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Managing Traumatic Brain Injury: Translating Military Guidelines to the Wilderness

      Traumatic brain injury (TBI) is a common injury on the battlefield. Much of what medics do to manage these injuries on the battlefield can be translated to other austere environments, such as wilderness or disaster settings. The recognition and diagnosis of TBI can be difficult even in the hospital, but basic understanding of how to define a TBI and prevent secondary injuries can be accomplished with relatively few resources and little training. This article outlines what a TBI is and how to manage it in the field.

      Keywords

      Introduction

      Traumatic brain injury (TBI) is the signature injury identified from the most recent conflicts in Iraq and Afghanistan.
      • Warden D.
      Military TBI during the Iraq and Afghanistan wars.
      While most brain injuries on the battlefield are due to blast and fragments from explosive devices, wilderness TBIs are primarily due to falls during mountaineering activities, but can also occur during cycling, snowboarding, skiing, diving, and hunting and via any other mechanisms that transmit enough force to the victim’s head to cause an injury to the brain.
      • Gentile D.A.
      • Morris J.A.
      • Schimelpfenig T.
      • Bass S.M.
      • Auerbach P.S.
      Wilderness injuries and illnesses.
      • Stephens B.D.
      • Diekema D.S.
      • Klein E.J.
      Recreational injuries in Washington state national parks.
      • Haider A.H.
      • Saleem T.
      • Bilaniuk J.W.
      • Barraco R.
      On behalf of the Eastern Association for the Surgery of Trauma Injury Control/Violence Prevention Committee
      An evidence-based review: efficacy of safety helmets in reduction of head injuries in recreational skiers and snowboarders.
      • Bauer D.
      • Tung M.L.
      • Tsao J.W.
      Mechanisms of traumatic brain injury.
      Five to 50 percent of traumatic events in the wilderness result in some form of TBI.
      • Gentile D.A.
      • Morris J.A.
      • Schimelpfenig T.
      • Bass S.M.
      • Auerbach P.S.
      Wilderness injuries and illnesses.
      • Stephens B.D.
      • Diekema D.S.
      • Klein E.J.
      Recreational injuries in Washington state national parks.
      • Haider A.H.
      • Saleem T.
      • Bilaniuk J.W.
      • Barraco R.
      On behalf of the Eastern Association for the Surgery of Trauma Injury Control/Violence Prevention Committee
      An evidence-based review: efficacy of safety helmets in reduction of head injuries in recreational skiers and snowboarders.
      • Bauer D.
      • Tung M.L.
      • Tsao J.W.
      Mechanisms of traumatic brain injury.
      • Montalvo R.
      • Wingard D.L.
      • Bracker M.
      • Davidson T.M.
      Morbidity and mortality in the wilderness.
      • Kronisch R.L.
      • Pfeiffer R.P.
      Mountain biking injuries: an update.
      • Federiuk C.S.
      • Schlueter J.L.
      • Adams A.L.
      Skiing, snowboarding, and sledding injuries in a northwestern state.
      The incidence in avalanche victims has been reported to be as high as 25%.
      • Christensen M.L.
      • Jackson C.
      Skiing and snowboarding–related head injuries in the United States: a retrospective analysis from 2004–2010.
      • Boyd J.
      • Haeglei P.
      • Abu-Laban R.B.
      • Shuster M.
      • Butt J.C.
      Patterns of death among avalanche fatalities: a 21-year review.
      • McIntosh S.E.
      • Grissom C.K.
      • Olivares C.R.
      • Kim H.S.
      • Tremper B.
      Cause of death in avalanche fatalities.
      • Johnson S.M.
      • Johnson A.C.
      • Barton R.G.
      Avalanche trauma and closed head injury: adding insult to injury.
      • Vargyas G.
      Backcountry skiers, avalanche trauma mortality, and helmet use.
      The US Centers for Disease Control and Prevention estimated that the combined rates of TBI injuries and deaths increased from 521 per 100,000 in 2001 to 824 per 100,000 in 2010.

      Centers for Disease Control and Prevention. Rates of TBI-related emergency department visits, hospitalizations, and deaths — United States, 2001–2010. Available at: http://www.cdc.gov/traumaticbraininjury/data/rates.html. Accessed April 17, 2017.

      This increased incidence may represent an increase in detection with the widespread use of computed tomography (CT) scan imaging and increased recognition as an entity by medical providers. The rate of US TBI deaths during this period has remained stable at 17 to 18 per 100,000.

      Centers for Disease Control and Prevention. Rates of TBI-related emergency department visits, hospitalizations, and deaths — United States, 2001–2010. Available at: http://www.cdc.gov/traumaticbraininjury/data/rates.html. Accessed April 17, 2017.

