- Email: [email protected]
An introduction to wilderness medicine
Emerg Med Clin N Am 22 (2004) 265–279
An introduction to wilderness medicine J. Matthew Sholl, MDa,*, Edward P. Curcio III, MDb a
Department of Emergency Medicine, Maine Medical Center, 22 Bramhall Street, Portland, ME 04012, USA b Department of Emergency Medicine, Mount Auburn Hospital, 330 Mount Auburn Street, Cambridge, MA 02138, USA
Outdoor and wilderness activities are the fastest growing recreational activities in the United States [1]. Newer activities such as mountain biking, snowboarding, and sea kayaking have become extremely popular in the past decades, whereas older activities such as mountaineering, rock climbing and ice climbing have recently found a new birth and are enjoyed by many newcomers each year. Some of these pursuits have become increasingly dangerous and ‘‘extreme,’’ with participants pushing the boundaries of safety and security. As more individuals are becoming ever more involved in outdoor activities, there is an increasing need for care and counseling in traditional and nontraditional settings. In response to this increase in activity, and in an attempt to provide assistance to those living and performing at the extremes of human experience, the dynamic and evolving field of wilderness medicine has developed; however, just as disparate as the various environments that make up the wilderness are the various understandings of the true definition of wilderness medicine. The core content of wilderness medicine is perhaps an easier question and is made up of the various topics contained in this text and others that are not included (Box 1). Combined, these topics attempt to cover the dissimilar realms that make up the wilderness and wilderness medicine. This article examines wilderness medicine in its current state and attempts to define this developing field of medicine.
* Corresponding author. E-mail address: [email protected] (J.M. Sholl). 0733-8627/04/$ - see front matter Ó 2004 Elsevier Inc. All rights reserved. doi:10.1016/j.emc.2004.01.001
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Box 1. Areas of wilderness medicine Trauma, including orthopedic care Altitude Animal bites Arachnid envenomations Snake envenomations Cold injuries, including frostbite and hypothermia Heat illnesses Toxic plant exposures Parasitism and tropical medicine Travel medicine Emergency veterinary care Search and rescue Diving accidents and dysbarism Submersion and immersion injuries White water medicine and rescue Open water medicine and survival Improvisation Aeromedical rescue Avalanche and crevasse rescue Survival and wilderness navigation Natural disaster management Wilderness management of chronic medical diseases Emergency medical services (EMS) and wilderness EMS Education
Defining wilderness and wilderness medicine Perhaps the natural place to begin when defining wilderness medicine is to first examine the definition of wilderness. The term ‘‘wilderness’’ might have different meanings for different people. A traditional definition of wilderness includes ‘‘(a) a tract or region uncultivated and uninhabited by human beings, and (b) an area essentially undisturbed by human activity together with its naturally developed life community’’ [2]. Many individuals define wilderness in terms of topographical or regional terms, such as a favorite trail or camping site, a particular mountain, a National or State Park, a local preserve, or an unnamed backcountry area. Others are more specific and define wilderness in part by the activities that bring them to the area (eg, rock or ice climbing, mountaineering, kayaking, caving, or backcountry skiing). In an attempt to draw together these varying descriptions, this article borrows from the wilderness EMS arena and begins by defining wilderness in terms of time from definitive care, typically 1 to 2 hours from hospital-based care. While not focusing on the
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geographical particulars or physical activities involved, this definition remains inclusive and might involve a multitude of environments and activities. When specifically examining medical care, this definition embraces many fields of medicine that are traditionally considered to be dissimilar, including wilderness medicine, tactical/military medicine, and disaster medicine. Closer examination, however, reveals that these fields share four core components: (1) their austere nature; (2) roots in traditional prehospital medicine with, at times, necessity for expanded care protocols or expanded patient care; (3) integration of medical and rescue skills; and (4) inherent threats encountered in each environment (Figure 1). Disasters commonly destroy or overwhelm a community’s infrastructure and stress the local medical providers, causing a unique ‘‘wilderness’’ in an otherwise urban setting. Tactical medical providers work under obvious threat and are frequently trained in expanded prehospital protocols. These providers might also find themselves operating in an urban or suburban setting but remain distant from definitive care because of ongoing threats to themselves or their team. Military medicine and wilderness medicine share common roots, and the experiences of in-field trauma management in North Korea and Vietnam helped develop protocols and practices for civilian applications. Using the previously mentioned definition of ‘‘wilderness’’ might be inclusive enough to include some traditional, rural EMS systems as well. While a good starting point, time from definitive care alone cannot capture the essence of wilderness medicine; time-based boundaries might well define an area of wilderness but lack in ability to define wilderness medicine specifically. One argument suggests that the true definition of wilderness medicine must involve consideration of the injury location. For instance, a climber who has high altitude pulmonary edema at Camp Muir, an Appalachian Trail through hiker with an injured ankle, and a near-drowning victim on the Colorado river are all obvious ‘‘wilderness medicine’’ patients, purely based on the physical location in which their injuries occurred. A second aspect of this definition involves the activity that brought the patient to said location: hiking, climbing, whitewater or sea kayaking, skiing, hunting, and
Each apparently different field of medicine shares in common their austere nature, with overwhelmedresources, threatening environment, and occasional delay to definitive care. The quintessential nature of each lays in the pre-hospital provision of care and at times demands prolonged patient care, expanded care protocols, and integration of medicine and rescue.
Wilderness
Tactical/Military
Disaster
Fig. 1. Overlapping realms of wilderness tactical/military and disaster medicine.
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so forth. Difficulty comes, however, in different individuals’ appreciation of what defines a ‘‘wilderness’’ location. Natural parks or uninhabited areas might be accepted as wilderness by most, whereas many would debate whether or not ski slopes, with established ski patrols and in proximity to urban or rural settings, can be defined as wilderness. Recreational and resort communities, which often border rugged wilderness areas, further blur the boundaries of wilderness. Still a third definition of wilderness medicine would stress the injury itself. Hypothermia, whether encountered on the summit of a mountain or in the back alleys of an urban city, is ‘‘wilderness medicine,’’ an injury resulting from the direct interaction between humans and their environment. Other obvious additions based on this definition would include mammalian and arthropod bites, envenomations, heat injuries, and altitude illnesses, to name a few. Many of these instances are more common in urban or suburban settings (hypothermia, heat illness, lightning injuries, and submersion) [3]. All would agree that the heart and soul of wilderness medicine includes a sense of connection with and stewardship for the wilderness. Individuals engaging in any wilderness activity for recreational or professional (including medical) causes usually share a deep bond with the natural world. The field of wilderness medicine allows for many to marry their professional occupation and its curiosities with their extracurricular passions. The proper definition of wilderness medicine must involve all these concepts: location where the injury occurred, time to definitive care, and type of injury, with particular attention toward those injuries that are directly related to human interaction with the environment. After examining these factors, one begins to discover the essence of wilderness medicine: injuries and illnesses caused by the interaction between humans and their natural environment occurring in potentially austere and threatening environments. The range and arenas of wilderness medicine can be equally incongruent. By virtue of its varied scope, wilderness medicine cannot be owned by any one traditional field of medicine. Indeed, wilderness medicine shares similarities with emergency medicine, primary care and internal medicine, occupational medicine, sports medicine, military medicine, infectious disease, pulmonary medicine, trauma surgery, and orthopedics, to name a few. Perhaps broader-based specialties are best equipped to address the breadth of wilderness medical injuries and illnesses, but even so, these providers must at times consult upon the expertise of their specialized colleagues, including those proficient in nonmedical skills such as wilderness guides and rescue personnel. While many wilderness medicine patients inevitably present to traditional centers of care, the essence and roots of wilderness medicine rest in the out-of-hospital delivery of care or in-field care. Wilderness medical providers who offer prehospital care might find themselves in tremendously different arenas. For example, the expedition medical provider or ‘‘trip doctor’’ comes prepared with full knowledge of the environment he or she is entering, and in many cases this provider has the
