Force of Nature Trauma in the Wilderness

LESSON 6

By Andrew Park, DO, MPH; and Thomas Seibert, MD, MS Dr. Park is a fellow of the Wilderness Medical Society and an assistant professor in the Department of Emergency Medicine at the University of Kansas Medical Center in Kansas City, Missouri. Dr. Seibert is a fellow of the Wilderness Medical Society and a wilderness medicine fellow at the University of Utah in Salt Lake City. Reviewed by Nathaniel Mann, MD OBJECTIVES On completion of this lesson, you should be able to: CRITICAL DECISIONS 1. Identify the most common traumatic injuries sustained n How should a patient be evaluated after a in wilderness settings. traumatic event in the wilderness? 2. Decide when to perform an emergent needle n When should needle decompression of the chest decompression of the chest in the field. be performed in the field? 3. Describe the factors to consider in evacuations. n When should a patient be treated in place versus 4. Determine the appropriate use of orthopedic being evacuated to definitive care? reductions. n When should an orthopedic fracture or dislocation 5. Determine the appropriate use of tourniquets. be reduced in the wilderness? n What factors should be considered before FROM THE EM MODEL applying a tourniquet? 18.0 Traumatic Disorders

A growing number of adventure-seekers are departing their urban confines to explore the great outdoors. As such, clinicians must be prepared to initiate life- and limb-saving treatments for wilderness-related injuries, even in the most austere environments and with limited resources and manpower.1,2 Proper planning and appropriate interventions can greatly affect outcomes, both in the field and in the emergency department. In light of the rising global interest in outdoor activities, it is increasingly important for clinicians to understand how to prevent, evaluate, and manage the traumatic injuries they are most likely to encounter as expedition medical officers, guides, trip leaders, or participants.

March 2019 n Volume 33 Number 3 19 CASE PRESENTATIONS ■ CASE ONE external rotation. Her left leg has a The bicyclist is able to speak in full visible deformity just above the knee. A 23-year-old musher and his sentences and remembers the accident. The patient’s pulse is 130, her dog team are making good time He denies shortness of breath, and on the Iditarod Trail in Alaska. respiration rate is 24, and she feels the physician notes an equal rise and As the trail turns away from the euthermic. An examination of her fall of the chest. The patient’s radial river and into a wooded area, the head, neck, arms, and torso are pulse bilaterally is 2+/4, and he is musher’s sled slides off the edge unremarkable, and her Glasgow Coma tachycardic. His GCS score is 15, and of a thin snow bridge, propelling Scale (GCS) score is 15. She is moving he is moving all extremities without him onto the end of a large branch. both arms and has 2+/4 bilateral radial difficulty. He was wearing a helmet An emergency physician and pulses. The physician removes the and has no deformities or signs of his friend discover the musher patient’s climbing shoes to measure her other injuries. while following the race on snow lower-extremity pulses, which are 2+/4 The physician cuts open the machines. The physician finds the in the right foot but weakly palpable in patient’s sleeve to reveal a deep man awake and alert but bent over the left foot. Additionally, the left foot puncture wound and laceration to with labored breathing. and calf feel cooler to the touch than the anterior aspect of the proximal On examination, the musher the right leg. Her sensation to light forearm. Brisk, bright red blood is touch is intact and symmetrical in all has a heart rate of 120 with good pulsating out. Re-examination distally bilateral lower dermatomes. distal perfusion, right chest wall reveals an intact radial pulse and The physician’s backpack contains tenderness, distended neck veins, sufficient capillary refill. As pressure a small first-aid kit with oral over-the- and a slight tracheal deviation to is applied to the wound, a medical counter medications, hiking poles, duct the left. His mental status is good, history is taken, which reveals no tape, a multi-tool, and an emergency but he is in pain. The nearest significant medical problems, no locator GPS system. The climbers have hospital is approximately 80 miles surgeries, and no allergies. away, and there is no road access. rope and small packs with snacks and Collectively, the cyclists are water. The group is 4 miles from the carrying a moderate amount of first- ■ CASE TWO trailhead, which is 2,200 feet lower aid supplies, oral pain control, bike A 50-year-old rock climber falls in altitude, and there is no cell phone repair kits, water, and cell phones. to the ground after her camming reception. device fails. Her frantic climbing The group is 2 miles from the parking partner summons help from a ■ CASE THREE lot, so one of the riders bikes out to group of hikers, which includes an A mountain biker loses control on the trailhead while another contacts emergency physician, who rushes to a tight turn and is thrown off the trail 911 and confirms that EMS is en the scene. The climber’s airway and into a pile of rocks. As others slow route. Despite the application of direct breathing are intact, but she is lying oncoming cyclists, one of the riders, pressure, the wound is still bleeding on the ground in obvious distress. an emergency physician, approaches around the bandage after 15 minutes. Her right leg appears shortened and sees blood dripping from the The patient thinks he can walk but is compared to the left and is held in patient’s sleeve at a concerning rate. feeling weak.