      • Stein S.C.
      • Georgoff P.
      • Meghan S.
      • Mizra K.
      • Sonnad S.S.
      150 years of treating severe traumatic brain injury: a systematic review of progress in mortality.
      While rapid evacuation has been aggressively used by the military, especially in a mature combat theater, many wilderness injuries must be treated for hours to days before transport to a medical facility can be accomplished. Diagnostic modalities in both scenarios are similar, however, because both the battlefield and the wilderness medic must rely on a basic clinical examination and history (this examination and history, rather than CT imaging, is used to determine the mode and urgency of evacuation). In addition, many of the therapies available are the same. Prevention of secondary injury and rapid evacuation are the keystones of prehospital TBI treatment.
      • Boer C.
      • Franschmann G.
      • Loer S.A.
      Prehospital management of severe traumatic brain injury: concepts and ongoing controversies.
      • Badjatia N.
      • Carney N.
      • Crocco T.J.
      • et al.
      Guidelines for prehospital management of traumatic brain injury 2nd edition.
      • Carney N.
      • Totten A.M.
      • O’Reilly C.
      • Ullman J.S.
      • et al.
      Guidelines for the management of severe traumatic brain injury.
      • Huang S.J.
      • Hong W.C.
      • Han Y.Y.
      • et al.
      Clinical outcome of severe head injury using three different ICP and CPP protocol-driven therapies.
      • Harmon K.G.
      • Drezner J.A.
      • Gammons M.
      • et al.
      American Medical Society for Sports Medicine position statement: concussion in sport.
      • Meyer M.
      • Megyesi J.
      • Meythaler J.
      • et al.
      Acute management of acquired head injury part 1: an evidence-based review of non-pharmacological interventions.
      • Minardi J.
      • Crocco T.
      Management of traumatic brain injury: first link in chain of survival.
      While prehospital TBI management is really no different in the military and civilian arenas, other than medication use (ketamine and hypertonic saline) perhaps, the military’s emphasis on immediate evacuation, early and aggressive decompression, and invasive monitoring during early postoperative care has been demonstrated to lead to improved outcomes in penetrating brain injuries.
      • Wijayatilake D.S.
      • Jigajinni S.V.
      • Sherren P.B.
      Traumatic brain injury: physiological targets for clinical practice in the prehospital setting and on the Neuro-ICU.
      • DuBose J.J.
      • Barmparas G.
      • Inaba K.
      • et al.
      Isolated severe traumatic brain injuries sustained during combat operations: demographics, mortality outcomes, and lessons to be learned from contrasts to civilian counterparts.

      Definition

      TBI has been broadly classified as either mild, moderate, or severe. Part of this definition is based on the 15-point, modified Glasgow Coma Score (GCS), which has been used to assess neurologic condition after a head injury (Table). A pathoanatomic classification also helps define the underlying injury and includes subdural hematoma, epidural hematoma, subarachnoid hemorrhage, cerebral contusion, and diffuse axonal injury. Often, the more severe the anatomic injury, as documented by CT scan, the more severe the TBI.
      • Weisbrod A.B.
      • Rodriguez C.
      • Bell R.
      • et al.
      Long-term outcomes of combat casualties sustaining penetrating traumatic brain injury.

      Gerberding JL, Binder S. Report to Congress on mild traumatic brain injury in the United States: steps to prevent a serious public health problem. Available at: https://www.cdc.gov/traumaticbraininjury/pdf/mtbireport-a.pdf. Accessed April 17, 2003.

