Before the Trip

Travelers and their physicians should take an educated approach to the places they will visit and the people who will accompany them. Attention should be given to regional hazards and locally available health resources. For example, drinking water quality and treatment options, endemic infectious diseases, environmental exposures, and venomous animals should all be considered and studied. The diversity and burden of endemic infectious diseases are often underappreciated by foreigners. Although infections such as malaria, yellow fever, dengue fever, and schistosomiasis are commonly known, many region-specific endemic viral diseases (e.g., Japanese encephalitis), parasitic infections (e.g., kala-azar, visceral leishmaniasis, balamuthiasis) and devastating bacterial infections (e.g., cancrum oris [necrotizing stomatitis]) are less familiar to Western clinicians. For each geographic region of travel, the trip physician or medical advisor should take appropriate steps to understand local environmental hazards, venomous animals, and diseases, including their prevention and treatment. Malaria prophylaxis should be used based on the Centers for Disease Control and Prevention (CDC) or World Health Organization (WHO) recommendations (Box 91-1), and, in areas with mosquitoes, persons should carry mosquito nets and insect repellent containing a sufficiently high concentration of N,N-diethyl-m-toluamide (i.e., DEET; this substance can be purchased at up to 100% concentrations at most wilderness stores).

If a physician or designated medical leader accompanies the group, that person should obtain the medical history of each member, including vaccinations relevant to the area of travel, chronic diseases, surgical history, allergies, and regular medications (Appendix A). Travelers should receive destination-appropriate immunizations as far in advance of travel as possible.

One example of a vaccine requiring significant discussion before it is given is the rabies vaccine. Within the United States, rabies vaccination is only considered for those routinely exposed in close quarters to wild animals. This is due to the following facts: (1) the disease burden of rabies is relatively low; (2) the primary animal reservoir is in bats and skunks rather than in urban or domesticated animals; and (3) there is widespread availability of safe postexposure prophylaxis. When traveling outside of the United States to certain underdeveloped regions of the world, especially India and Central and South America, a large reservoir of disease is found in urban dogs. The behavioral changes (e.g., aggression, unpredictability) associated with active infection augment the exposure risk. Given rabies’ devastating prognosis, exposure risks should be discussed and an informed decision made regarding immunization versus postexposure treatment. Specific information about exposure criteria, postexposure prophylaxis, and recommendations for vaccination can be obtained from the CDC.

Dental problems should be treated before the trip, and diabetic travelers should be instructed to bring an ample supply of their routine medications along with a functioning and spare glucose meter. Musculoskeletal complaints from overuse are common during travel. Proper conditioning can reduce the incidence of these injuries, and group members should be encouraged to prepare for the trip by training in a way that simulates anticipated activities. For groups without trained medical leadership, physicians should address these issues with their patients before departure directly or with questionnaires (see Appendix A). When the group is not accompanied by a physician, the trip leader or coordinator assumes responsibility for assessing health limitations of the group. The coordinator should confidentially but frankly discuss medical problems with each candidate and require a pretrip formal medical evaluation if there exists uncertainty about the candidate’s medical suitability for the trip. Safety of the individual and the group are the coordinator’s first priorities. Box 91-2 addresses general preparedness for travel in developing countries.

Before the trip, consideration should be given to caffeine, alcohol, and drug dependencies. Management of such dependencies is a sensitive and complex issue unlikely to be satisfactorily resolved in a wilderness setting. Eliminating access to substances to which individuals have chronic dependencies will often cause hardship. For example, caffeine withdrawal is believed to be one of the leading causes of headaches among recreational trekkers at high altitude, and is often mistaken for a symptom of acute mountain sickness. Strategies for addressing dependencies should be discussed with both the individual member and group leader. Excess alcohol should be avoided, because it causes peripheral vasodilation, which can result in excessive heat gain in hot environments and heat loss in cold or wet environments. Alcohol tends to exacerbate symptoms of acute mountain sickness and should be avoided entirely at altitudes of more than 2438 m (8000 feet). In addition, alcohol’s effects on judgment and sensory perception may result in failure to acknowledge early symptoms of environmental illness.