The distribution of death from reduced with proper assessment and CRITICAL DECISION trauma is trimodal in nature. The first treatment. In the wilderness setting, How should a patient be fatalities, which occur within the first however, it is unlikely that the victim evaluated after a traumatic few minutes of the event, usually arise will arrive at a trauma center within from catastrophic injuries (eg, aortic the “golden hour.”3 event in the wilderness? rupture, high spinal cord injuries). From 2007 to 2011, the US Researchers have described applying The second peak of fatalities occurs National Park System reported an the “golden principles” of prehospital in the first few hours and is usually average of 280 million annual visits. trauma care in the urban setting. associated with intracranial injuries, An estimated 32.5 out of every Although these guidelines were not pneumothoraces, and hemorrhagic anemia. The third peak is delayed 1 million visitors require a trauma or intended for use in wilderness medicine, 4 for days to weeks, likely secondary first-aid evaluation. Although this several key components are applicable to infection or other complications. frequency is low, it equates to 9,076 to outdoor settings. Rescuers should The term “golden hour” in trauma annual incidents.4 One study suggests continually evaluate the safety of both literature is used to describe the second that as many as 80% of these fatalities the patient and the provider; employ peak of fatalities, which can be greatly occur prior to evacuation.5 primary and secondary surveys; ensure

20 Critical Decisions in Emergency Medicine cervical spine immobilization (Figure 1); Next, a secondary survey should be complications should be considered address external hemorrhage; keep the performed to evaluate the patient first, including pneumothorax, patient warm; initiate early evacuation; from head to toe. When appropriate, tension pneumothorax, flail chest, and, above all, do no harm.3 it is important to completely undress and cardiac tamponade. A traumatic Once the patient is in the safest, the patient and examine all aspects of aortic dissection or rupture is likely most stable environment possible, the body for signs of injury. In some to be fatal before interventions can be the Advanced Trauma Life Support environments, however, full exposure employed. A patient with chest trauma (ATLS)–based steps of trauma can lead to hypothermia and further also must be evaluated for shortness of management should be implemented, as complications. In potentially dangerous breath, tachycardia, and altered mental adapted for the outdoors:6 locations, a full examination may be status, which can signal hypoxia. In 1. Primary survey impossible. In such cases, physicians these situations, a handheld pulse 2. Resuscitation should minimize exposure to the oximeter can be invaluable. 3. Secondary survey elements and use auscultation and The chest should then be examined 4. Definitive plan palpation to evaluate the patient. for major deformities, symmetry, 5. Packaging and transfer A thorough medical history should and other signs of trauma, including preparation also be taken, using the AMPLE tenderness with palpation and skin Even in the wilderness, the primary pneumonic (Allergies, Medications, damage or changes. An uneven survey should employ the ABCDEs of Past medical history, Last meal, Events chest wall rise, however subtle, is a any trauma evaluation:6 leading to injury) from the ATLS pathognomonic sign of flail chest • Airway maintenance and guidelines.6 The history and physical secondary to multiple rib fractures. A cervical spine stabilization examination can be used to generate deviated trachea away from the side • Breathing a list of injuries and discern which, if of injury, tachycardia, distended neck • Circulation and control of any, require immediate intervention or veins, and increased work of breathing significant external hemorrhage evacuation. In addition, factors such or hypoxia are all signs of a tension • Disability: neurological status as the severity of the trauma, possible pneumothorax. Altered mental status • Exposure/environmental control methods of evacuation, and potential may be present in cases of severe or Following the primary survey, the routes must be weighed. prolonged hypoxia or significant blood patient should be resuscitated with When managing chest trauma, loss from severe chest trauma, with or the available equipment and supplies. for example, the most serious without concomitant injuries. CRITICAL DECISION FIGURE 1. Wilderness Medical Society Focused Spine Assessment When should needle Blunt trauma decompression of the chest with a mechanism YES Awake, alert, and reliable? suspicious for be performed in the field? spine trauma YES NO Patients with severe symptoms following chest trauma must be • Severely injured patient? • Evidence of intoxication? evaluated for life-threatening injuries, • Neurological deficit? including a pneumothorax or tension • Thoracic or other pneumothorax. Patients with a significant distracting YES injury? suspected pneumothorax should be transported as quickly as possible NO to the nearest medical facility for Significant spine pain further evaluation and definitive YES Possible or tenderness (≥7/10)? Spine Injury treatment. Any patient without severe symptoms should be monitored for NO signs and symptoms of an expanding Isolated penetrating pneumothorax and a subsequent trauma? Patient voluntarily able NO tension pneumothorax. to flex, extend, and rotate spine in each plane The pathophysiology of a YES regardless of pain? tension pneumothorax includes the • 45° cervical spine development of a one-way valve No spine injury? • 30° thoracolumbar secondary to the injured lung tissue, YES which allows air to enter and expand the pleural space. Because the air No spine injury? is unable to escape and volume expansion is limited, the pressure in