      TableGlasgow Coma Score
      Clinicians use this scale to rate the best eye opening response, the best verbal response, and the best motor response an individual makes. The final GCS score is the sum of these numbers.
      123456
      ENo eye openingOpens eyes to painful stimuliOpens eyes to verbal stimuliOpens eyes spontaneouslyN/AN/A
      VMakes no soundsIncomprehensible soundsIncoherent wordsConfused, disorientedOriented, converses normallyN/A
      MMakes no movementsExtension to painful stimuli (decerebrate)Flexion to painful stimuli (decorticate)Withdrawal to painful stimuliLocalizes to painful stimuliObeys commands
      E, eye; V, verbal; M, motor.
      a Clinicians use this scale to rate the best eye opening response, the best verbal response, and the best motor response an individual makes. The final GCS score is the sum of these numbers.
      Mild TBI, which accounts for over 80 to 90% of all TBIs, has been defined by the American Congress of Rehabilitation Medicine criteria as an acute condition in which the patient has sustained a trauma-induced (which includes the head being struck, the head striking an object, or the brain undergoing an acceleration/deceleration movement without direct external trauma to the head
      • Papa L.
      • Brophy G.M.
      • Welch R.D.
      • et al.
      Time course and diagnostic accuracy of glial and neuronal blood markers GFAP and UCH-L1 in a large cohort of trauma patients with and without mild traumatic brain injury.
      ) physiologic disruption of brain function, as manifested by one of the following: 1) any period of loss of consciousness (LOC); 2) any loss of memory of events immediately before or after the accident; 3) any alteration of mental state at the time of the accident (feeling dazed, disoriented, and/or confused); and 4) focal neurologic deficits that may or may not be permanent. To meet criteria for a mild TBI (mTBI) LOC must be less than 30 minutes in duration, the initial GCS (post LOC) should be 13–15, and posttraumatic amnesia should be less than 24 hours.
      Most TBIs will be mild (a concussion). The military has developed diagnostic tools for evaluating mTBI on the battlefield using the Military Acute Concussion Evaluation (MACE) and the Standardized Assessment of Concussion (SAC).
      • Knuth T.
      • Letarte P.B.
      • Ling B.
      • et al.
      Guidelines for the Field Management of Combat Related Head Trauma..
      • Jaffee M.S.
      • Helmick K.M.
      • Girard P.D.
      • Meyer K.S.
      • Dinegar K.
      • George K.
      Acute clinical care and care coordination for traumatic brain injury within Department of Defense.
      Concussions have 3 grades of severity based on LOC and duration of altered mental status (AMS).
      • Ropper A.H.
      • Gorson K.C.
      Clinical practice. Concussion.
      • Ruff R.M.
      • Iverson G.L.
      • Barth J.T.
      • et al.
      Recommendations for diagnosing mild traumatic brain injury: a National Academy of Neuropsychology education paper.
      Grade 1 is no LOC and less than 15 minutes of AMS; grade 2, no LOC and greater than 15 minutes of AMS; grade 3 is any LOC. The GCS ranges from 13 to 15.
      Moderate TBI is prolonged LOC greater than 30 minutes (but less than 24 hours) and a neurologic deficit with a GCS of 9 to 12.
      Mild Traumatic Brain Injury Committee of the Head Injury Interdisciplinary Special Interest Group of the American Congress of Rehabilitation Medicine
      Definition of mild traumatic brain injury.
      Severe TBI is LOC greater than 24 hours with a GCS less than 9. Moderate and severe TBI patients usually have an intracranial abnormality and significant neurologic deficits; in addition, they may be comatose, have a seizure, or have unstable vital signs.
      • Boer C.
      • Franschmann G.
      • Loer S.A.
      Prehospital management of severe traumatic brain injury: concepts and ongoing controversies.
      • Badjatia N.
      • Carney N.
      • Crocco T.J.
      • et al.
      Guidelines for prehospital management of traumatic brain injury 2nd edition.
      • Harmon K.G.
      • Drezner J.A.
      • Gammons M.
      • et al.
      American Medical Society for Sports Medicine position statement: concussion in sport.
      While the GCS was originally devised to predict outcome in head injury cases, it is more complex to use than other scores, and conditions other than TBI (ie, drugs, high altitude cerebral edema, or shock) may lower the score even in the absence of brain injury. Other methods of evaluation in the acute phase may be more expedient in the field, such as the best GCS-motor score (GCS-M) or the AVPU scale, which uses 4 simple categories (Alert; Verbal response; response to Pain; Unresponsive). While not used to define the severity of TBI, the AVPU scale is simple and a practical assessment of level of consciousness for first-providers.
      • Badjatia N.
      • Carney N.
      • Crocco T.J.
      • et al.