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ability to obtain past history of those being cared for and has time to adequately prepare for expected medical ailments. These providers are limited only by the weight they can carry and their imagination when preparing medical threat assessments. Meanwhile, the search and rescue provider is more akin to the traditional emergency medical provider and has limited knowledge of those being cared for and incomplete knowledge of the setting in which the patient can be found. These providers must carry a broad array of medical and rescue supplies while working under less than opportune circumstances but have at their assistance the local wilderness EMS system of care. Finally, wilderness medicine can occur to ‘‘innocent bystanders,’’ physicians, nurses, EMS providers, or laypersons not expecting to come across a trip mate or stranger who is injured or ill. It is this unforeseen wilderness medical provider who is perhaps pushed most to his or her limits, forced to provide care with limited resources and accessing a sometimes-difficult system of care. All of these providers must struggle against the factors that make wilderness medicine so challenging—critical elements that, along with time to care, location of injury and injury type, help define wilderness medicine as a unique and dynamic field: resource limitation and allocation; environmental impact on the patient, rescuer, and resources; evacuation difficulties; limited personnel providing care; and emotional, mental and physical preparedness necessary to provide care in the wilderness. Challenges of wilderness medicine It is perhaps easiest to examine these factors in a case-based setting while contrasting with common or traditional care. Patient #1, a 40-year-old man, falls 12 feet down a flight of stairs while at his Beacon Hill home in Boston, while patient #2, again a 40-year-old man, sustains a 12-foot leader fall while ice climbing Pinnacle gully on the flanks of Mount Washington in New Hampshire in February. In the urban environment, a simple phone call to 911 begins a cascade of events meant to maximize patient care. The phone call goes to a central agency, which then dispatches the closest prehospital provider. In Boston, the fire department and EMS race to the scene. Arrival time occurs in minutes, for finding the patient is just a matter of finding an address. Equipment is brought a few feet from the truck into the patient’s home, the only crux on the approach is perhaps a flight of stairs. On-scene care is managed inside the house or ambulance, far away from the threat of inclement weather. Patient #1 is found at the bottom of the stairs, unable to get up because of a fractured femur. Care starts with a rapid patient assessment, stabilization of the fractured femur, and administration of intravenous (IV) fluids. A cervical collar is left in the truck by mistake and a medic runs back to the truck to get the correct piece of equipment. The patient is stabilized and quickly placed on a backboard to ease extrication. Whisked from his home, he is placed quickly in a warm and dry truck as the
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medics contact the nearest hospital to alert them of their arrival. An emergency medicine physician trained in the latest Advanced Trauma Life Support (ATLS) and prehospital protocols provides medical control, and within minutes the patient is at the hospital receiving definitive care. In the ice gully on Mount Washington, patient #2 moans in response to the fall. Still attached to the rope, his climbing partner strains to set up a system to free himself. Minutes pass rapidly as he finally extricates himself from the rope system and comes to his friend’s aid. He approaches carefully, ever alert for avalanche danger and falling ice from above. He quickly realizes that his friend is gravely injured by the strange angle his leg juts from his harness. He places a tarp down and covers his injured partner with a sleeping bag, for he knows that the fractured leg is not the only threat; the cold of the mountain starts to slowly impact his friend’s health. He attempts to use his cell phone to contact help, but it does not function in the cold air, far away from any cell tower. He makes a tough decision and decides to go for help. The closest ranger station is 3 hours away, and he quickly descends the mountain. When he arrives at the ranger station, a call goes out to the local search and rescue team, a mix of volunteers who have various medical and rescue experience and who can break free from their jobs and family and arrive at the base of Mount Washington within 1 hour. As they gear up for the 4-hour approach, a splint bag is left inadvertently behind. They start up the mountain, single file, their headlights shining on the fresh snow, which has started to fall. Tired, they finally arrive on scene 8 hours after the initial injury occurred. As they begin to care for patient #2, they are challenged by cloaking darkness, the threat of falling ice, and the constant cold. An IV is attempted, but frigid fingers miss the vein, a second attempt is successful, and a bag of normal saline, kept warm inside a rescuer’s coat, is slowly infused. As they attempt to stabilize the fractured femur, they discover that the wayward bag is missing. A discussion occurs. To retrieve the bag is a 7-hour endeavor, so a decision is made to improvise a splint. Realizing that an exit at night is impossible, they set up tents, make dinner, and set up a watch system. Morning slowly arrives as their patient begins to slip in and out of consciousness; the stress of the fractured femur coupled with the cold has started to take its toll. No more IV fluid is available, and shock has set in. The rescue team would like guidance through medical control, but communication remains impossible. At daybreak, the rescue team begins extrication. First preparing the patient for litter travel with a hypothermia wrap, they place him in the litter and begin the hike out. The 3-hour hike takes 6 hours while carrying the litter, and the patient is comatose upon arrival the ranger station. It is here that our wilderness patient first encounters the traditional medical system. A heated ambulance awaits him at the ranger station, where fresh emergency medicine technicians (EMTs) begin to work on the patient. Warmed IV fluids are started and he is placed carefully in the ambulance and rushed to the nearest hospital. His situation
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is guarded upon arrival, but he unfortunately passes away during his extended hospital stay, a victim of his fractured femur, hypothermia, and prolonged extrication. These two vignettes are representative of many wilderness medical systems and shine light on the critical features of wilderness medicine. Time is a decisive element in wilderness medicine, and in some instances it helps to define an event as ‘‘wilderness.’’ Patient #2’s scenario is not uncommon in many parts of the world. While urban and even rural settings operate within the modern time restraints of the ‘‘golden hour’’ to definitive care, wilderness medical operations often exceed that time restraint before dispatch or its equivalent is notified. In most settings, prehospital time parameters are lengthened, including dispatch time, response time, scene time, and evacuation time. Some systems shorten response and evacuation time by the use of helicopters, but total time to definitive care is often still lengthened. This delay in care and prolonged length of care exposes providers to injuries and complications that are not common to the traditional prehospital provider. Medical entities such as sepsis, compartment syndrome, and crush syndrome are more likely to be encountered because of delays from definitive care. These differences force traditional prehospital providers to have a much deeper understanding of physiology, pathophysiology, and expected complications from various injuries and illnesses. Wilderness medical providers must also have mechanisms in place to address nutrition, hydration, and elimination while caring for and evacuating patients. The delay to definitive care also demands that providers are more astute in their physical diagnosis skills and can provide care above and beyond traditional prehospital protocols, in effect bringing definitive care to the patient in the wilderness. At present, many wilderness EMT curricula consist of expanded care protocols, including prehospital c-spine clearance, reduction of specific dislocations, advanced wound care techniques, and calling codes in the prehospital setting [4,5]. As the field of wilderness medicine develops and practitioners become better trained and more adept in necessary skill s and physicians become increasingly involved with wilderness EMS systems, even more advanced protocols might become commonplace. Just as time is a precious commodity in wilderness medicine, resources are also a major factor in many wilderness medical settings. Without the convenience of an emergency room, clinic, or even an ambulance, wilderness medical providers are often left to the few supplies they have handy and their improvisation skills. Even the expedition medical provider is often left with a lack of electricity, heating sources, and limited medications or supplies. The search and rescue provider and the ‘‘bystander’’ are even more constrained by the items they can physically carry and often must improvise various medical items when caring for patients [14] (Box 2). Because of the lack of diagnostic equipment, in-field practitioners of wilderness medicine must rely solely on their clinical judgment. Without the modern
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Box 2. Items for caring for wilderness patients Improvised airway management a. Improvised basic airway management techniques b. Improvised advanced/surgical airway techniques Improvised splinting techniques a. Spinal management b. Femur traction devices c. Slings d. Long bone splints e. Knee immobilizers Improvised litters and transportation a. One and two rescuer carries b. Rope litters c. Blanket litters d. Jacket litters e. Pack litters f. Ski pole/paddle litters g. Improvised sleds Improvised wound care a. Irrigation devices b. Improvised closure techniques Improvised pleural decompression of tension pneumothorax Improvised ring removal Improvised eye glasses