March 2019 n Volume 33 Number 3 21 further evaluation and treatment but FIGURE 2. Pain Treatment Pyramid are at low risk of rapid decompensation or death. This determination should be made IV/IO with the help of everyone in the group, Meds including the patient, if possible. It is imperative for medical or rescue IM/IN leaders to: Transdermal • understand the capability of the group and the experience of its members; • know the capability of any local Oral Opioids rescue organizations and how to contact them; and • consider the geographical area Nonopioids and the timing necessary for an evacuation. Rescue leaders should also develop a coordinated plan that is communicated Comfort Care/PRICE Therapy to at least one person not involved in the trip. An awareness of these PRICE: Protection, Rest, Ice, Compression, Elevation limitations can help to more clearly

IM: Intramuscular IN: Intranasal IV: Intravenous IO: Intraosseous define when such decisions must be made. Adapted from the Wilderness Medical Society Practice Guidelines for the Treatment of Acute Pain in Remote Environments. After a trauma evaluation, the clinician must determine whether the patient s injury can be definitively the injured hemithorax increases. The When managing a patient in ’ treated in the field with the supplies lung on the affected side collapses, and the wilderness setting, it is always available or whether the injury, if the increased pressure displaces the important to minimize exposure and mediastinum contralaterally, resulting alleviate pain as much as possible not managed urgently, could worsen in compression of the superior and (Figure 2). As in the hospital setting, significantly. These decisions can be inferior venae cavae. These events once the needle decompression has much easier to make when assessing subsequently affect venous return been performed, the catheter should injuries at each end of the severity and reduce preload, prompting signs be secured in place. While preventing spectrum. For example, patients with and symptoms of shock. Indications entanglement, the patient should be minor wounds can often be treated in for immediate needle decompression reclothed to prevent further exposure. the field and released to continue their in a patient with chest trauma in the Frequent reassessments should journey. wilderness include: be performed to look for signs of Paul Auerbach’s authoritative • Significant shortness of breath decompensation and reaccumulation of Wilderness Medicine describes which 7 • Hypoxia or cyanosis the pneumothorax. patients require evacuation, including: • Distended neck veins 1. Those who do not improve or • Tracheal deviation CRITICAL DECISION deteriorate after treatment • Altered mental status When should a patient be 2. Those with debilitating pain 3. Those with an inability to Once a tension pneumothorax has treated in place versus being been identified, the severity of the injury sustain travel at a reasonable evacuated to definitive care? and the next steps should be discussed. pace due to a medical problem If help is available, someone else should Patients who become sick or injured 4. Those with persistent arrange for emergent evacuation while in the wilderness must be quickly abdominal pain the physician explains the importance evaluated, and a determination must 5. Those with signs and symptoms of needle decompression to the patient. be made as to whether they can be of serious high-altitude illness It is important to emphasize that the managed on-site or must be evacuated 6. Those with infections that do procedure is a potentially lifesaving for definitive treatment (Figure 3). not improve after 24 hours of therapy for a tension pneumothorax, Patients who are at risk of significant treatment a condition that can rapidly lead to complications or death require urgent 7. Those with chest pain cardiovascular collapse and death if left evacuation. Nonurgent evacuation not clearly from a minor untreated. can be considered for those who need musculoskeletal injury