      Guidelines for prehospital management of traumatic brain injury 2nd edition.
      Mild Traumatic Brain Injury Committee of the Head Injury Interdisciplinary Special Interest Group of the American Congress of Rehabilitation Medicine
      Definition of mild traumatic brain injury.
      • Eastridge B.J.
      • Butler F.
      • Wade C.D.
      • et al.
      Field triage score (FTS) in battlefield casualties: validation of a novel triage technique in a combat environment.
      The “best” motor score is another less cumbersome assessment; when combined with pupillary reaction, it has been shown to be highly predictive of underlying injury and 6-month mortality.
      • Mena J.H.
      • Sanchez A.I.
      • Rubiano A.M.
      • et al.
      Effect of the modified Glascow Coma Scale score criteria for mild traumatic brain injury on mortality prediction: comparing classic and modified Glascow Coma Scale model scores of 13.
      • Majdan M.
      • Steyerberg E.W.
      • Nieboer D.
      • Mauritz W.
      • Rusnak M.
      • Lingsma H.F.
      Glasgow coma scale motor score and pupillary reaction to predict six-month mortality in patients with traumatic brain injury: comparison of field and admission assessment.
      While a primary injury is often caused by a mechanical insult to the brain, secondary injuries are nonmechanical damage that occur after the primary injury. Secondary injuries may be caused by hypotension, hypoxia, inadvertent hypo- or hyperventilation, and hyperthermia and can dramatically worsen the casualty’s outcome. Prehospital hypotension or hypoxia have been reported to nearly double the mortality rate.
      • Chesnut R.M.
      • Marshall S.B.
      • Piek J.
      • Blunt B.A.
      • Klauber M.R.
      • Marshall L.F.
      Early and late systemic hypotension as a frequent and fundamental source of cerebral ischemia following severe brain injury in the Traumatic Coma Data Bank.
      • Chi J.H.
      • Knudson M.M.
      • Vassar M.J.
      • et al.
      Prehospital hypoxia affects outcome in patients with traumatic brain injury: a prospective multicenter study.
      Patients who are intubated and undergoing bag-valve-mask ventilation are especially at risk for inadvertent hyperventilation, which leads to vasoconstriction and ultimately brain ischemia if prolonged and worse outcomes.
      • Warner K.J.
      • Cuschieri J.
      • Copass M.K.
      • Jurkovich G.J.
      • Bulger E.M.
      The impact of prehospital ventilation on outcome after severe traumatic brain injury.
      While therapeutic hypothermia in severe TBI has not been shown to be efficacious as a treatment,
      • Andrews P.J.D.
      • Sinclair H.L.
      • Rodriguez A.
      • et al.
      Hypothermia for intracranial hypertension after traumatic brain injury.
      hyperthermia has been demonstrated to be harmful.
      • Thompson H.J.
      • Tkacs N.C.
      • Saatman K.E.
      • Raghupathi R.
      • McIntosh T.K.
      Hyperthermia following traumatic brain injury: a critical evaluation.
      In addition, secondary injury may be exacerbated when the cerebral perfusion pressure (CPP) is less than 60 mm Hg. The CPP is determined by subtracting the intracranial pressure (ICP) from the mean arterial pressure (MAP), (CPP = MAP – ICP). When the MAP falls below 60 mm Hg and/or the ICP increases above 20 mm Hg, then the CPP decreases, likely worsening outcome. Increased ICP can be caused by bleeding in or around the brain or edema from hypoxia, ischemia, or injury. While CPP cannot be measured in the field, signs of increased ICP may be detected by a decrease in the level of consciousness or motor posturing; suspected herniation may be detected by development of asymmetric pupils or hemiparesis (a lateralizing sign). Maintaining a normal ICP, a normal MAP, and a CPP >60 mm Hg
      • Carney N.
      • Totten A.M.
      • O’Reilly C.
      • Ullman J.S.
      • et al.
      Guidelines for the management of severe traumatic brain injury.
      • Huang S.J.
      • Hong W.C.
      • Han Y.Y.
      • et al.
      Clinical outcome of severe head injury using three different ICP and CPP protocol-driven therapies.
      is associated with improved outcomes.
      • Carney N.
      • Totten A.M.
      • O’Reilly C.
      • Ullman J.S.
      • et al.
      Guidelines for the management of severe traumatic brain injury.
      • Meyer M.
      • Megyesi J.
      • Meythaler J.
      • et al.
      Acute management of acquired head injury part 1: an evidence-based review of non-pharmacological interventions.
      • Wijayatilake D.S.
      • Jigajinni S.V.
      • Sherren P.B.
      Traumatic brain injury: physiological targets for clinical practice in the prehospital setting and on the Neuro-ICU.
      • Kupersmith J.
      • Lew H.L.
      • Ommaya A.K.
      • Jaffee M.
      • Koroshetz W.J.
      Traumatic brain injury research opportunities: results of Department of Veterans Affairs Consensus Conference.

