Wilderness Preparation, Equipment, and Medical Supplies

Chapter 91 Wilderness Preparation, Equipment, and Medical Supplies

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Wilderness travel and recreation expose individuals to illness and injury far from medical care. Commonplace problems such as blisters, diarrhea, and dehydration may become serious obstacles to a journey, and major illness may go undiagnosed. Some wilderness activities may result in traumatic injuries that threaten life or limb. In experienced hands, the correct medications and equipment can greatly reduce the morbidity experienced by individuals who encounter medical problems in a remote setting. This chapter is organized into five parts. The first part is an overview of general preparation, including planning strategies and preventive measures, with additional attention to travelers with chronic medical conditions. The second part describes different types of medical kits and details specialized medical equipment. The third part describes various medications useful in the wilderness setting, followed by a discussion regarding preparation for common medical problems encountered in the wilderness. The final part suggests strategies for both organizing materials in a kit and estimating optimal quantities of supplies, taking into consideration the limited space and budgets commonly allocated to wilderness expeditions. This chapter is primarily concerned with terrestrial travel.


Limited studies exist regarding the statistical risk of injury in various environments and during various types of activity. The most extensive extant research has occurred in the fields of high-altitude and dive medicine, with limited studies in other fields, including desert,21 tropical, and aquatic environments. Significant and systematic research is required to better characterize injury and illness patterns.

Existing data that address outdoor travel suggest that traumatic injury (generally of a minor nature) exceeds medical illness by roughly threefold. When reviewing injury patterns, most are attributable to soft-tissue damage (e.g., abrasions, lacerations, sprains); serious dislocations and fractures account for less than 5% of all trauma. The lower extremities are by far the most likely to be involved in minor orthopedic injuries,16 emphasizing the importance of appropriate footwear selection and foot care.

Most medical illnesses reported by wilderness travelers are attributable to nonspecific syndromes, such as gastroenteritis or upper respiratory illness. These illnesses probably result in part from exposure to new pathogens and from travel conditions that preclude adequate preemptive hygiene measures. Other commonly reported medical problems include headache (exacerbated by high altitude), dyspepsia (from local food intolerance), dehydration, heat-related illness, dermatitis, sunburn, allergic reactions, blisters, and other integument-related problems.3,10,16

After excluding deaths from cardiac causes, drowning remains the number one cause of accidental death among outdoor participants. Ice and rock climbing generate a unique array of injuries, including traumatic death from severe head trauma. Environmental causes of illness predominantly relate to high altitudes and extremes of temperature.3,10,16,17 Awareness of weather patterns, participant condition, and journey duration are critical to ensure that appropriate first-aid equipment, not routinely found in most kits, is available to deal with relevant emergencies. Some recommendations for such supplies are covered in the section about specialized equipment (see Medical Kits and Equipment, later).

Planning Strategies, Preventive Measures, and Risk Factors for Wilderness Travel

Mode of travel, destination, duration, environment, and the number of people on any trip vary so much that, in reality, there is no perfect medical kit. Physicians face the challenge of advising travelers about medicines and medical equipment, knowing that their patients may face decisions they are not qualified or prepared to make. Travelers and their physicians must recognize the limits of everyone’s knowledge and seek appropriate consultation from physicians, books, wilderness medicine courses, experienced colleagues, and myriad high-quality Internet resources relevant to travel around the globe. Pretravel planning, resourcefulness, and the ability to communicate are key elements to minimize risk and successfully diagnose and treat medical problems in the wilderness. It cannot be overstated that, regardless of a physician’s prior wilderness medicine experience, it is essential to have detailed discussions with expedition leaders and past members regarding occurrence of medical problems, trauma, and usefulness of various medical supplies on previous, similar expeditions. Local rangers and emergency medical service personnel may provide valuable information about weather patterns and risks specific to local terrain. Climbers and mountaineers will benefit from reading Accidents in North American Mountaineering, an annual publication that describes and analyzes climbing injuries and fatalities occurring each year in North America; it is available at www.americanalpineclub.org/p/anam.