An additional challenge facing the medical designee is allocation of opioid-containing analgesics, sleep agents, and other medications. Expedition members naturally hope to be as comfortable as possible and to sleep well, although these may be unreasonable expectations at times. Likewise, medical designees want to provide adequate treatment for pain and anxiety. Because of the potential for inappropriate use of these medications, it is advisable to limit access and consistently apply predetermined policies for the use of opioids and anxiolytics. Travelers should be advised to see their physicians about known sleep problems, jet lag, and chronic pain issues before departure.

Factors in Trip Planning

Primary considerations when planning a trip include the following: (1) health of the participants; (2) duration of the outing and availability of advanced medical assistance; (3) and risks imposed by the environment, including hazardous recreational activities that require use of specialized equipment and supplies. Excellent health of individual participants should not be used to dissuade the expedition physician from comprehensive trip preparation.

Healthy Participants

Even the most active and healthy individuals should begin a graduated exercise program at least 2 months before departure to minimize deleterious effects of muscular, metabolic, and mental fatigue. This is especially important for people traveling to high altitudes; aerobic capacity in a sedentary person drops about 4% for each 300 m (1000 feet) above the 1200-m (4000-foot) level, but the loss is only one-half as great in an aerobically fit individual.^6,11 Careful stretching of muscle groups may increase efficiency and lessen the likelihood of soft-tissue injury during exertion and minor accidents.

If excessive environmental heat is anticipated, preparatory exercise in a hot and humid environment (this can be simulated with sweat clothing) for 1 hour daily for at least 7 days before departure helps preserve plasma volume (aldosterone effect) and sweat rate while lowering myocardial oxygen demand and sweat sodium content.⁹ This acclimatization will be lost within a week if not maintained. Such conditioning should be practiced with caution because of the risk for dehydration.

People with Preexisting Medical Problems

Patients with preexisting medical conditions should discuss, in detail, their travel plans and request recommendations from their primary care physicians (see Chapter 34). It is advisable for the physician to speak to the trip coordinator about the itinerary if there are any doubts about medical clearance for the patient. At-risk patients should wear medical identification bracelets and be encouraged to acquire and manage their own medications. The trip medical provider should know about these illnesses and carry replacement medications provided by these individuals for safekeeping. Patients with a history of chronic obstructive pulmonary disease (COPD), asthma, heart disease, diabetes, allergies, or seizures require special consideration. Pulmonary hypertension, recent pulmonary embolism, history of recurrent spontaneous pneumothorax, sickle cell disease, and sleep apnea are considered absolute contraindications to high-altitude travel.

Patients with a history of significant allergic reactions should carry an epinephrine autoinjector or injectable epinephrine with a needle and syringe (see Bites and Stings, later). Patients with a history of seizures should continue routine medications and also carry an injectable form of benzodiazepine, such as lorazepam (Ativan). Suppositories may be appropriate if the party is traveling in a cool or cold environment or with children.

Participants with preexisting cardiopulmonary disease and those with some of the select medical problems described later in this chapter deserve special attention. Caution should be taken when people with a history of COPD or asthma are attempting high-altitude travel. A plan for rapid descent is essential, because people with asthma and COPD may experience difficulty as a result of hypoxia from high altitudes. Similarly, dry air, exercise, or noxious stimuli (e.g., smoke, red tide¹⁵) may exacerbate reactive airway disease. Thus, a plan for rapid treatment should be in place before departure. Exercise in cold, dry air may trigger wheezing. Poor air quality, a by-product of fossil fuel burning or even remote volcanic activity, along with winds that can “stir up” larger particulate matter such as dust or sand, can also cause irritation. In addition to carrying a β-agonist metered-dose inhaler, travelers with COPD or asthma should carry a 2-week course of an oral steroid (e.g., prednisone) plus a broad-spectrum oral antibiotic. Studies of aircraft pressurized to 2438-m (8000-foot) altitude reveal that people with moderately severe COPD may have significant dyspnea at this attitude. This may serve as a surrogate marker for the altitude to which such individuals can safely travel.^1,4 People with mild to moderate COPD should not sleep above 3048 m (10,000 feet) because of the potential for nocturnal desaturation.

Patients with a known history of significant cardiac disease should not participate in wilderness activities that require excessive exertion. During travel, these patients should continue routine medications and carry copies of their most recent electrocardiograms. They also need to know when to withhold medication (e.g., to not take blood pressure medication when lightheaded from dehydration).