      Management

      The initial evaluation of a patient with suspected TBI should be done as soon as possible after the acute injury, when it is safe to do so. For example, a climber who falls or is struck by an object and has sustained a head injury should be safely brought to the ground as soon as possible for further examination. A rescuer who puts himself or herself in danger may become a second victim and thus unable to care for the first. Many head injuries in the wilderness are associated with spine injuries, and caution should be taken to immobilize the spine, if possible, when moving a patient to a safe area. Airway, breathing, and circulation should be assessed as soon as possible, and bleeding should be controlled. Scalp bleeding may be controlled by direct pressure but may also require a suture. The patient’s level of consciousness should be assessed (using GCS, AVPU, or the “best” motor score), and a primary survey of injuries should be completed. In addition, a quick assessment for localizing signs (hemiparesis) and pupil size and reactivity is necessary to complete the primary survey. All lifesaving interventions that are necessary and possible should be implemented at this time. Positioning is the most critical factor in airway management, and airway adjuncts such as jaw thrust, nasal pharyngeal airways, supraglottic airway, endotracheal intubation, or cricothyroidotomy should be performed as indicated. Tension pneumothorax, flail chest, or open pneumothorax should be treated if present, and the patient should be positioned so that normal temperature can be maintained. Hypothermia is a far greater risk than hyperthermia in the acute phase. For example, a snowboarder with a head injury should not be placed directly on the snow while examination and treatment is carried out. If monitoring equipment is available, blood pressure, oxygen saturation, capnography, and glucose should be measured. If monitoring is unavailable, the patient’s level of consciousness, mental status, pupil size, motor response, pulse, and respiration should be the minimum observed and recorded to assess for changes in the patient’s status.
      • Meyer M.
      • Megyesi J.
      • Meythaler J.
      • et al.
      Acute management of acquired head injury part 1: an evidence-based review of non-pharmacological interventions.
      • Minardi J.
      • Crocco T.
      Management of traumatic brain injury: first link in chain of survival.
      • Wijayatilake D.S.
      • Jigajinni S.V.
      • Sherren P.B.
      Traumatic brain injury: physiological targets for clinical practice in the prehospital setting and on the Neuro-ICU.
      • Knuth T.
      • Letarte P.B.
      • Ling B.
      • et al.
      Guidelines for the Field Management of Combat Related Head Trauma..
      • Risdall J.E.
      • Menon D.K.
      Traumatic brain injury.
      • Stiver S.I.
      • Manley G.T.
      Prehospital management of traumatic brain injury.
      Although it is impossible to predict which mild TBIs will progress and thus which patients will need to be evacuated, all patients with moderate or severe TBI should be evacuated as soon as possible. Maintaining vital signs and normal temperature and minimizing additional trauma is crucial.
      • Knuth T.
      • Letarte P.B.
      • Ling B.
      • et al.
      Guidelines for the Field Management of Combat Related Head Trauma..
      In general, hypo- and hyperventilation should be avoided. Mild hyperventilation can be used for brief periods if the patient shows signs of impending herniation
      • Blackbourne L.H.
      • Cole J.
      • Mabry R.
      • et al.
      The “silent killer”: hyperventilation in the brain injured.
      ; these include asymmetric or nonreactive pupils (in patients without eye injuries), extensor posturing, and/or no motor response (not from spinal cord injury). Patients with signs of herniation should be given a bolus of hypertonic saline if available, temporarily hyperventilated to a PaCO2 of 30 to 35 mm Hg, and have their head elevated greater than 30 degrees if possible.
      • Rockswold G.L.
      • Solid C.A.
      • Paredes-Andrade E.
      • Rockswold S.B.
      • Jancik J.T.
      • Quickel R.R.
      Hypertonic saline and its effect on intracranial pressure, cerebral perfusion pressure and brain tissue oxygen.
      • Ropper A.H.
      Hyperosmolar therapy for raised intracranial pressure.
      A bag-valve-mask can be used to support ventilation. If capnography is not available, then a respiratory rate of 12 breaths per minute for normal ventilation, or a rate of 16 breaths per minute for hyperventilation, may be used. Blood pressure of either MAP >60 mm Hg or systolic blood pressure >100 mm Hg should be maintained.
      • Carney N.
      • Totten A.M.
      • O’Reilly C.
      • Ullman J.S.
      • et al.
      Guidelines for the management of severe traumatic brain injury.
      • Huang S.J.
      • Hong W.C.
      • Han Y.Y.
      • et al.
      Clinical outcome of severe head injury using three different ICP and CPP protocol-driven therapies.
      A weak or absent radial pulse may indicate a systolic blood pressure <90 mm Hg. Raising the victim’s legs may increase the venous return and blood pressure if fluids are not available. If oxygen is available, O2 saturation should be kept at 90 to 96%, with hyperoxia avoided. The field methods for treating increased intracranial pressure and herniation are temporary measures, and rapid evacuation to a medical facility with neurosurgical capability is critical (algorithm summarized in Figure 1).
      • Boer C.
      • Franschmann G.
      • Loer S.A.
      Prehospital management of severe traumatic brain injury: concepts and ongoing controversies.
      • Meyer M.
      • Megyesi J.
      • Meythaler J.
      • et al.
      Acute management of acquired head injury part 1: an evidence-based review of non-pharmacological interventions.
      • Minardi J.
      • Crocco T.
      Management of traumatic brain injury: first link in chain of survival.
      • Wijayatilake D.S.
      • Jigajinni S.V.
      • Sherren P.B.
      Traumatic brain injury: physiological targets for clinical practice in the prehospital setting and on the Neuro-ICU.
      • Stiver S.I.
      • Manley G.T.
      Prehospital management of traumatic brain injury.
      • Reid M.W.
      • Velez C.S.
      Discriminating military and civilian traumatic brain injuries.
      Figure 1
      Figure 1Algorithm for treating increased intracranial pressure and herniation in the field. (Algorithm designed by the authors.)
      The prehospital care guidelines of the military are outlined by the Committee on Tactical Combat Casualty Care (CoTCCC).
      National Assoication of Emergency Medical Technicians (NAEMT)
      In making recommendations for prehospital care, this committee takes into consideration austere environments, tactical, and logistical factors. The guidelines are evidence-based, but given the environment in which they are practiced other factors may be more compelling for their adoption than the literature foundation. As an example, mannitol had been recommended for the treatment of severe TBI in the now-outdated third edition of the Brain Foundation’s Guidelines for the Management of Severe Traumatic Brain Injury.
      Brain Trauma FoundationAmerican Association of Neurological SurgeonsCongress of Neurological Surgeons.
      Guidelines for the management of severe traumatic brain injury.
      However, due to mannitol’s tendency to precipitate or freeze, its fragile glass bottle storage, and the difficulty of reconstituting the medication, it was never adopted as a viable alternative for the treatment of intracranial hypertension in the forward setting by the CoTCCC. The CoTCCC’s recommended management of TBI in the field is summarized in Figure 2.
      Figure 2
      Figure 2The CoTCCC–recommended management of traumatic brain injury in the field.
      National Assoication of Emergency Medical Technicians (NAEMT)
      Patients with mTBI should be re-evaluated in the field, but their immediate evacuation is less critical. However, depending on the underlying pathology, they may deteriorate as any TBI case may, and all patients need ongoing monitoring and follow-up evaluation. Patients with painful injuries may be given analgesics to control pain with the understanding that it may change their examination. Ketamine (as suggested in Tactical Combat Casualty Care [TCCC]
      National Assoication of Emergency Medical Technicians (NAEMT)
      ) may be an ideal drug in this situation because it maintains airway reflexes, ventilation, and blood pressure, but it may result in hallucinations or other altered states.
      • Cohen L.
      • Athaide V.
      • Wickham M.E.
      • Doyle-Waters M.M.
      • Rose N.G.
      • Hohl C.M.
      The effect of ketamine on intracranial and cerebral perfusion and health outcomes: a systematic review.
      MACE, SAC, and other tools for mTBI evaluation can be used if available, but they do not obviate the need for further evaluation in a medical facility.
      • Harmon K.G.
      • Drezner J.A.
      • Gammons M.
      • et al.
      American Medical Society for Sports Medicine position statement: concussion in sport.
      • Ruff R.M.
      • Iverson G.L.
      • Barth J.T.
      • et al.
      Recommendations for diagnosing mild traumatic brain injury: a National Academy of Neuropsychology education paper.
      Chronic medical conditions can develop after any TBI and thus require follow-up. Patients with mild TBI who have returned to baseline can walk out of the field and, if not nauseated, should maintain oral hydration and nutrition, especially if the evacuation will be lengthy.
      • Harmon K.G.
      • Drezner J.A.
      • Gammons M.
      • et al.
      American Medical Society for Sports Medicine position statement: concussion in sport.

