping disorder guides might consider carrying furesemide and temazepam.

Guide Selection
Those who have successfully been to altitude at least as high as the contemplated travel would be favored as guides. It is desirable to allow time for the guide to acclimatize ahead of the client's arrival to minimize the chance of them becoming ill and being unable to assist the client. Familiarity with the route of travel is desirable but not always possible. Training of the guide should include recent review of reference material on altitude (1, 2, 12).

Communication Devices
With satellite communications one can now summon assistance or get expert advice from almost anywhere on earth (17). The price of satellite email systems is now under $1,000 and satellite phones may be purchased for $2,000 or rented. Depending on the distance to communication systems, consideration should be given to carrying one of these devices.

Expert Consultation
Satellite phones allow consultation with experts in the treatment of altitude illness or other medical conditions. Establishing relationships with medical experts who would be willing to consult in an emergency should be considered. A list of some experts is provided later.

Medical and Evacuation Capabilities
Determining the capacity of medical facilities adjacent to the route should be part of the planning process. The transport options to reach each facility including those with the highest levels of care, possibly in other countries, need to be established.

Travel Procedures to Prevent Altitude Illness

Rate of Ascent
The speed of acclimatization varies from person to person. General guidelines have been established (1 & 12) that prevents altitude illness for most people. Itineraries for groups should conform to these guidelines, or if terrain or other factors require they be exceeded, the option to rest or descend should be readily available.

Rate of Ascent guidelines above 10,000 ft.

• Climb as high as desired during the day but raise sleeping elevation by no more than 2,000 ft. each night.
• Build in an acclimatization day, with no sleeping altitude gain, every second or third day.
• Don't continue ascent with symptoms of altitude illness.
• Descend if symptoms don't go away with rest at the same altitude.

Some members of groups will require more time to acclimatize yet be reluctant to disclose their problems for fear of slowing others. The guide has several options: -

• If several group members have mild or moderate AMS symptoms then the whole group could rest until they are well.
• The group might be split into faster and slower parties if manpower and logistics permit.

Guides should not permit anyone to ascend to a higher sleeping altitude with symptoms of altitude illness. This may be a hard policy to enforce, making one unpopular with group members who have no symptoms. Experienced guides will insist however to ensure the safety of the clients under their care.

As well as overall rate of ascent, strenuous exercise may trigger the onset of altitude illness, especially HAPE. Guides should monitor those who undertake additional exercise during the day e.g. digging a snow cave or a strenuous day hike.

Medications
Medication may be used to prevent altitude illness as well as to treat it. The following are recommended prophylactic medications:

Aspirin is recommended for prevention of blood clots, a particular concern if resting at high altitude—The dose of one adult tablet every other day, or child size tablet daily, is sufficient.

Acetazolamide is FDA approved for preventing AMS and is recommended by most sources for people who:

• Travel rapidly to altitude.
• Exceed the rate of ascent guidelines.
• Have had previous problems at altitude.
  Most travelers to altitude will only take acetazolamide when symptoms develop rather than taking it prophylactically.
  • A dose of 125 mg. taken an hour or two before bedtime.

People allergic to sulfa drugs should test whether they can take acetazolamide at home rather than at altitude. It may also be useful to try acetazolamide at home to test for side effect tolerance.

Dexamethasone prevents illness without aiding acclimatization. People flying to altitude for brief periods, such as rescue work or those allergic to sulfa drugs and meeting the criteria for acetazolamide might consider it for use.
—The dose for prevention is 2 mg. every 6 hours for no more than 3 days.

Diet
Fluid intake is generally regarded as helpful in preventing altitude illness. There is insensible loss of water in the dry air of altitude that requires fluid replacement beyond what thirst alone might indicate. Clients need to be encouraged to drink regularly and to monitor urine output so that they achieve two full bladders daily with clear color urine.

Eating enough to replace calories consumed by exercise is desirable. A high carbohydrate diet is preferred (19). Fats have been shown to be 50% mal-absorbed whereas carbohydrates were 25% mal-absorbed in studies of individuals above 18,000-ft.

Avoid salty foods.

Early Diagnosis of Altitude Illness
Detecting symptoms of altitude illness early will help prevent more serious symptoms developing. Educating clients about the body's response to altitude will help reassure clients and attune them to early symptoms. The guide should inquire regularly of each individual about suspected symptoms in a way that encourages clients to speak up.

Decision Making
Recognizing that one's judgement at altitude may be impaired; it could help to listen to the advice of a person at lower altitude whose judgement may be more prudent. Establishing radio communication and being disciplined enough to act on the advice received would be critical for this strategy to be helpful.

Establishing and following pre-defined turnaround times, particularly on the summit day is another way to address changes in the guide's ability to make decisions.

Conclusion
The various illnesses associated with travel at altitude have been identified and currently recommended treatments summarized.

Reducing or avoiding the hazards associated with altitude travel affect the ways an organization selects clients and plans programs. Measures that the guide can adopt during the altitude travel to minimize problems have also been given.

Deciding which of these measures to adopt will always involve judgement on the part of the guide service and the guide as to, which are relevant to any particular trip and group of clients.

PHYSICIANS SPECIALIZING IN ALTITUDE MEDICINE

SOURCES OF EQUIPMENT FOR ALTITUDE ILLNESS

BIBLIOGRAPHY