22 Critical Decisions in Emergency Medicine 8. Those who develop a psychiatric hour, depending on the injury, terrain, whether a “pop” was heard. After issue that puts the patient or the and supplies. the primary survey and a focused group at risk Patients who are severely ill or have evaluation of the spine and pelvis, the 9. Those with large or serious sustained an injury with a high risk of clinician should concentrate on focal injuries or wounds with morbidity or mortality necessitate both extremity injuries.8 It is paramount complications (eg, an open on-site treatment and timely evacuation. to evaluate for deformities, fracture, fractures with Any urgent medical needs must be crepitus, swelling, skin changes, deformity, fractures with addressed on-site while evacuation is and neurovascular function. When impaired neurovascular status, simultaneously arranged. uncertain, the injured limb should be gunshot wounds, a suspected compared to the unaffected side. CRITICAL DECISION spinal cord injury, and certain Any dislocation that appears to burns) When should an orthopedic be an isolated injury can and should Travel toward definitive medical fracture or dislocation be be reduced on scene if the procedure care can continue in scenarios 3, reduced in the wilderness? can be accomplished safely. Early 4, and 8, or when descending in reductions are usually easier, when scenario 5. Evacuating a patient from Musculoskeletal trauma accounts swelling and muscle spasms are less a wilderness setting requires relaying for approximately 80% of wilderness- severe. In addition, early intervention important factors to EMS and search related accidents. Ankle fractures can significantly reduce pain and and rescue (SAR) personnel, including are the most commonly encountered mitigate the need for evacuation. a description of the patient’s injuries, injuries in the outdoor setting. Without If a fracture is associated with the the treatment given, the environmental immediate access to radiographs, a conditions, and the type of evacuation detailed history can help properly dislocation, a reduction is less likely required. Evacuation is a time- and diagnose orthopedic trauma. The to be successful and is therefore personnel-intensive task that often patient may be able to describe force discouraged. Techniques for reduction moves more slowly than 1 mile per vectors that led to the injury or state depend on the treating clinician, affected joint, and medicines available. Reductions of the fingers and patellae FIGURE 3. Evacuation Plan Flowchart can often be completed without any anesthesia. Ankles and shoulders Is the injury or illness severe can benefit from intra-articular, enough to require additional NO Is the person unable to intramuscular, or oral pain control medical treatment? Make continue with the trip? this assessment in a timely or anesthesia. A dislocated hip or manner. knee is a major injury that may not YES YES be reducible without sedation; in such cases, transport may be required.7 Can the patient walk NO As in the emergency department, out on their own Send without aggravating the appropriate patients who require an urgent condition? This person needs a litter members reduction in the wilderness include evacuation. Does the group NO of the those with decreased perfusion distally, YES have the skills, people, group out those with reduced neurological and equipment to safely to secure evacuate the person? professional function distally, and those at risk of Can the available evacuation NO help. developing compartment syndrome. routes be safely traveled by YES the patient? Traditionally, large deformities without these concerns were reduced Prepare for evacuation. YES and placed in external traction splints; however, this approach is no Will walking out and carrying Allow the patient to hike longer recommended. The Wilderness gear create additional NO out with appropriate group accident potential for the Medical Society practice guidelines support and with gear. patient or the group? discourage the routine use of traction splints on long-bone fractures YES (stereotypically femurs). Initially, Allow the person to hike in-line traction can provide relief; out with appropriate group however, prolonged external traction support, but do not let them devices or improvisations can lead to carry gear. skin necrosis and reduced circulation, and have no proven benefit.8