      Gerberding JL, Binder S. Report to Congress on mild traumatic brain injury in the United States: steps to prevent a serious public health problem. Available at: https://www.cdc.gov/traumaticbraininjury/pdf/mtbireport-a.pdf. Accessed April 17, 2003.

      • Papa L.
      • Brophy G.M.
      • Welch R.D.
      • et al.
      Time course and diagnostic accuracy of glial and neuronal blood markers GFAP and UCH-L1 in a large cohort of trauma patients with and without mild traumatic brain injury.
      • Ropper A.H.
      • Gorson K.C.
      Clinical practice. Concussion.

      Conclusions

      TBI can readily present in austere environments. Once diagnosed and classified, field-expedient methods should be used to treat the primary injury and prevent any potential secondary injury that may result from hypoxia, hypotension, or increased intracerebral pressure. Prevention of hyperthermia is also important but is less critical in the acute phase of care. Depending on the severity, most casualties with a TBI will need to undergo medical evaluation, but clearly those with moderate or severe TBI should be evacuated as soon as possible for more urgent care.
      Financial/Material Support: None.
      Disclosures: None.

      References

        • Warden D.
        Military TBI during the Iraq and Afghanistan wars.
        J Head Trauma Rehabil. 2006; 21: 398-402
        • Gentile D.A.
        • Morris J.A.
        • Schimelpfenig T.
        • Bass S.M.
        • Auerbach P.S.
        Wilderness injuries and illnesses.
        Ann Emerg Med. 1992; 21: 853-861
        • Stephens B.D.
        • Diekema D.S.
        • Klein E.J.
        Recreational injuries in Washington state national parks.
        Wilderness Environ Med. 2005; 16: 192-197
        • Haider A.H.
        • Saleem T.
        • Bilaniuk J.W.
        • Barraco R.
        • On behalf of the Eastern Association for the Surgery of Trauma Injury Control/Violence Prevention Committee
        An evidence-based review: efficacy of safety helmets in reduction of head injuries in recreational skiers and snowboarders.
        J Trauma Acute Care Surg. 2012; 73: 1340-1347
        • Bauer D.
        • Tung M.L.
        • Tsao J.W.
        Mechanisms of traumatic brain injury.
        Semin Neurol. 2015; 35: e14-e22
        • Montalvo R.
        • Wingard D.L.
        • Bracker M.
        • Davidson T.M.
        Morbidity and mortality in the wilderness.
        West J Med. 1998; 168: 248-254
        • Kronisch R.L.
        • Pfeiffer R.P.
        Mountain biking injuries: an update.
        Sports Med. 2002; 32: 523-537
        • Federiuk C.S.
        • Schlueter J.L.
        • Adams A.L.
        Skiing, snowboarding, and sledding injuries in a northwestern state.
        Wilderness Environ Med. 2002; 13: 245-249
        • Christensen M.L.
        • Jackson C.
        Skiing and snowboarding–related head injuries in the United States: a retrospective analysis from 2004–2010.
        Wilderness Environ Med. 2012; 24: 81
        • Boyd J.
        • Haeglei P.
        • Abu-Laban R.B.
        • Shuster M.
        • Butt J.C.
        Patterns of death among avalanche fatalities: a 21-year review.
        CMAJ. 2009; 180: 507-512
        • McIntosh S.E.
        • Grissom C.K.
        • Olivares C.R.
        • Kim H.S.
        • Tremper B.
        Cause of death in avalanche fatalities.
        Wilderness Environ Med. 2007; 18: 293-297
        • Johnson S.M.
        • Johnson A.C.
        • Barton R.G.
        Avalanche trauma and closed head injury: adding insult to injury.
        Wilderness Environ Med. 2001; 12: 244-247
        • Vargyas G.
        Backcountry skiers, avalanche trauma mortality, and helmet use.
        Wilderness Environ Med. 2015; 27: 181-182
      1. Centers for Disease Control and Prevention. Rates of TBI-related emergency department visits, hospitalizations, and deaths — United States, 2001–2010. Available at: http://www.cdc.gov/traumaticbraininjury/data/rates.html. Accessed April 17, 2017.