Familiarity with evacuation resources (e.g., helicopter rescue), communications devices (e.g., satellite phones), and Global Positioning System (GPS) devices is helpful. In the past, these items were prohibitively expensive, but they are now affordable. One can purchase a basic GPS unit for about $100 or rent one on a weekly or monthly basis. Like GPS units, satellite phones can be rented, charged by battery, or charged and recharged on car batteries or solar panels. In addition, GPS-equipped emergency alert communication devices exist that can be activated solely for the purpose of emergency rescue and medical aid. When activated, these devices—like in-home medical alert systems—globally locate the device using GPS technology and then connect the user (qualitatively or via bidirectional audio) with a 24/7 support network to direct an appropriate response.20 These devices can be purchased outright at a reasonable cost, and network support maintained for generally less than one would pay for satellite telephone services. In many countries, even in the developing world, a cellular telephone may have good reception, sometimes in remote areas. Using satellite or cell phones to activate a rescue can expedite patient care, but neither device should be regarded as a substitute for proper preparation and sound judgment during wilderness travel. Many of these devices require open space to send and receive, so forested areas can severely impair their function.

Rescue services in most mountainous regions outside the United States require accident insurance or a large amount of cash before helicopter transport. In many areas of the world, emergency helicopter transport will occur only if the patient can pay for services at the time of service. If traveling in these areas, expedition or trip members should work with group leaders to ensure that appropriate rescue and accident insurance coverage is obtained for all persons at risk for needing an evacuation. Many insurance companies (e.g., International SOS)12 exist for this purpose and provide medical evacuation coverage to a hospital for stabilization and then evacuation to the home county. There are also environment-specific medical evacuation options. For example, members of the American Alpine Club receive $5000 of global rescue coverage without altitude limitations.2

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).

BOX 91-1 Guidelines for Travel in Developing Countries

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.

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.

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.

Medical Kits and Equipment

Medical supplies may be broken down into five components (Boxes 91-3 to 91-8): (1) personal medical kit; (2) more comprehensive medical kit; (3) devices and medications for expeditions and the medically trained; (4) specialized equipment for particular environmental and recreational hazards; and (5) supplies stored in a vehicle.

BOX 91-4 Contents of a Comprehensive Community Medical Kit

TABLE 91-1 Portable Diagnostic Instruments for Wilderness Travel

Device Indication
Urine pregnancy test (e.g., Baby Check, Midstream, SureStep, or one of many other generic and name brands) Essential for evaluation of abdominal pain in women of childbearing age; a positive pregnancy test raises the possibility of ectopic pregnancy, and immediate evacuation should be considered
Glucometer (e.g., Therasense) Useful for routine diabetes management and for evaluation of ill-appearing diabetic individuals who may have a too-low or too-high serum glucose level
Fluorescein dye strips and fluorescent light sticks Evaluate for corneal abrasions; if present, the eye should be flushed, the lid flipped to search for a foreign body, and the patient treated with topical antibiotic drops or ointment
Hemoccult cards and developer Patients with traveler’s diarrhea and bloody stool should not be given loperamide or another antiperistaltic agent
Low-reading (hypothermia) thermometer (e.g., ADTEMP 419 digital) Essential for evaluation of hot or cold patients, particularly those for whom alternative diagnoses are being considered
Sphygmomanometer (blood-pressure cuff) Useful for accurate measurement of blood pressure, particularly in trauma patients and patients with tachycardia or altered mental status; may be used as an adjustable tourniquet
Stethoscope Useful for auscultation of the abdomen and chest, particularly to evaluate for the presence of wheezing, pulmonary edema, or pneumothorax
Urine test strips (e.g., Clinitek) Useful for evaluation of abdominal pain, urinary symptoms, and hyperglycemia; hyperglycemia and the presence of urine ketones suggest diabetic ketoacidosis
Chronometer with second hand Useful for accurate measurement of heart rate and respiratory rate; also important when planning evacuations
Magnifying glass For foreign-body identification and removal
Pulse oximeter (e.g., Respiron, Nonin) Provides finger-sized, digital, light-emitting diode readouts for estimating tissue oxygenation
End-tidal carbon dioxide detector (e.g., Nellcor) Colorimetric devices are available to help with confirmation of endotracheal tube placement; quantitative devices are coming to the market

BOX 91-6 Devices and Medications for the Medically Trained

Sep 7, 2016 | Posted by in EMERGENCY MEDICINE | Comments Off on Wilderness Preparation, Equipment, and Medical Supplies
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