conveniences of traditional medicine, providers are forced to improvise, using any available resources. Thus, the skills of creativeness and inventiveness are paramount when practicing wilderness medicine. Medical resources that are present should be multipurpose with a variety of uses. In the field, ‘‘nonmedical’’ equipment is often adapted for medical use and many times the most important supplies to wilderness medical providers are ‘‘nonmedical’’ in nature, such as duct tape, a knife, or webbing. Resource limitations are even further realized in incidents that involve multiple patients; when already strained assets are spread between two or more injured parties. Resource identification, allocation, and distribution become major issues for groups providing medical care for multiple patients. The environment plays a tremendous role in wilderness medicine and impacts all involved and their medical and rescue equipment. Common to traditional first responder, EMT, and paramedic curricula is the concept of
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‘‘scene safety’’ (ie, individual and team safety is paramount when encountering a patient). So important is rescuer safety that it often preempts the ‘‘A, B, C’s’’ in prehospital care, with the understanding that only after adequate provisions for safety can patient care begin. Physicians are perhaps least well trained to consider scene safety, in part because of the familiar and secure environment in which they normally practice; however, the field of wilderness medicine pushes this concept to extremes, forcing wilderness medical providers to account not only for the obvious, primary threat that caused the patient’s condition but also for secondary threats to all on-scene personnel such as hypothermia, dehydration, altitude, overexertion, and fatigue. Just as important are the myriad unforeseen threats posed to a rescue team, threats caused by terrain, incoming weather, and so forth. Furthermore, patients encountered in the wilderness must be approached with the knowledge of potential environmental effects. For example, hypothermia, a common complication of urban and rural trauma and nearly ubiquitous injury in wilderness settings, must be considered in most patients, even those presenting in seasons or environments not commonly thought of as inducing hypothermia. The environment can impact health care providers’ interventions on patients. For instance, a continued drop of body temperature is commonly seen if rescuers do not anticipate and offset resuscitation hypothermia. Equally important are the environmental effects on the rescuer’s medical and rescue equipment. Cooling of IV fluids, freezing of temperature-sensitive medications, and degradation of ultraviolet (UV)-, water-, or temperature-susceptible equipment must be considered and countered. One of the major challenges in wilderness medicine is evacuation. There are many facets of evacuation in the wilderness, including rescue, groundbased evacuation, and aeromedical evacuation. Traditionally, rescue has been defined as a ‘‘transportation emergency,’’ requiring removal of a patient from a hazardous to a nonhazardous environment. In these settings rescue becomes isolated from medical care. For example, in many urban-based EMS systems, fire services perform extrication or rescue (high angle, swift water, fire, vehicular, and so forth) and deliver the patient to EMS providers who, in turn, provide medical care. With the exception of basic skills, the provision of medical care suffers in this model. In the wilderness, multiple rescue situations also occur, from high- to low-angle rope rescue, avalanche rescue, crevasse rescue, confined space rescue, and swift water rescue. Given already limited recourses and person power, provision of medical care and rescue often overlap. This model offers patients prompt and ongoing medical care during a rescue operation. With this in mind, wilderness medical providers must be trained to at least a minimum awareness level in fields of rescue appropriate to their setting. In many phases of rescue’s evolution, medical care is difficult or even impossible; however, dual-trained providers commonly find innovative means to deliver care. Even more common, evacuation difficulties arise when rescuers are forced to perform
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ground-based evacuation. Ground-based evacuations might involve mechanized vehicles, but in many instances the environment precludes vehicular transport, leaving search and rescue teams to carry victims out of the backcountry. In addition to being cumbersome, this practice is potentially dangerous to the providers [6], setting them up for various injuries, including lower extremity injuries and back injuries and exposing rescuers to possibly dangerous terrain. Route choice, route clearance, and evacuation safety are so paramount that many search and rescue providers dedicate members to these tasks to ensure team safety. Along with provider safety, patient security and comfort must also be considered. Many litter systems and carrying techniques limit a patient’s ability to protect themselves from falling debris, precipitation, and UV light; therefore eye protection must be included in patient packaging. Nausea and vomiting are common in patients carried for long distances in litters. Litter evacuations of any type, including aeromedical evacuations, pose potential dangers to patients in the form of falls during low-angle or high-angle operations or hauls. Ground-based, person-powered evacuations also lengthen already delayed time to definitive care and are person-power intensive, requiring at least six people to carry a litter one quarter of a mile over minimally rigorous terrain [7]. Even more carriers are required for longer evacuations over rough terrain. The personnel available to a patient in wilderness medicine settings are often different from those in traditional medicine. Many European countries, including Switzerland, have robust wilderness EMS programs that offer patients aeromedical services with on-board physicians or paramedics [8]. The United States system is much different, with aeromedical evacuation the exception rather than the rule. The United States in general has few physicians practicing in-field or prehospital medicine, and this trend follows in wilderness medical settings. Most care offered in the wilderness is not provided by advanced life-saving (ALS or paramedic) providers, and in many systems the most common medical providers are trained to the EMT level at most [9]. While the utility of traditional, urban ALS skills (ie, ACLS medications) are debatable in true wilderness settings, the fact remains that the majority of wilderness medical providers offer less elaborate medical skills. One study from Portland, Oregon describing a specialized ALS team called the Reach and Treat Team suggests that, besides airway management, the major value of offering advanced level providers rested in their abilities to offer pain management, antiemetics, and delivery of advanced medications (eg, mannitol for head injuries) [10]. This study suggests that advanced medical care and advanced medical skills have a potential mortality benefit and a definite morbidity benefit to patients encountered in the wilderness. Even in systems that provide ALS-trained practitioners or physicians, these caregivers are frequently asked to provide a level of care uncommon to their practice or to provide much more comprehensive care. For instance, a physician encountering a patient in the wilderness might be asked to perform tasks and use skills that are commonly
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considered to be nursing skills (eg, medication dose calculations) or EMS skills (eg, patient access and transport). Offering care across skill sets might be just as challenging to physicians as providing expanded care is to EMTs, paramedics, or nurses. Wilderness medicine thus acts as a bridge, linking hospital-based providers to prehospital-based providers by forcing physicians and nurses to learn prehospital skills and specific rescue techniques and forcing prehospital providers to learn expanded protocols and prolonged patient care skills. Finally, preparedness becomes paramount in wilderness medicine. Preparedness begins with prevention—having the proper skills to perform a particular activity, knowledge of the route chosen, the route condition, and current and forecasted weather. These challenges of wilderness medicine suggest a difficult arena in which to practice medical skills, so injuries and illnesses should be avoided at all costs. For the health care provider practicing in the wilderness, preparedness includes possessing the physical skills and prowess to practice in a challenging environment, the proper training and equipment to enter the chosen setting, and the mental and emotional stamina to engage in potentially long-term care of challenging patients who have limited resources. Many providers struggle with the limitations of wilderness medicine, a reality that requires patience and understanding. Proper training is paramount; the practice of wilderness medicine requires a distinctive assimilation of medical skills with operational, survival, and rescue skills. Despite these challenges, this integration of skills appeals to many providers and creates an exciting environment in which to practice medicine. Injury and illness occurrence in the wilderness: wilderness medical epidemiology Another important consideration when approaching the field of wilderness medicine is the frequency and type of injuries that occur in the outdoors. A number of studies have examined the incidence of injuries or illnesses in the wilderness; however, many of these studies tend to focus on specific activities, particular locations, or single populations. Perhaps the largest epidemiologic study to date was performed by Gentile et al in 1992 [11]. The authors examined the incidence of injury or illness in students of the National Outdoor Leadership School over a 5-year period (1984–1989). This study included 10,977 participants and more than 358,210 person-days of exposure in various environments, including such diverse locations as Denali National Park and the Gila Wilderness. Participants were involved in many activities including backpacking, Nordic skiing, whitewater paddling, sea kayaking/sailing, caving, horse packing, rock climbing, expedition mountaineering, mountaineering, and mountaineering on snow/ice. The overall injury rate for this population was 2.3 per 1000 person-days of exposure, whereas the illness rate was 1.5 per 1000 person-days of exposure.