        • Stein S.C.
        • Georgoff P.
        • Meghan S.
        • Mizra K.
        • Sonnad S.S.
        150 years of treating severe traumatic brain injury: a systematic review of progress in mortality.
        J Neurotrauma. 2010; 27: 1343-1353
        • Boer C.
        • Franschmann G.
        • Loer S.A.
        Prehospital management of severe traumatic brain injury: concepts and ongoing controversies.
        Curr Opin Anesthesiol. 2012; 25: 556-562
        • Badjatia N.
        • Carney N.
        • Crocco T.J.
        • et al.
        Guidelines for prehospital management of traumatic brain injury 2nd edition.
        Prehosp Emerg Care. 2008; 12: S1-S52
        • Carney N.
        • Totten A.M.
        • O’Reilly C.
        • Ullman J.S.
        • et al.
        Guidelines for the management of severe traumatic brain injury.
        Neurosurgery. 2017; 80: 6-15
        • Huang S.J.
        • Hong W.C.
        • Han Y.Y.
        • et al.
        Clinical outcome of severe head injury using three different ICP and CPP protocol-driven therapies.
        J Clin Neurosci. 2006; 13: 818-822
        • Harmon K.G.
        • Drezner J.A.
        • Gammons M.
        • et al.
        American Medical Society for Sports Medicine position statement: concussion in sport.
        Br J Sports Med. 2013; 47: 15-26
        • Meyer M.
        • Megyesi J.
        • Meythaler J.
        • et al.
        Acute management of acquired head injury part 1: an evidence-based review of non-pharmacological interventions.
        Brain Inj. 2010; 24: 694-705
        • Minardi J.
        • Crocco T.
        Management of traumatic brain injury: first link in chain of survival.
        Mt Sinai J Med. 2009; 76: 138-144
        • Wijayatilake D.S.
        • Jigajinni S.V.
        • Sherren P.B.
        Traumatic brain injury: physiological targets for clinical practice in the prehospital setting and on the Neuro-ICU.
        Curr Opin Anaesthesiol. 2015; 28: 517-524
        • DuBose J.J.
        • Barmparas G.
        • Inaba K.
        • et al.
        Isolated severe traumatic brain injuries sustained during combat operations: demographics, mortality outcomes, and lessons to be learned from contrasts to civilian counterparts.
        J Trauma. 2011; 70 (discussion 16–18): 11-16
        • Weisbrod A.B.
        • Rodriguez C.
        • Bell R.
        • et al.
        Long-term outcomes of combat casualties sustaining penetrating traumatic brain injury.
        J Trauma Acute Care Surg. 2012; 73: 1525-1530
      2. Gerberding JL, Binder S. Report to Congress on mild traumatic brain injury in the United States: steps to prevent a serious public health problem. Available at: https://www.cdc.gov/traumaticbraininjury/pdf/mtbireport-a.pdf. Accessed April 17, 2003.