Outdoor adventure travel can provoke angina among people with underlying heart disease. There is continued debate about the evaluation and advice a physician should provide to patients with cardiovascular disease. In general, people with predictable angina of mild to moderate level may engage in outdoor travel if they are able to exercise by Bruce protocol for at least 9 minutes; such individuals must moderate their activity in proportion to the decrease in available oxygen that limits work capacity at higher altitudes. As a guideline, activity levels should be titrated to not exceed a heart rate that is roughly 75% of one’s ischemic threshold. For those with unstable angina, congestive heart failure, or valvular disease such as aortic stenosis, vigorous adventure travel is contraindicated. A person with a history of cerebral transient ischemic attacks can participate in outdoor travel if attention is given to proper hydration and use of aspirin or other anticoagulants such as warfarin (Coumadin) or clopidogrel (Plavix) as prescribed by the treating physician.

Outdoor travel often disrupts the normal meal schedules of diabetic travelers. Insulin-dependent diabetic travelers should carry their own insulin and glucose meter. Although some individuals may need less insulin when participating in high levels of exercise such as backpacking, this phenomenon is not true for all. Patients should monitor their glucose at least twice a day, regardless of how well they feel, and modify their insulin regimen accordingly. Other group members in close contact with insulin-dependent diabetic travelers should know that the first two interventions for an ill-appearing diabetic person are a small amount of sugar under the tongue and measurement of blood glucose level. For those taking oral hypoglycemic agents with hypoglycemia refractory to sublingual sugar, injectable glucagon may be a worthwhile adjunct, provided there is the medical expertise to administer it and manage its commonly seen adverse effects. During air travel, an insulin-dependent diabetic person should take his or her daily dose of insulin and eat according to the local time (departure) schedule. For a diabetic person traveling eastbound across multiple time zones, the day is effectively shortened; on arrival, the person should eat and administer insulin in accordance with local time but reduce the dose by one third. For travel westbound, the day will lengthen, and a second dose of insulin after 18 hours of travel may be administered after glucose monitoring, if indicated.

Human immunodeficiency virus (HIV) infection should not preclude outdoor travel as long as the HIV-positive person pays meticulous attention to water disinfection and receives immunizations against pneumonia, influenza, hepatitis A, and hepatitis B.

Many prescription drugs predispose travelers to heat, cold, and altitude-related illnesses. Diuretic use may lead to intravascular volume contraction, impaired heat transfer to the skin, dehydration, and potentially life-threatening electrolyte abnormalities such as hypokalemia. People taking diuretics should carry a packaged electrolyte replacement (i.e., oral rehydration solution) and a source of potassium (e.g., dried bananas, potato chips). The anticholinergic action of antihistamines, phenothiazines, and tricyclic antidepressants may result in hypothalamic dysfunction and diminished sweating. Whenever possible, alternative preparations should be considered for use during wilderness travel.

Patients with serious medical allergies or active illnesses should have an appropriate medical identification bracelet, anklet, medallion, or wallet card and store their personal medications in a protected but accessible location in their pack. At a minimum, for each patient with a severe allergy, a second member of the expedition should be aware of the allergy and its appropriate treatment in case the patient becomes incapacitated during a severe acute allergic episode. Everyone should carry a complete personal medication list during travel, with both generic and brand names listed.

Education in First Aid and Wilderness Safety

Before departure, the trip coordinator should review emergency supplies with the group. He or she should demonstrate proper use of mechanical devices and discuss medication indications. Groups planning an extended or high-risk outing may wish to conduct a mock injury evaluation and management exercise. Participants should be encouraged to take general courses in first aid and wilderness safety. Some agencies that offer general and specialized training in skiing, mountaineering, river rafting, and other types of wilderness medicine are listed in Appendix B. Locally organized programs may be found through the American Red Cross, sporting goods stores, and continuing education departments of local colleges. Larger organizations such as the Wilderness Medical Society, which is a nonprofit academic society, offer regular conferences and workshops nationally as well as referral to a large member community of experienced clinicians, researchers, lecturers, and experts worldwide that can be used for advice when preparing for travel. The Wilderness Medical Society publishes both a magazine and an academic journal, Wilderness and Environmental Medicine, which may be useful resources.