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Extremity sprains/strains (53%) and soft tissue injuries (27%) made up the majority of injuries (80%) in this study. The most common injury location was the lower extremity, accounting for 56% of all injuries with 64% of all sprains and strains involving the ankle and the knee. The majority of illnesses (60%) were caused by viral illnesses or diarrhea. Other illnesses included dermatitis (4%), mountain sickness (4%), gynecologic conditions (3%), hypothermia (3%), ear infections (3%), dental conditions (3%), urinary tract infections (2%), and allergic reactions (2%). Backpacking accounted for the majority of exposure days (43%) and injuries (44.1%); however, the injury rate was highest in whitewater paddling (6.1 per 1000 person-days) and Nordic skiing (3.7 per 1000 person-days). Mountaineering, rock climbing, and ice/snow climbing, which are regarded as high-risk activities, had low injury rates in this study, all less than that of backpacking. One major criticism of this study is that it addressed a predominately younger population. Of the 10,977 participants, 8094 were students and 86.9% of the students were under the age of 30 years. While boasting large numbers, diverse environments, and varying activities, this study likely does not represent the population participating in wilderness activities and in particular does not shine light on the true incidence and type of medical illnesses occurring in the wilderness. The general findings of this study were confirmed by Montalvo et al in a 1998 study examining injuries, illnesses, and mortality in national parks located in California [12]. These authors retrospectively examined fatal injuries in eight parks and nonfatal injuries in seven parks over a 3-year period. Of the 1708 injuries that occurred, musculoskeletal injury and soft tissue injury accounted for 70%. The lower extremities accounted for 38.5% of all injury locations followed by the upper extremities (27.1%), the head and neck (26.6%), and the torso (7.9%). In this study 25.6% of all incidents were caused by illnesses. Pain (1.9%), dizziness (1.8%), shortness of breath (1.8%), vomiting (1.6%), and dehydration/heat stroke (1.5%) accounted for the top five illnesses. The authors did not speculate on the high incidence of medically related events. Possible causes include an aging population in the United States and increased access to and interest in wilderness areas, especially in national parks. Of interest, cardiac death accounted for the most common cause of mortality, followed by drowning, falls (50–800 feet), motor vehicle accidents, and plane crashes. Another study published by Goodman et al in 2001 examined mortality in wilderness areas of Pima County, Arizona over the 13 years between 1980 and 1992 [13]. As with Montalvo’s study, falls were a causative factor in a large percentage of mortalities. Of the 100 deaths over the 13-year period, falls or falls with associated immersion/submersion/drowning accounted for 35% of all deaths. Technical rock climbing accounted for only one of these fatal falls. Alcohol might have played a role in the deaths associated with falls; 75% of this population was found to have positive alcohol levels on forensic examination. The most common injuries in this population were head and
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neck injuries. Suicides, drowning, and homicide rounded out the top four causes of death. Medical causes of mortality were not as prevalent in this study, accounting for 12% of deaths, with heat accounting for the majority followed by cardiac disease and diabetes. The authors of this study examined the causes of mortality and suggested that the majority of deaths occurred immediately after the accident or before the arrival of search and rescue teams. They therefore postulated that resources should be dedicated to prevention and public awareness rather than search and rescue in efforts to reduce mortality. In contrast to this belief, Schmidt et al published a study examining the Reach and Treat Team, a group of urban paramedics dual trained in wilderness medicine that responds to wilderness emergencies in the Portland, Oregon area [10]. In an innovative effort to reduce issues of skills depletion, the paramedics’ primary responsibility is to a larger urban area. The team responds from this area for the estimated 25 wilderness calls per year. The study retrospectively examined the experience of this team over a 5-year period. Confirming earlier studies, this study found that extremity injuries accounted for 50.9% of the 114 reported injuries with head injuries and hypothermia accounting for 15.8% and 13.2%, respectively. Ninety percent of patients received advanced level care, including 52 patients receiving intravenous lines, 40 receiving intravenous fluids, 24 receiving pain control (morphine), and 13 receiving antiemetics (droperidol). Eight patients were intubated, two patients received mannitol for closed head injuries, and two patients received CPR. While admitting that the clinical relevance of these advanced skills was difficult to determine, the authors found that times to intubation were reduced by 1.5 hours on average. While probability of survival data suggest that this patient population could have been expected to survive in normal prehospital conditions, it is uncertain if those same rules can be applied to wilderness settings. Even without mortality benefits, the Reach and Treat Team could affect morbidity by providing on-scene pain control and antiemetics during transport. Perhaps the major benefits of advanced medical care on scene for the majority of patients in wilderness settings is in the provision of care that reduces morbidity, not mortality. The aforementioned studies reflect the large advances made in the past decades to understand the unique and dynamic arena of wilderness medicine and the work necessary to further delineate this burgeoning field of medicine. For instance, major questions remain regarding the proper provisions of care to patients in the wilderness. Are Goodman et al correct to suggest that any excess resources delivered to search and rescue should be diverted to public education and prevention? Is Schmidt’s model of advanced medical skills the correct paradigm? What becomes clear from these studies is that the preponderance of emergencies occurring in the wilderness are not caused by exotic events (animal attacks, lightning, and so forth) but rather to more common events such as walking, hiking, skiing, and so forth. The most frequent injuries that befall this population of
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patients are caused by trauma, infections, and complications of underlying medical conditions, followed by the events that are typically thought of as ‘‘wilderness injuries.’’ The challenge for wilderness medicine and its practitioners is to model a system of care that allows for the treatment of these patients in a uniquely austere and dynamic environment. One overall correct model is difficult to speculate on, but it would likely involve a combination of the prototypes offered by Goodman and Schmidt and would involve public health measures such as prevention and education and a more robust emergent provision of care. This care must involve advanced medical protocols different from the standard urban or rural EMS setting. The challenges of wilderness medicine include addressing issues such as delayed time to definitive care with potential for complications or progression of the underlying injury or illness. Only through an assessment of local wilderness medical threats and local wilderness EMS needs can trained physicians, wilderness or Search and Rescue specialists, EMS providers, and appropriate public safety officials begin to address these issues.
Summary Wilderness medicine represents a unique field of medicine, combining elements from traditional medical specialties (especially emergency medicine and primary care medicine) with environmental injuries and illnesses and various rescue and EMS skills. Regardless of the arena in which they operate, the practitioners of wilderness medicine are exposed to various challenges including prolonged patient care, resource management, environmental stressors, evacuation difficulties, personnel management, and preparedness/prevention challenges. As the field of wilderness medicine has developed it has become clear that emergency incidents in the wilderness are in large part caused by trauma, infections, and complications of chronic disease followed by injuries or illnesses caused by environmental factors. One of the major challenges remaining for wilderness medicine in the United States is striving to determine the correct provision of care for patients in the wilderness.
Further readings Bowman WD. The development and current status of wilderness prehospital emergency care in the United States. J Wilderness Med 1990;1:93–102. Federiuk C. Clinical update on emergency medical care in the wilderness. Wilderness Environ Med 1999;10:20–4. Kaufman T, Knoop R, Webster T, et al. The Parkmedic Program: prehospital care in the national parks. Ann Emerg Med 1981;10(3):156–60. Paton BC. Health, safety and risk in outward bound. J Wilderness Med 1992;3:128–44. Peterson E, Snider W, Fahrenwald R. A model for wilderness medicine education in a family practice residency. Wilderness Environ Med 2002;13:266–8.
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Townes DA. Wilderness medicine. Primary Care: Clinics in Office Practice 2002;29(4):1027–48. Williamson J. Accidents in North American mountaineering—2002. American Alpine Club: Golden, CO; 2002.