March 2019 n Volume 33 Number 3 23 Summary It is imperative for emergency physicians to recognize how proper planning, evaluation, and treatment can greatly affect the outcomes of patients who have been injured in wilderness n Patients with chest wounds, extreme dyspnea, loss of unilateral breath sounds, or signs of a tension pneumothorax require an immediate needle decompression settings. A timely trauma survey can of the chest. help differentiate between minor injuries n Patients who have signs of acute blood loss, altered mental status, a life- and those that require immediate life- threatening condition, or progressively worsening symptoms should be evacuated or limb-saving treatment. as quickly as possible. The timely identification of a n Patients with a loss of pulses or feeling in a fractured or dislocated extremity tension pneumothorax is critical when should undergo emergent reduction of the affected limb. managing patients with chest trauma. n A tourniquet should be applied to stop bleeding that fails to respond to the Such cases mandate immediate needle application of direct pressure. decompression of the chest followed by emergent evacuation to the nearest medical facility. Patients with fractures study were removed prior to the 2-hour CRITICAL DECISION or dislocations that compromise the mark.10 What factors should be distal tissues, or those with other One of the biggest mistakes a complicating factors such as evacuation considered before applying clinician can make when applying a a tourniquet? times, require emergent reduction of tourniquet in the prehospital setting the affected limb to prevent further Hemorrhagic shock is the leading is failing to tighten it enough. An morbidity. cause of death on the military battlefield estimated 83% of extremities have Penetrating trauma to the and is the second leading cause of palpable distal pulses upon hospital extremities with uncontrolled blood traumatic deaths in the civilian sector. arrival, which can lead to a “venous loss puts patients at grave risk for Because of this risk — which is inherent tourniquet” that increases the risk of hypovolemic shock and death; in these in any low-resource environment, compartment syndrome or increased situations, tourniquets must be applied including the wilderness — the United blood loss by allowing inflow while promptly and properly. Clinicians States Armed Forces developed the precluding a return to systemic must also be prepared to weigh a 11,12 MARCH mnemonic to direct the initial circulation from the injured limb. variety of environment-specific factors assessment of soldiers injured during Tourniquets are a safe and when devising a treatment plan and combat operations: effective way to treat wounds with determining the need for evacuation. • Massive hemorrhage significant bleeding. If direct pressure is • Airway ineffective, the next step should be the REFERENCES • Respirations application of a tourniquet proximal to 1. National Center for Injury Prevention and Control. Ten leading causes of death and injury. Centers for • Circulation the wound, which should be tightened Disease Control and Prevention website. http://www. cdc.gov/injury/wisqars/leadingcauses.html. Published • Head injuries/hypothermia until the distal pulses are occluded. February 25, 2016. Accessed November 20, 2016. This battlefield protocol has been successfully employed in wilderness sectors. Applying a tourniquet before a victim goes into shock appears to provide a profound survival benefit (96% vs 4%). Prehospital application vs hospital application also appears to n Failing to prepare for the most common injuries encountered in the wilderness improve the likelihood of survival or for specific types of travel, an oversight that can adversely impact a 9 (89% vs 78%, p <0.05). physician’s ability to effectively respond to emergencies in the field. There appears to be no correlation n Waiting too long to reduce a fracture or dislocation. Delays can make the between morbidity and the time a reduction of the affected limb more difficult due to increased muscle spasms tourniquet stays in place, and no increase and swelling around the wound. Delaying reduction can also adversely affect the in thromboembolic events, necrosis, tissue distally. amputation, or renal failure. Research n Using improper techniques or equipment, including external traction splints, also shows a slight, but statistically which are no longer recommended. significant, increase in the need for a n Failing to adapt emergency procedures to the outdoor setting, which can lead fasciotomy if the tourniquet remains in to complications and death. place for more than 2 hours; however, n Neglecting to recognize when an emergent evacuation is warranted, a mistake 91% of tourniquets in the referenced that can increase morbidity and mortality.

