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  • Chapter 8

    TRAUMATICBRAIN INJURY

    Contributing AuthorsScott A. Marshall, MD

    Randy Bell, MD Rocco A. Armonda, MD, LTC, MC, US Army Eric Savitsky, MD Geoffrey S.F. Ling, MD, PhD, COL, MC, US Army

  • All figures and tables included in this chapter have been used with permission from Pelagique, LLC, the UCLA Center for International Medicine, and/or the authors, unless otherwise noted.

    Use of imagery from the Defense Imagery Management Operations Center (DIMOC) does not imply or constitute Department of Defense (DOD) endorsement of this company, its products, or services.

    Disclaimer The opinions and views expressed herein belong solely to those of the authors. They are not nor should they be implied as being endorsed by the United States Uniformed Services University of the Health Sciences, Department of the Army, Department of the Navy, Department of the Air Force, Department of Defense, or any other branch of the federal government.

  • Traumatic Brain Injury | 345

    Table of Contents

    Introduction ........................................................................................................ 347

    Pathophysiology of Traumatic Brain Injury ............................................................ 348

    Closed Head Injury .............................................................................................. 351

    Mild, Moderate, and Severe Brain Injury ................................................................ 351Blast Traumatic Brain Injury ..........................................................................................353Second Impact Syndrome ................................................................................................354Focal versus Diffuse TBI ...................................................................................................355Epidural and Subdural Hematomas ................................................................................355

    Subdural Hematomas ........................................................................................................355Epidural Hematomas .........................................................................................................356

    Traumatic Intracerebral Hemorrhage ............................................................................357Herniation Syndromes .....................................................................................................358

    Subfalcine, Central, and Uncal Herniation .......................................................................358Transcranial and Paradoxical Herniation ..........................................................................360Tonsillar and Upward Herniation .....................................................................................360

    Penetrating Traumatic Brain Injury ....................................................................... 361Infection and Cerebrospinal Fluid Leaks .........................................................................362Neuroimaging in Penetrating TBI ....................................................................................362

    Traumatic Brain Injury Management ..................................................................... 363Initial Management (Primary Survey).............................................................................363

    Airway and Breathing Management ..................................................................................363Head Position .....................................................................................................................366Secondary Survey...............................................................................................................366

    TBI Management Guidelines and Options ......................................................................367Airway Management and Ventilation ................................................................................367Role of Hyperventilation ...................................................................................................367Hemodynamic Management .............................................................................................368Goals for ICP Management ...............................................................................................369Intracranial Pressure and External Ventricular Drains .....................................................369Hypertonic Saline and Other Medical ICP Management Options ..................................370

    Role of Mannitol ............................................................................................................370Hypertonic Saline (HTS) ................................................................................................372

    Other Pharmacologic Agents to Reduce ICP ....................................................................373Induced Hypothermia .......................................................................................................374Decompressive Craniectomy .............................................................................................374

    Current Use of Decompressive Craniectomy with Intractable Intracranial Hypertension ..........375Anticonvulsant Use in TBI ................................................................................................375Critical Care and Air Evacuation ......................................................................................376

  • 346 | Traumatic Brain Injury

    Other Management Considerations ....................................................................... 377

    Summary ............................................................................................................ 378

    References .......................................................................................................... 379

  • Traumatic Brain Injury | 347

    Introduction

    Traumatic brain injury (TBI) occurs whenever a physical force that impacts the head leads to neuropathology. This can be as simple as a minor laceration from a small fragment to decapitation. Of all the injuries to the head that are concerning, the most worrisome is TBI.

    Traumatic brain injury is a leading cause of death and disability from trauma. In the United States (US), more than 50,000 patients die from TBI each year, accounting for almost one-third of all civilian trauma-related deaths.1 Most of these injuries are a direct result of falls, motor vehicle accidents, and assaults. The cost for direct TBI medical care is estimated at more than $50 billion per year.2,3 The majority of victims of both civilian and military TBI are young male adults.4,5 The societal burden of TBI is staggering. Traumatic brain injury accounts for the greatest number of years lived with trauma-related disability.5 Many victims of TBI are young and thus require extended rehabilitation and reintegration. Many will likely require medical discharge from the armed forces. The young age of many TBI victims is especially unfortunate as these patients may no longer be productive members of society at a time in their life when their potential contributions are greatest.4

    Figure 1. A US casualty who sustained explosive blast TBI.

  • 348 | Traumatic Brain Injury

    Traumatic brain injury is a common battle-related injury. In the wars of the 20th century, approximately 15 to 20 percent of injuries incurred in combat involved the head.6 Evidence suggests that this is also the case for casualties sustained in the recent wars, Operation Enduring Freedom (OEF) in Afghanistan and Operation Iraqi Freedom (OIF) (Fig. 1).7 Some have speculated that a greater percentage of patients from these recent wars have suffered head injury than in prior conflicts.8 This increase in prevalence is thought to be a paradoxical consequence of the remarkable improvements in medical care and protective body armor.9 These advances have resulted in the lowest killed-to-wounded ratio in modern warfare.10 The paradox is that with more wounded warfighters surviving, more are left with severe wounds, especially to less protected anatomical regions such as head and extremities. Thus, TBI, traumatic amputations, and other such injuries are disproportionally represented. Specifically, TBI resulting from explosive blast has become very prominent in the past several years.11,12,13

    Traumatic brain injury is a common battle-related injury. Treatment goals in the first 72 hours of care for the injured patient with TBI are to provide clinical stability, arrest any element of ongoing injury, preserve neurological function, and prevent medical complications secondary to multisystem trauma.

    With advances in battlefield or prehospital clinical management of combat casualties, the outcomes of severe conditions such as TBI have improved. Critical elements include improved training and resources for far-forward medical providers, a highly efficient modern triage and evacuation system, and dramatically shortened length of stay in-theater prior to definitive care in the US.14 There is evidence that the vast majority of fatal injuries incurred in combat result from injuries that would be nonsurvivable in any setting.15 Thus, those who can be saved are being saved, even under the austere conditions of war. However, as long as there are survivors left with chronic disabilities, there is opportunity for improvements in medical care.

    Treatment goals in the first 72 hours of care for the injured patient with TBI are to provide clinical stability, arrest any element of ongoing injury, preserve neurological function, and prevent medical complications secondary to severe tr