References [1] Auerbach P. Preface. In: Wilderness medicine. St. Louis (MO): Paul Auerbach, Mosby; 2001. p. xix. [2] Bowman W. Perspectives on being a wilderness physician: is wilderness medicine more than a special body of knowledge? Wilderness Environ Med 2001;12:165–7. [3] Backer HD. What is wilderness medicine? Wilderness Environ Med 1995;6:3–10. [4] Wilderness emergency medical technician upgrade. Available at: http://www.wildmed.com/ course_fact_sheets/wemt_facts.html. Accessed June 24, 2003. [5] Course descriptions—wilderness EMT. Available at: http://www.mountainaid.com/ frame_0.html. Accessed June 24, 2003. [6] Iserson KV. Injuries in search and rescue volunteers—a 30-year experience. West J Med 1989;151:352–3. [7] Cooper DC, Messenger J, Mier T, et al. Litters and carries. In: Wilderness medicine. St. Louis (MO): Paul Auerbach, Mosby; 2001. p. 633. [8] Durrer B. Rescue operations in the Swiss Alps in 1990 and 1991. J Wilderness Med 1993;4: 363–73. [9] Johnson J, Maertins M, Shalit M, et al. Wilderness emergency medical systems: the experiences at Sequoia and Kings Canyon National Parks. Am J Emerg Med 1991;9(3): 211–6. [10] Schmidt T, et al. Advanced life support in the wilderness: 5-year experience of the Reach and Treat Team. Wilderness Environ Med 1996;3:208–15. [11] Gentile D, Morris J, Schimelpfenig T, et al. Wilderness. Ann Emerg Med 1992;21(7): 853–61. [12] Montalvo R, Wingard DL, Bracker M, et al. Morbidity and mortality in the wilderness. West J Med 1998;168(4):248–54. [13] Goodman T, Iserson K, Strich H, et al. Wilderness mortalities: a 13-year experience. Ann Emerg Med 2001;37(3):279–83. [14] Weiss E, Donner H. Wilderness improvisation. In: Wilderness medicine. St. Louis (MO): Paul Auerbach, Mosby; 2001. p. 466–94.
An introduction to wilderness medicine J. Matthew Sholl, MDa,*, Edward P. Curcio III, MDb a
Department of Emergency Medicine, Maine Medical Center, 22 Bramhall Street, Portland, ME 04012, USA b Department of Emergency Medicine, Mount Auburn Hospital, 330 Mount Auburn Street, Cambridge, MA 02138, USA
Outdoor and wilderness activities are the fastest growing recreational activities in the United States [1]. Newer activities such as mountain biking, snowboarding, and sea kayaking have become extremely popular in the past decades, whereas older activities such as mountaineering, rock climbing and ice climbing have recently found a new birth and are enjoyed by many newcomers each year. Some of these pursuits have become increasingly dangerous and ‘‘extreme,’’ with participants pushing the boundaries of safety and security. As more individuals are becoming ever more involved in outdoor activities, there is an increasing need for care and counseling in traditional and nontraditional settings. In response to this increase in activity, and in an attempt to provide assistance to those living and performing at the extremes of human experience, the dynamic and evolving field of wilderness medicine has developed; however, just as disparate as the various environments that make up the wilderness are the various understandings of the true definition of wilderness medicine. The core content of wilderness medicine is perhaps an easier question and is made up of the various topics contained in this text and others that are not included (Box 1). Combined, these topics attempt to cover the dissimilar realms that make up the wilderness and wilderness medicine. This article examines wilderness medicine in its current state and attempts to define this developing field of medicine.
* Corresponding author. E-mail address: [email protected] (J.M. Sholl). 0733-8627/04/$ - see front matter Ó 2004 Elsevier Inc. All rights reserved. doi:10.1016/j.emc.2004.01.001
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Box 1. Areas of wilderness medicine Trauma, including orthopedic care Altitude Animal bites Arachnid envenomations Snake envenomations Cold injuries, including frostbite and hypothermia Heat illnesses Toxic plant exposures Parasitism and tropical medicine Travel medicine Emergency veterinary care Search and rescue Diving accidents and dysbarism Submersion and immersion injuries White water medicine and rescue Open water medicine and survival Improvisation Aeromedical rescue Avalanche and crevasse rescue Survival and wilderness navigation Natural disaster management Wilderness management of chronic medical diseases Emergency medical services (EMS) and wilderness EMS Education
Defining wilderness and wilderness medicine Perhaps the natural place to begin when defining wilderness medicine is to first examine the definition of wilderness. The term ‘‘wilderness’’ might have different meanings for different people. A traditional definition of wilderness includes ‘‘(a) a tract or region uncultivated and uninhabited by human beings, and (b) an area essentially undisturbed by human activity together with its naturally developed life community’’ [2]. Many individuals define wilderness in terms of topographical or regional terms, such as a favorite trail or camping site, a particular mountain, a National or State Park, a local preserve, or an unnamed backcountry area. Others are more specific and define wilderness in part by the activities that bring them to the area (eg, rock or ice climbing, mountaineering, kayaking, caving, or backcountry skiing). In an attempt to draw together these varying descriptions, this article borrows from the wilderness EMS arena and begins by defining wilderness in terms of time from definitive care, typically 1 to 2 hours from hospital-based care. While not focusing on the
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geographical particulars or physical activities involved, this definition remains inclusive and might involve a multitude of environments and activities. When specifically examining medical care, this definition embraces many fields of medicine that are traditionally considered to be dissimilar, including wilderness medicine, tactical/military medicine, and disaster medicine. Closer examination, however, reveals that these fields share four core components: (1) their austere nature; (2) roots in traditional prehospital medicine with, at times, necessity for expanded care protocols or expanded patient care; (3) integration of medical and rescue skills; and (4) inherent threats encountered in each environment (Figure 1). Disasters commonly destroy or overwhelm a community’s infrastructure and stress the local medical providers, causing a unique ‘‘wilderness’’ in an otherwise urban setting. Tactical medical providers work under obvious threat and are frequently trained in expanded prehospital protocols. These providers might also find themselves operating in an urban or suburban setting but remain distant from definitive care because of ongoing threats to themselves or their team. Military medicine and wilderness medicine share common roots, and the experiences of in-field trauma management in North Korea and Vietnam helped develop protocols and practices for civilian applications. Using the previously mentioned definition of ‘‘wilderness’’ might be inclusive enough to include some traditional, rural EMS systems as well. While a good starting point, time from definitive care alone cannot capture the essence of wilderness medicine; time-based boundaries might well define an area of wilderness but lack in ability to define wilderness medicine specifically. One argument suggests that the true definition of wilderness medicine must involve consideration of the injury location. For instance, a climber who has high altitude pulmonary edema at Camp Muir, an Appalachian Trail through hiker with an injured ankle, and a near-drowning victim on the Colorado river are all obvious ‘‘wilderness medicine’’ patients, purely based on the physical location in which their injuries occurred. A second aspect of this definition involves the activity that brought the patient to said location: hiking, climbing, whitewater or sea kayaking, skiing, hunting, and
Each apparently different field of medicine shares in common their austere nature, with overwhelmedresources, threatening environment, and occasional delay to definitive care. The quintessential nature of each lays in the pre-hospital provision of care and at times demands prolonged patient care, expanded care protocols, and integration of medicine and rescue.
Wilderness
Tactical/Military
Disaster
Fig. 1. Overlapping realms of wilderness tactical/military and disaster medicine.