        • Papa L.
        • Brophy G.M.
        • Welch R.D.
        • et al.
        Time course and diagnostic accuracy of glial and neuronal blood markers GFAP and UCH-L1 in a large cohort of trauma patients with and without mild traumatic brain injury.
        JAMA Neurol. 2016; 73: 551-560
        • Knuth T.
        • Letarte P.B.
        • Ling B.
        • et al.
        Guidelines for the Field Management of Combat Related Head Trauma..
        Brain Trauma Foundation, New York, NY2005
        • Jaffee M.S.
        • Helmick K.M.
        • Girard P.D.
        • Meyer K.S.
        • Dinegar K.
        • George K.
        Acute clinical care and care coordination for traumatic brain injury within Department of Defense.
        J Rehabil Res Dev. 2009; 46: 655-666
        • Ropper A.H.
        • Gorson K.C.
        Clinical practice. Concussion.
        New Engl J Med. 2007; 356: 166-172
        • Ruff R.M.
        • Iverson G.L.
        • Barth J.T.
        • et al.
        Recommendations for diagnosing mild traumatic brain injury: a National Academy of Neuropsychology education paper.
        Arch Clin Neuropsycol. 2009; 24: 3-10
        • Mild Traumatic Brain Injury Committee of the Head Injury Interdisciplinary Special Interest Group of the American Congress of Rehabilitation Medicine
        Definition of mild traumatic brain injury.
        J Head Trauma Rehabil. 1993; 8: 86-87
        • Eastridge B.J.
        • Butler F.
        • Wade C.D.
        • et al.
        Field triage score (FTS) in battlefield casualties: validation of a novel triage technique in a combat environment.
        Am J Surg. 2010; 200: 724-727
        • Mena J.H.
        • Sanchez A.I.
        • Rubiano A.M.
        • et al.
        Effect of the modified Glascow Coma Scale score criteria for mild traumatic brain injury on mortality prediction: comparing classic and modified Glascow Coma Scale model scores of 13.
        J Trauma. 2011; 71: 1185-1193
        • Majdan M.
        • Steyerberg E.W.
        • Nieboer D.
        • Mauritz W.
        • Rusnak M.
        • Lingsma H.F.
        Glasgow coma scale motor score and pupillary reaction to predict six-month mortality in patients with traumatic brain injury: comparison of field and admission assessment.
        J Neurotrauma. 2015; 32: 101-108
        • Chesnut R.M.
        • Marshall S.B.
        • Piek J.
        • Blunt B.A.
        • Klauber M.R.
        • Marshall L.F.
        Early and late systemic hypotension as a frequent and fundamental source of cerebral ischemia following severe brain injury in the Traumatic Coma Data Bank.
        Acta Neurochir Suppl (Wien). 1993; 59: 121-125
        • Chi J.H.
        • Knudson M.M.
        • Vassar M.J.
        • et al.
        Prehospital hypoxia affects outcome in patients with traumatic brain injury: a prospective multicenter study.
        J Trauma. 2006; 61: 1134-1141
        • Warner K.J.
        • Cuschieri J.
        • Copass M.K.
        • Jurkovich G.J.
        • Bulger E.M.
        The impact of prehospital ventilation on outcome after severe traumatic brain injury.
        J Trauma. 2007; 62 (discussion 1336–1338): 1330-1336
        • Andrews P.J.D.
        • Sinclair H.L.
        • Rodriguez A.
        • et al.
        Hypothermia for intracranial hypertension after traumatic brain injury.
        NEJM. 2015; 373: 2403-2412
        • Thompson H.J.
        • Tkacs N.C.
        • Saatman K.E.
        • Raghupathi R.
        • McIntosh T.K.
        Hyperthermia following traumatic brain injury: a critical evaluation.
        Neurobiol Dis. 2003; 12: 163-173
        • Kupersmith J.
        • Lew H.L.
        • Ommaya A.K.
        • Jaffee M.
        • Koroshetz W.J.
        Traumatic brain injury research opportunities: results of Department of Veterans Affairs Consensus Conference.
        J Rehabil Res Dev. 2009; 46: vii-xvi
        • Risdall J.E.
        • Menon D.K.
        Traumatic brain injury.
        Philos Trans R Soc Lond B Biol Sci. 2011; 366: 241-250
        • Stiver S.I.
        • Manley G.T.
        Prehospital management of traumatic brain injury.
        Neurosurg Focus. 2008; 25: E5
        • Blackbourne L.H.
        • Cole J.
        • Mabry R.
        • et al.
        The “silent killer”: hyperventilation in the brain injured.
        US Army Med Dep J. 2008; : 50-55
        • Rockswold G.L.
        • Solid C.A.
        • Paredes-Andrade E.
        • Rockswold S.B.
        • Jancik J.T.
        • Quickel R.R.
        Hypertonic saline and its effect on intracranial pressure, cerebral perfusion pressure and brain tissue oxygen.
        Neurosurgery. 2009; 65: 1035-1041
        • Ropper A.H.
        Hyperosmolar therapy for raised intracranial pressure.
        N Eng J Med. 2012; 367: 746-752
        • Reid M.W.
        • Velez C.S.
        Discriminating military and civilian traumatic brain injuries.
        Mol Cell Neurosci. 2015; 66: 123-128
        • National Assoication of Emergency Medical Technicians (NAEMT)
        PHTLS: Prehospital Trauma Life Support.8th ed. Jones and Bartlett Learning, Burlington, MA2016
        • Brain Trauma Foundation
        • American Association of Neurological Surgeons
        • Congress of Neurological Surgeons.
        Guidelines for the management of severe traumatic brain injury.
        J Neurotrauma. 2007; 24: S1-106
        • Cohen L.
        • Athaide V.
        • Wickham M.E.
        • Doyle-Waters M.M.
        • Rose N.G.
        • Hohl C.M.
        The effect of ketamine on intracranial and cerebral perfusion and health outcomes: a systematic review.
        Ann Emerg Med. 2015; 65: 43-51