Trip Duration and Availability of Medical Care

When serious illness or injury occurs, the longer the delay in obtaining advanced medical assistance, the more likely the irreversible loss of physiologic function, limb, or life. One must anticipate delays in care when in rural or remote areas, because the nearest physician or hospital may not be equipped to handle a major injury or illness. Party members should agree in advance about simple emergency distress signals, such as whistle or flashlight bursts in groups of three.

An important example is planning emergency access to a recompression chamber for members of a deep-sea diving expedition. A terrestrial example is a deeply penetrating arm laceration. As hours pass, the likelihood of infection grows. If the victim can reach trained and equipped medical help within a few hours, it will suffice to control bleeding and apply a sterile dressing held in place by improvised cravats or tape. If definitive care is more than several hours away, irrigation with water containing a topical disinfectant may be desirable. If the delay in care will be 6 hours or more, a decision must be made whether to close the wound before evacuating the victim (see Chapter 22). Estimated time delay depends on the type of rescue services, method of contact, terrain, weather, and number of able-bodied (i.e., carrying) people.

Manually evacuating a victim is an option, but requires a relatively mobile victim or generally a minimum of six carriers if the victim is immobilized. In this regard, it is important to know whether other groups might be trekking in the same vicinity. If access is controlled by permit, the administering agency should be asked about neighboring parties’ itineraries. The decision to carry a victim out must be based on a realistic appraisal of the time it will take messengers to reach aid versus the time, effort, and risk to the patient and other party members performing an evacuation unassisted by an outside party. The likelihood of mishap rises as trip duration increases; this is partly attributable to unpredictable weather and the cumulative effects of fatigue and repetitive strain injuries. In the case of a recognized need for evacuation, medical interventions like improvised splints, braces, and crutches enabling self-rescue (i.e., walking under one’s own power, with or without assistance) can be the difference between minor delays and costly, multiple-day evacuations involving search and rescue teams.

Long trips usually involve extensive planning, significant financial investment, and time away from work and loved ones. Nevertheless, party members can be reluctant to shorten the trip and likely would rather continue in the face of mild medical disability and equipment failure. Groups planning to be away from civilization for more than a week should have a maximally diversified list of medical and contingency items.

Environmental Risks: Clothing, Fabrics, and Activities

Discussion of the principles of heat transfer and the role of fabrics as each applies to any outdoor adventure is important. From animal furs and wool, to hemp and cottons, to rubber and synthetics, a range of fabrics have been used successfully to insulate against all types of thermal transfer. Although it is clearly possible to ascend the highest peaks and cross the hottest deserts without modern synthetics, few would argue that the benefits imparted by modern fabrics have not allowed for faster, farther, safer, and more comfortable travel. Thorough consideration of the environment—including ranges of elevation, temperature and humidity—is mandatory for all aspects of active and down time. Personal mosquito netting is a requirement when traveling in tropical areas with mosquitoes, even if pretravel vaccinations have been completed. Mosquitoes are vectors for many serious illnesses, and mosquito netting is a simple and effective barrier. Netting impregnated with permethrin mosquito repellent is widely available in outdoor shops, and so are long-lasting spray preparations for persons who wish to modify existing clothes and equipment. Many compact and sturdy hammocks are manufactured with built-in mosquito netting. A second hammock suspended under the shadow of the rainfly allows dry storage of field gear and clothes off the ground in areas with frequent rain.

Knowledge of terrain and environmental conditions is essential when selecting everything from socks to sleeping bags. A single manufacturer can easily have dozens of similar-looking sleeping bags with ratings from extreme cold to warm weather. Selecting the proper sleeping bag can be very expensive. Chapter 93 provides a dedicated discussion of fabric and clothing selection for wilderness travel.

Planning for Terrain and Risks of Activity

Weather, terrain, and activity interact to increase the risk for illness or injury. Particularly hazardous situations include winter climbing, mountaineering, skiing, and travel from low- to high-humidity environments. Potential obstacles must be figured into estimates of maximum delay to medical assistance. U.S. and global historic summary data indicating temperature ranges, winds, and duration, type, and amount of precipitation can be obtained from the National Climatic Data Center (see Box 91-1 and Appendix B). State and national park services and state climatology offices are also sources of such information about their territories. The National Weather Service office nearest the travel site can provide short-term forecasts and in many regions broadcasts weather information between 162.40 and 162.55 MHz VHF (see Appendix B).