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so forth. Difficulty comes, however, in different individuals’ appreciation of what defines a ‘‘wilderness’’ location. Natural parks or uninhabited areas might be accepted as wilderness by most, whereas many would debate whether or not ski slopes, with established ski patrols and in proximity to urban or rural settings, can be defined as wilderness. Recreational and resort communities, which often border rugged wilderness areas, further blur the boundaries of wilderness. Still a third definition of wilderness medicine would stress the injury itself. Hypothermia, whether encountered on the summit of a mountain or in the back alleys of an urban city, is ‘‘wilderness medicine,’’ an injury resulting from the direct interaction between humans and their environment. Other obvious additions based on this definition would include mammalian and arthropod bites, envenomations, heat injuries, and altitude illnesses, to name a few. Many of these instances are more common in urban or suburban settings (hypothermia, heat illness, lightning injuries, and submersion) [3]. All would agree that the heart and soul of wilderness medicine includes a sense of connection with and stewardship for the wilderness. Individuals engaging in any wilderness activity for recreational or professional (including medical) causes usually share a deep bond with the natural world. The field of wilderness medicine allows for many to marry their professional occupation and its curiosities with their extracurricular passions. The proper definition of wilderness medicine must involve all these concepts: location where the injury occurred, time to definitive care, and type of injury, with particular attention toward those injuries that are directly related to human interaction with the environment. After examining these factors, one begins to discover the essence of wilderness medicine: injuries and illnesses caused by the interaction between humans and their natural environment occurring in potentially austere and threatening environments. The range and arenas of wilderness medicine can be equally incongruent. By virtue of its varied scope, wilderness medicine cannot be owned by any one traditional field of medicine. Indeed, wilderness medicine shares similarities with emergency medicine, primary care and internal medicine, occupational medicine, sports medicine, military medicine, infectious disease, pulmonary medicine, trauma surgery, and orthopedics, to name a few. Perhaps broader-based specialties are best equipped to address the breadth of wilderness medical injuries and illnesses, but even so, these providers must at times consult upon the expertise of their specialized colleagues, including those proficient in nonmedical skills such as wilderness guides and rescue personnel. While many wilderness medicine patients inevitably present to traditional centers of care, the essence and roots of wilderness medicine rest in the out-of-hospital delivery of care or in-field care. Wilderness medical providers who offer prehospital care might find themselves in tremendously different arenas. For example, the expedition medical provider or ‘‘trip doctor’’ comes prepared with full knowledge of the environment he or she is entering, and in many cases this provider has the
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ability to obtain past history of those being cared for and has time to adequately prepare for expected medical ailments. These providers are limited only by the weight they can carry and their imagination when preparing medical threat assessments. Meanwhile, the search and rescue provider is more akin to the traditional emergency medical provider and has limited knowledge of those being cared for and incomplete knowledge of the setting in which the patient can be found. These providers must carry a broad array of medical and rescue supplies while working under less than opportune circumstances but have at their assistance the local wilderness EMS system of care. Finally, wilderness medicine can occur to ‘‘innocent bystanders,’’ physicians, nurses, EMS providers, or laypersons not expecting to come across a trip mate or stranger who is injured or ill. It is this unforeseen wilderness medical provider who is perhaps pushed most to his or her limits, forced to provide care with limited resources and accessing a sometimes-difficult system of care. All of these providers must struggle against the factors that make wilderness medicine so challenging—critical elements that, along with time to care, location of injury and injury type, help define wilderness medicine as a unique and dynamic field: resource limitation and allocation; environmental impact on the patient, rescuer, and resources; evacuation difficulties; limited personnel providing care; and emotional, mental and physical preparedness necessary to provide care in the wilderness. Challenges of wilderness medicine It is perhaps easiest to examine these factors in a case-based setting while contrasting with common or traditional care. Patient #1, a 40-year-old man, falls 12 feet down a flight of stairs while at his Beacon Hill home in Boston, while patient #2, again a 40-year-old man, sustains a 12-foot leader fall while ice climbing Pinnacle gully on the flanks of Mount Washington in New Hampshire in February. In the urban environment, a simple phone call to 911 begins a cascade of events meant to maximize patient care. The phone call goes to a central agency, which then dispatches the closest prehospital provider. In Boston, the fire department and EMS race to the scene. Arrival time occurs in minutes, for finding the patient is just a matter of finding an address. Equipment is brought a few feet from the truck into the patient’s home, the only crux on the approach is perhaps a flight of stairs. On-scene care is managed inside the house or ambulance, far away from the threat of inclement weather. Patient #1 is found at the bottom of the stairs, unable to get up because of a fractured femur. Care starts with a rapid patient assessment, stabilization of the fractured femur, and administration of intravenous (IV) fluids. A cervical collar is left in the truck by mistake and a medic runs back to the truck to get the correct piece of equipment. The patient is stabilized and quickly placed on a backboard to ease extrication. Whisked from his home, he is placed quickly in a warm and dry truck as the
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medics contact the nearest hospital to alert them of their arrival. An emergency medicine physician trained in the latest Advanced Trauma Life Support (ATLS) and prehospital protocols provides medical control, and within minutes the patient is at the hospital receiving definitive care. In the ice gully on Mount Washington, patient #2 moans in response to the fall. Still attached to the rope, his climbing partner strains to set up a system to free himself. Minutes pass rapidly as he finally extricates himself from the rope system and comes to his friend’s aid. He approaches carefully, ever alert for avalanche danger and falling ice from above. He quickly realizes that his friend is gravely injured by the strange angle his leg juts from his harness. He places a tarp down and covers his injured partner with a sleeping bag, for he knows that the fractured leg is not the only threat; the cold of the mountain starts to slowly impact his friend’s health. He attempts to use his cell phone to contact help, but it does not function in the cold air, far away from any cell tower. He makes a tough decision and decides to go for help. The closest ranger station is 3 hours away, and he quickly descends the mountain. When he arrives at the ranger station, a call goes out to the local search and rescue team, a mix of volunteers who have various medical and rescue experience and who can break free from their jobs and family and arrive at the base of Mount Washington within 1 hour. As they gear up for the 4-hour approach, a splint bag is left inadvertently behind. They start up the mountain, single file, their headlights shining on the fresh snow, which has started to fall. Tired, they finally arrive on scene 8 hours after the initial injury occurred. As they begin to care for patient #2, they are challenged by cloaking darkness, the threat of falling ice, and the constant cold. An IV is attempted, but frigid fingers miss the vein, a second attempt is successful, and a bag of normal saline, kept warm inside a rescuer’s coat, is slowly infused. As they attempt to stabilize the fractured femur, they discover that the wayward bag is missing. A discussion occurs. To retrieve the bag is a 7-hour endeavor, so a decision is made to improvise a splint. Realizing that an exit at night is impossible, they set up tents, make dinner, and set up a watch system. Morning slowly arrives as their patient begins to slip in and out of consciousness; the stress of the fractured femur coupled with the cold has started to take its toll. No more IV fluid is available, and shock has set in. The rescue team would like guidance through medical control, but communication remains impossible. At daybreak, the rescue team begins extrication. First preparing the patient for litter travel with a hypothermia wrap, they place him in the litter and begin the hike out. The 3-hour hike takes 6 hours while carrying the litter, and the patient is comatose upon arrival the ranger station. It is here that our wilderness patient first encounters the traditional medical system. A heated ambulance awaits him at the ranger station, where fresh emergency medicine technicians (EMTs) begin to work on the patient. Warmed IV fluids are started and he is placed carefully in the ambulance and rushed to the nearest hospital. His situation
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is guarded upon arrival, but he unfortunately passes away during his extended hospital stay, a victim of his fractured femur, hypothermia, and prolonged extrication. These two vignettes are representative of many wilderness medical systems and shine light on the critical features of wilderness medicine. Time is a decisive element in wilderness medicine, and in some instances it helps to define an event as ‘‘wilderness.’’ Patient #2’s scenario is not uncommon in many parts of the world. While urban and even rural settings operate within the modern time restraints of the ‘‘golden hour’’ to definitive care, wilderness medical operations often exceed that time restraint before dispatch or its equivalent is notified. In most settings, prehospital time parameters are lengthened, including dispatch time, response time, scene time, and evacuation time. Some systems shorten response and evacuation time by the use of helicopters, but total time to definitive care is often still lengthened. This delay in care and prolonged length of care exposes providers to injuries and complications that are not common to the traditional prehospital provider. Medical entities such as sepsis, compartment syndrome, and crush syndrome are more likely to be encountered because of delays from definitive care. These differences force traditional prehospital providers to have a much deeper understanding of physiology, pathophysiology, and expected complications from various injuries and illnesses. Wilderness medical providers must also have mechanisms in place to address nutrition, hydration, and elimination while caring for and evacuating patients. The delay to definitive care also demands that providers are more astute in their physical diagnosis skills and can provide care above and beyond traditional prehospital protocols, in effect bringing definitive care to the patient in the wilderness. At present, many wilderness EMT curricula consist of expanded care protocols, including prehospital c-spine clearance, reduction of specific dislocations, advanced wound care techniques, and calling codes in the prehospital setting [4,5]. As the field of wilderness medicine develops and practitioners become better trained and more adept in necessary skill s and physicians become increasingly involved with wilderness EMS systems, even more advanced protocols might become commonplace. Just as time is a precious commodity in wilderness medicine, resources are also a major factor in many wilderness medical settings. Without the convenience of an emergency room, clinic, or even an ambulance, wilderness medical providers are often left to the few supplies they have handy and their improvisation skills. Even the expedition medical provider is often left with a lack of electricity, heating sources, and limited medications or supplies. The search and rescue provider and the ‘‘bystander’’ are even more constrained by the items they can physically carry and often must improvise various medical items when caring for patients [14] (Box 2). Because of the lack of diagnostic equipment, in-field practitioners of wilderness medicine must rely solely on their clinical judgment. Without the modern