24 Critical Decisions in Emergency Medicine CASE RESOLUTIONS ■ CASE ONE secondary to decreased barometric The physician indicated an Within minutes, the musher pressure at higher altitude. On arrival emergency on the GPS locator, and became tachycardic and dyspneic. at the medical center, a chest tube was the group waited nearly 4 hours The initial trauma survey revealed placed, and the patient was admitted for the SAR team to appear. A a chest wound accompanied by for further observation. paramedic administered fentanyl shortness of breath and absent breath intramuscularly (100 mcg). The sounds on the right side. Because ■ CASE TWO patient was then placed in a vacuum the musher also had distended neck The physician suspected that the litter, fitted with a cervical collar, veins and a tracheal deviation to the fallen rock climber had sustained a and packaged into a one-wheeled left, the physician suspected a tension right hip fracture and/or dislocation litter. It took 8 hours to reach pneumothorax, a life-threatening and a left distal femur fracture with the ambulance at the trailhead. injury that requires immediate needle significant displacement, which was At the local hospital, the patient decompression to prevent further contributing to vascular compromise was diagnosed with a right hip cardiovascular decompensation and distally. No additional injuries were dislocation and a left distal femur death. As the patient’s symptoms found. The skin was intact, and no fracture. With procedural sedation, worsened, treating the tension signs of external hemorrhage existed. the hip was reduced, and she was pneumothorax became paramount. Because of decreased perfusion, the admitted for surgical repair of the While the physician discussed physician focused on the left leg first. left femur. the urgency of the injuries with He administered ibuprofen (800 mg) the patient, the friend called for and acetaminophen (1 g) orally and ■ CASE THREE immediate evacuation to the nearest applied gentle in-line traction, which The physician fashioned a wide medical facility and provided their initially caused significant pain but led tourniquet from a spare bike tube coordinates. The physician performed to improved comfort. Reassessment and a sturdy branch, which was a needle decompression of the chest of the leg revealed improvement in the placed 4 inches proximal to the and heard a rush of air from the visible deformity and a 2+/4 dorsalis cyclist’s wound. Twisting the branch musher’s chest. Pain medicine was pedis pulse. The warmth and color of increased the tension and eventually administered (800 mg of ibuprofen the leg improved. occluded the radial pulse. When and 1 g of acetaminophen by mouth), The physician was unsure if the the bleeding abated, the physician and the patient was re-evaluated woman’s right leg was fractured or changed the dressing and applied frequently to assess for pain, clinical a pressure dressing directly to the stability, and comfort. The physician dislocated but did not believe she instructed the musher to slide into his had an open-book pelvic fracture. wound. sled to stay out of the wind, as the Concerned about how painful a Pain medication and oral fluids group sheltered in the wooded area. reduction attempt would be given the were given. With assistance, the Approximately 45 minutes later, a lack of pharmacological supplies and patient ambulated slowly toward rescue helicopter landed on the frozen the inability to determine concomitant the trailhead. The group was met river, and the flight medic signaled pelvic or femur fractures, he deferred by EMS, who established an IV and that he was ready for the patient. The intervention; splinted the legs together transferred the patient to the local physician relayed to the flight crew with the knees in slight flexion, hospital. CT angiography showed that the catheter used to decompress with padding between the thighs a laceration to the proximal ulnar the patient’s chest was still in place. and in the popliteal fossae; and then artery. The patient underwent urgent The pilot stated he would fly low to confirmed that the patient was still vascular repair and was discharged reduce the chance of re-expansion neurovascularly intact. in stable condition a few days later.

2. Hubbell FR. Wilderness emergency medical 6. American College of Surgeons Committee on 10. Kragh JF Jr, Walters TJ, Baer DG, et al. Practical services and response systems. In: Auerbach PS, Trauma. ATLS: Advanced Trauma Life Support for use of emergency tourniquets to stop bleeding ed. Wilderness Medicine. 5th ed. Philadelphia, PA: Doctors. 8th ed. Chicago, IL: American College of in major limb trauma. J Trauma. 2008 Feb;64 Mosby Elsevier; 2007:694-707. Surgeons; 2008:2-11. (2 Suppl):S38-S50. 3. Collier BR, Riordan PR Jr, Nagy JR, Morris JA 7. Switzer JA, Ellis TJ, Swiontkowski MF. Wilderness 11. King DR, van der Wilden G, Kragh JF Jr, Jr. Wilderness trauma, surgical emergencies, orthopedics. In: Auerbach PS, ed. Wilderness Blackbourne LH. Forward assessment of 79 and wound management. In: Auerbach PS, ed. Medicine. 5th ed. Philadelphia, PA: Mosby Elsevier; prehospital battlefield tourniquets used Wilderness Medicine. 5th ed. Philadelphia, PA: 2007:573-603. in the current war. J Spec Oper Med. 2012 Mosby Elsevier; 2007:475-504. 8. Forgey WW; Wilderness Medical Society. Winter;12(4):33-38. 4. Declerck MP, Atterton LM, Seibert T, Cushing TA. A Wilderness Medical Society: Practice Guidelines for 12. Drew B, Bennett BL, Littlejohn L. Application review of emergency medical services events in US Wilderness Emergency Care. 5th ed. Guilford, CT: of current hemorrhage control techniques for national parks from 2007 to 2011. Wilderness Environ Morris Book Publishing; 2006. backcountry care: part one, tourniquets and Med. 2013 Sep;24(3):195-202. 9. Kragh JF Jr, Littrel ML, Jones JA, et al. Battle hemorrhage control adjuncts. Wilderness Environ 5. Goodman T, Iserson KV, Strich H. Wilderness casualty survival with emergency tourniquet Med. 2015 Jun;26(2):236-245. mortalities: a 13-year experience. Ann Emerg Med. use to stop limb bleeding. J Emerg Med. 2011 2001 Mar;37(3):279-283. Dec;41(6):590-597.

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