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Box 2. Items for caring for wilderness patients Improvised airway management a. Improvised basic airway management techniques b. Improvised advanced/surgical airway techniques Improvised splinting techniques a. Spinal management b. Femur traction devices c. Slings d. Long bone splints e. Knee immobilizers Improvised litters and transportation a. One and two rescuer carries b. Rope litters c. Blanket litters d. Jacket litters e. Pack litters f. Ski pole/paddle litters g. Improvised sleds Improvised wound care a. Irrigation devices b. Improvised closure techniques Improvised pleural decompression of tension pneumothorax Improvised ring removal Improvised eye glasses
conveniences of traditional medicine, providers are forced to improvise, using any available resources. Thus, the skills of creativeness and inventiveness are paramount when practicing wilderness medicine. Medical resources that are present should be multipurpose with a variety of uses. In the field, ‘‘nonmedical’’ equipment is often adapted for medical use and many times the most important supplies to wilderness medical providers are ‘‘nonmedical’’ in nature, such as duct tape, a knife, or webbing. Resource limitations are even further realized in incidents that involve multiple patients; when already strained assets are spread between two or more injured parties. Resource identification, allocation, and distribution become major issues for groups providing medical care for multiple patients. The environment plays a tremendous role in wilderness medicine and impacts all involved and their medical and rescue equipment. Common to traditional first responder, EMT, and paramedic curricula is the concept of
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‘‘scene safety’’ (ie, individual and team safety is paramount when encountering a patient). So important is rescuer safety that it often preempts the ‘‘A, B, C’s’’ in prehospital care, with the understanding that only after adequate provisions for safety can patient care begin. Physicians are perhaps least well trained to consider scene safety, in part because of the familiar and secure environment in which they normally practice; however, the field of wilderness medicine pushes this concept to extremes, forcing wilderness medical providers to account not only for the obvious, primary threat that caused the patient’s condition but also for secondary threats to all on-scene personnel such as hypothermia, dehydration, altitude, overexertion, and fatigue. Just as important are the myriad unforeseen threats posed to a rescue team, threats caused by terrain, incoming weather, and so forth. Furthermore, patients encountered in the wilderness must be approached with the knowledge of potential environmental effects. For example, hypothermia, a common complication of urban and rural trauma and nearly ubiquitous injury in wilderness settings, must be considered in most patients, even those presenting in seasons or environments not commonly thought of as inducing hypothermia. The environment can impact health care providers’ interventions on patients. For instance, a continued drop of body temperature is commonly seen if rescuers do not anticipate and offset resuscitation hypothermia. Equally important are the environmental effects on the rescuer’s medical and rescue equipment. Cooling of IV fluids, freezing of temperature-sensitive medications, and degradation of ultraviolet (UV)-, water-, or temperature-susceptible equipment must be considered and countered. One of the major challenges in wilderness medicine is evacuation. There are many facets of evacuation in the wilderness, including rescue, groundbased evacuation, and aeromedical evacuation. Traditionally, rescue has been defined as a ‘‘transportation emergency,’’ requiring removal of a patient from a hazardous to a nonhazardous environment. In these settings rescue becomes isolated from medical care. For example, in many urban-based EMS systems, fire services perform extrication or rescue (high angle, swift water, fire, vehicular, and so forth) and deliver the patient to EMS providers who, in turn, provide medical care. With the exception of basic skills, the provision of medical care suffers in this model. In the wilderness, multiple rescue situations also occur, from high- to low-angle rope rescue, avalanche rescue, crevasse rescue, confined space rescue, and swift water rescue. Given already limited recourses and person power, provision of medical care and rescue often overlap. This model offers patients prompt and ongoing medical care during a rescue operation. With this in mind, wilderness medical providers must be trained to at least a minimum awareness level in fields of rescue appropriate to their setting. In many phases of rescue’s evolution, medical care is difficult or even impossible; however, dual-trained providers commonly find innovative means to deliver care. Even more common, evacuation difficulties arise when rescuers are forced to perform
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ground-based evacuation. Ground-based evacuations might involve mechanized vehicles, but in many instances the environment precludes vehicular transport, leaving search and rescue teams to carry victims out of the backcountry. In addition to being cumbersome, this practice is potentially dangerous to the providers [6], setting them up for various injuries, including lower extremity injuries and back injuries and exposing rescuers to possibly dangerous terrain. Route choice, route clearance, and evacuation safety are so paramount that many search and rescue providers dedicate members to these tasks to ensure team safety. Along with provider safety, patient security and comfort must also be considered. Many litter systems and carrying techniques limit a patient’s ability to protect themselves from falling debris, precipitation, and UV light; therefore eye protection must be included in patient packaging. Nausea and vomiting are common in patients carried for long distances in litters. Litter evacuations of any type, including aeromedical evacuations, pose potential dangers to patients in the form of falls during low-angle or high-angle operations or hauls. Ground-based, person-powered evacuations also lengthen already delayed time to definitive care and are person-power intensive, requiring at least six people to carry a litter one quarter of a mile over minimally rigorous terrain [7]. Even more carriers are required for longer evacuations over rough terrain. The personnel available to a patient in wilderness medicine settings are often different from those in traditional medicine. Many European countries, including Switzerland, have robust wilderness EMS programs that offer patients aeromedical services with on-board physicians or paramedics [8]. The United States system is much different, with aeromedical evacuation the exception rather than the rule. The United States in general has few physicians practicing in-field or prehospital medicine, and this trend follows in wilderness medical settings. Most care offered in the wilderness is not provided by advanced life-saving (ALS or paramedic) providers, and in many systems the most common medical providers are trained to the EMT level at most [9]. While the utility of traditional, urban ALS skills (ie, ACLS medications) are debatable in true wilderness settings, the fact remains that the majority of wilderness medical providers offer less elaborate medical skills. One study from Portland, Oregon describing a specialized ALS team called the Reach and Treat Team suggests that, besides airway management, the major value of offering advanced level providers rested in their abilities to offer pain management, antiemetics, and delivery of advanced medications (eg, mannitol for head injuries) [10]. This study suggests that advanced medical care and advanced medical skills have a potential mortality benefit and a definite morbidity benefit to patients encountered in the wilderness. Even in systems that provide ALS-trained practitioners or physicians, these caregivers are frequently asked to provide a level of care uncommon to their practice or to provide much more comprehensive care. For instance, a physician encountering a patient in the wilderness might be asked to perform tasks and use skills that are commonly
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considered to be nursing skills (eg, medication dose calculations) or EMS skills (eg, patient access and transport). Offering care across skill sets might be just as challenging to physicians as providing expanded care is to EMTs, paramedics, or nurses. Wilderness medicine thus acts as a bridge, linking hospital-based providers to prehospital-based providers by forcing physicians and nurses to learn prehospital skills and specific rescue techniques and forcing prehospital providers to learn expanded protocols and prolonged patient care skills. Finally, preparedness becomes paramount in wilderness medicine. Preparedness begins with prevention—having the proper skills to perform a particular activity, knowledge of the route chosen, the route condition, and current and forecasted weather. These challenges of wilderness medicine suggest a difficult arena in which to practice medical skills, so injuries and illnesses should be avoided at all costs. For the health care provider practicing in the wilderness, preparedness includes possessing the physical skills and prowess to practice in a challenging environment, the proper training and equipment to enter the chosen setting, and the mental and emotional stamina to engage in potentially long-term care of challenging patients who have limited resources. Many providers struggle with the limitations of wilderness medicine, a reality that requires patience and understanding. Proper training is paramount; the practice of wilderness medicine requires a distinctive assimilation of medical skills with operational, survival, and rescue skills. Despite these challenges, this integration of skills appeals to many providers and creates an exciting environment in which to practice medicine. Injury and illness occurrence in the wilderness: wilderness medical epidemiology Another important consideration when approaching the field of wilderness medicine is the frequency and type of injuries that occur in the outdoors. A number of studies have examined the incidence of injuries or illnesses in the wilderness; however, many of these studies tend to focus on specific activities, particular locations, or single populations. Perhaps the largest epidemiologic study to date was performed by Gentile et al in 1992 [11]. The authors examined the incidence of injury or illness in students of the National Outdoor Leadership School over a 5-year period (1984–1989). This study included 10,977 participants and more than 358,210 person-days of exposure in various environments, including such diverse locations as Denali National Park and the Gila Wilderness. Participants were involved in many activities including backpacking, Nordic skiing, whitewater paddling, sea kayaking/sailing, caving, horse packing, rock climbing, expedition mountaineering, mountaineering, and mountaineering on snow/ice. The overall injury rate for this population was 2.3 per 1000 person-days of exposure, whereas the illness rate was 1.5 per 1000 person-days of exposure.
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Extremity sprains/strains (53%) and soft tissue injuries (27%) made up the majority of injuries (80%) in this study. The most common injury location was the lower extremity, accounting for 56% of all injuries with 64% of all sprains and strains involving the ankle and the knee. The majority of illnesses (60%) were caused by viral illnesses or diarrhea. Other illnesses included dermatitis (4%), mountain sickness (4%), gynecologic conditions (3%), hypothermia (3%), ear infections (3%), dental conditions (3%), urinary tract infections (2%), and allergic reactions (2%). Backpacking accounted for the majority of exposure days (43%) and injuries (44.1%); however, the injury rate was highest in whitewater paddling (6.1 per 1000 person-days) and Nordic skiing (3.7 per 1000 person-days). Mountaineering, rock climbing, and ice/snow climbing, which are regarded as high-risk activities, had low injury rates in this study, all less than that of backpacking. One major criticism of this study is that it addressed a predominately younger population. Of the 10,977 participants, 8094 were students and 86.9% of the students were under the age of 30 years. While boasting large numbers, diverse environments, and varying activities, this study likely does not represent the population participating in wilderness activities and in particular does not shine light on the true incidence and type of medical illnesses occurring in the wilderness. The general findings of this study were confirmed by Montalvo et al in a 1998 study examining injuries, illnesses, and mortality in national parks located in California [12]. These authors retrospectively examined fatal injuries in eight parks and nonfatal injuries in seven parks over a 3-year period. Of the 1708 injuries that occurred, musculoskeletal injury and soft tissue injury accounted for 70%. The lower extremities accounted for 38.5% of all injury locations followed by the upper extremities (27.1%), the head and neck (26.6%), and the torso (7.9%). In this study 25.6% of all incidents were caused by illnesses. Pain (1.9%), dizziness (1.8%), shortness of breath (1.8%), vomiting (1.6%), and dehydration/heat stroke (1.5%) accounted for the top five illnesses. The authors did not speculate on the high incidence of medically related events. Possible causes include an aging population in the United States and increased access to and interest in wilderness areas, especially in national parks. Of interest, cardiac death accounted for the most common cause of mortality, followed by drowning, falls (50–800 feet), motor vehicle accidents, and plane crashes. Another study published by Goodman et al in 2001 examined mortality in wilderness areas of Pima County, Arizona over the 13 years between 1980 and 1992 [13]. As with Montalvo’s study, falls were a causative factor in a large percentage of mortalities. Of the 100 deaths over the 13-year period, falls or falls with associated immersion/submersion/drowning accounted for 35% of all deaths. Technical rock climbing accounted for only one of these fatal falls. Alcohol might have played a role in the deaths associated with falls; 75% of this population was found to have positive alcohol levels on forensic examination. The most common injuries in this population were head and
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neck injuries. Suicides, drowning, and homicide rounded out the top four causes of death. Medical causes of mortality were not as prevalent in this study, accounting for 12% of deaths, with heat accounting for the majority followed by cardiac disease and diabetes. The authors of this study examined the causes of mortality and suggested that the majority of deaths occurred immediately after the accident or before the arrival of search and rescue teams. They therefore postulated that resources should be dedicated to prevention and public awareness rather than search and rescue in efforts to reduce mortality. In contrast to this belief, Schmidt et al published a study examining the Reach and Treat Team, a group of urban paramedics dual trained in wilderness medicine that responds to wilderness emergencies in the Portland, Oregon area [10]. In an innovative effort to reduce issues of skills depletion, the paramedics’ primary responsibility is to a larger urban area. The team responds from this area for the estimated 25 wilderness calls per year. The study retrospectively examined the experience of this team over a 5-year period. Confirming earlier studies, this study found that extremity injuries accounted for 50.9% of the 114 reported injuries with head injuries and hypothermia accounting for 15.8% and 13.2%, respectively. Ninety percent of patients received advanced level care, including 52 patients receiving intravenous lines, 40 receiving intravenous fluids, 24 receiving pain control (morphine), and 13 receiving antiemetics (droperidol). Eight patients were intubated, two patients received mannitol for closed head injuries, and two patients received CPR. While admitting that the clinical relevance of these advanced skills was difficult to determine, the authors found that times to intubation were reduced by 1.5 hours on average. While probability of survival data suggest that this patient population could have been expected to survive in normal prehospital conditions, it is uncertain if those same rules can be applied to wilderness settings. Even without mortality benefits, the Reach and Treat Team could affect morbidity by providing on-scene pain control and antiemetics during transport. Perhaps the major benefits of advanced medical care on scene for the majority of patients in wilderness settings is in the provision of care that reduces morbidity, not mortality. The aforementioned studies reflect the large advances made in the past decades to understand the unique and dynamic arena of wilderness medicine and the work necessary to further delineate this burgeoning field of medicine. For instance, major questions remain regarding the proper provisions of care to patients in the wilderness. Are Goodman et al correct to suggest that any excess resources delivered to search and rescue should be diverted to public education and prevention? Is Schmidt’s model of advanced medical skills the correct paradigm? What becomes clear from these studies is that the preponderance of emergencies occurring in the wilderness are not caused by exotic events (animal attacks, lightning, and so forth) but rather to more common events such as walking, hiking, skiing, and so forth. The most frequent injuries that befall this population of
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patients are caused by trauma, infections, and complications of underlying medical conditions, followed by the events that are typically thought of as ‘‘wilderness injuries.’’ The challenge for wilderness medicine and its practitioners is to model a system of care that allows for the treatment of these patients in a uniquely austere and dynamic environment. One overall correct model is difficult to speculate on, but it would likely involve a combination of the prototypes offered by Goodman and Schmidt and would involve public health measures such as prevention and education and a more robust emergent provision of care. This care must involve advanced medical protocols different from the standard urban or rural EMS setting. The challenges of wilderness medicine include addressing issues such as delayed time to definitive care with potential for complications or progression of the underlying injury or illness. Only through an assessment of local wilderness medical threats and local wilderness EMS needs can trained physicians, wilderness or Search and Rescue specialists, EMS providers, and appropriate public safety officials begin to address these issues.
Summary Wilderness medicine represents a unique field of medicine, combining elements from traditional medical specialties (especially emergency medicine and primary care medicine) with environmental injuries and illnesses and various rescue and EMS skills. Regardless of the arena in which they operate, the practitioners of wilderness medicine are exposed to various challenges including prolonged patient care, resource management, environmental stressors, evacuation difficulties, personnel management, and preparedness/prevention challenges. As the field of wilderness medicine has developed it has become clear that emergency incidents in the wilderness are in large part caused by trauma, infections, and complications of chronic disease followed by injuries or illnesses caused by environmental factors. One of the major challenges remaining for wilderness medicine in the United States is striving to determine the correct provision of care for patients in the wilderness.
Further readings Bowman WD. The development and current status of wilderness prehospital emergency care in the United States. J Wilderness Med 1990;1:93–102. Federiuk C. Clinical update on emergency medical care in the wilderness. Wilderness Environ Med 1999;10:20–4. Kaufman T, Knoop R, Webster T, et al. The Parkmedic Program: prehospital care in the national parks. Ann Emerg Med 1981;10(3):156–60. Paton BC. Health, safety and risk in outward bound. J Wilderness Med 1992;3:128–44. Peterson E, Snider W, Fahrenwald R. A model for wilderness medicine education in a family practice residency. Wilderness Environ Med 2002;13:266–8.
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Townes DA. Wilderness medicine. Primary Care: Clinics in Office Practice 2002;29(4):1027–48. Williamson J. Accidents in North American mountaineering—2002. American Alpine Club: Golden, CO; 2002.
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