The Initial Management of Moderate to Severe Traumatic Brain Injury

Introduction

Treatment for traumatic brain injury (TBI) is performed to prevent secondary injury to the brain following the initial injury. The prevention of secondary injury to the brain involves avoiding systemic events such as hypotension, hypoxia, or hyperthermia. The assessment and treatment of military TBI is similar to the treatment of civilian TBI with a greater focus on blast-induced TBIs. With limited resources during wartime, efficient triage and logistics of clinical care delivery take on greater importance. During wartime, many subspecialty surgeons may be tasked to assist with trauma care, outside their area of expertise. The purpose of this chapter is to describe the initial evaluation, management, and stabilization of moderate to severe TBI patients to a non-neurosurgeon surgical audience in a limited resource setting with a focus on prevention of secondary injury.

Evaluation

Evidence from TBI in civilian settings supports the rapid extrication and transport of patients to trauma care facilities. Rapid extrication less than 30 minutes and evacuation of incapacitated patients to a trauma care facility improves outcomes after TBI.¹ In situations where ground transport is unable to transport patients in a timely manner, helicopter based transport has been shown to significantly decrease mortality after severe TBI.² All patients with TBI should first have a structured trauma initial assessment in the field (hopefully included as a separate chapter in this publication). The assessment of the “ABCs,” airway, breathing, and circulation should not be neglected. After the “ABCs”, there should be an evaluation of the patient’s Glasgow Coma Scale (GCS) which is the classic TBI grading score.³ Patients are assessed for eye opening, verbal performance, and motor responsiveness, and these component scores along with the summation should be reported to aid in triage of TBI (see Table 1). In the case of explosive (blast injuries) the possibility that the patient is deaf from the injury and may not respond to auditory commands and stimuli must be considered. A pupil exam assessing the approximate size and reflex of each pupil to light should be performed after ABCs.

All patients with a GCS score of 8 or less are unlikely to protect their airway and are at risk of hypoxemia leading to secondary brain injury. They should be intubated and ventilated in a controlled manner. After securing the airway, the blood pressure should be assessed and hypotension treated with isotonic fluids and hemorrhagic control obtained. If possible, assessment of the pulse oximetry, end tidal CO₂, and blood pressure should be performed frequently. The goals are to avoid hypoxemia (SpO₂<90%), hyperventilation (ETCO₂<35 mm Hg), and hypotension. If there is concern for spine injury, spinal immobilization should be performed to prevent further injury. If the patient shows signs of cerebral herniation from increased intracranial pressure (ICP), which may include dilated nonreactive pupils, asymmetric pupils, extensor posturing, or progressive neurologic deterioration with a decrease in GCS of 2 or more points from initial best score, hyperventilation can be used temporarily at a rate of 20 breaths/minute in an adult as a temporizing measure to constrict blood vessels in the brain and decrease intracranial pressure.

Injured patients secured in this manner should subsequently be transported to a facility which at minimum has x-rays, operative facilities, and surgeons. Ideally, the patients identified with TBI are transported to facilities with specialist neurosurgical care available with additional capabilities of computed tomography (CT) machines and specialist neurosurgical care available.

Management

Secondary Survey

The management of TBI in the military setting follows overall principles that are similar to the management of TBI in the civilian setting.⁴ Once the patient’s “ABCs” have been secured and the patient has been transported to the hospital, a detailed secondary assessment of the patient is necessary. Over half of patients with a severe TBI have other major injuries that require intervention, including pelvic/long bone fracture, major chest injury, abdominal injury, and traumatic spinal cord injury.^5–9 The purpose of the secondary survey is to obtain pertinent historical data about the patient and to treat any missed injuries.

A basic history should be obtained from the patient or the patient’s family, if possible, to include the following information (AMPLE history): Allergy, Medications, Previous medical history of illness, Last meal, and Events related to injury such as the mechanism of injury and or exposure to chemicals, toxins, and/or radiation.

A head-to-toe physical examination should be performed to identify significant injuries which must include an examination of all aspects of the patient. The ABCs should be re-examined during this examination. Vital signs should be re-assessed. The details of the overall secondary survey are described elsewhere (hopefully in a separate chapter?) and the head/face examination is important. The head should be examined for a scalp hematoma, skull depression, or laceration. This involves palpation of the scalp. The facial bony margins should also be palpated to assess for fractures and/or lacerations. The ear examination may reveal blood or clear drainage from the ear concerning for a basilar skull fracture with cerebrospinal fluid leak. The pupillary size and reflex along with the presence of eye movements should be assessed. A nasogastric tube inserted in a blind fashion should be avoided in patients with facial trauma or evidence of basilar skull fracture (such a retro-auricular ecchymosis or bilateral periorbital ecchymosis).

Radiographic and Laboratory Evaluation

After the secondary survey is complete, CT is the initial imaging modality of choice to assess for TBI and trauma to other parts of the body.¹⁰ All patients with moderate to severe TBI (GCS of 13 or below) should be assessed with at least a CT of the head performed without contrast. Patients with gunshot wounds and non-missile penetrating injuries to the brain should have an angiogram, although this does not need to be performed emergently but usually is performed within 3 days of the injury.¹¹ Important findings to note from the CT include the presence of acute hemorrhage and associated mass effect, brain edema, skull fractures, and midline shift. Indications for immediate referral for neurosurgical management/surgery include the following:

1. Acute epidural hematoma with a hematoma volume > 30 mL, GCS of 8 or less with anisocoria, or midline shift > 5 mm
2. Acute subdural hematoma with a thickness > 1 cm, GCS of 8 or less with anisocoria, or midline shift > 5 mm
3. Traumatic intracerebral hemorrhage with hemorrhage volume > 50 mL, GCS of 6-8 with frontal or temporal volume of > 20 mL with midline shift 5 mm or more¹²
4. Symptomatic lesions in the posterior fossa or those with dislocation, obliteration/compression, loss of basal cisterns, or obstructive hydrocephalus on CT¹³

Patients who are not referred immediately for neurosurgical management and are managed medically should have a routine follow-up CT if the patient does not require a more urgent follow-up CT.

1. At our institution, a follow-up CT is typically performed at 6 hours after the initial CT performed
2. Other indications for a more urgent follow up CT include a GCS decline of 2 or more points, development of new neurologic deficit, new pupillary asymmetric, emesis, worsening headache, or a rise in ICP if a ICP monitor is present.

Laboratory studies that are important in patients with moderate to severe TBI include a complete blood count, a pro-time with international normalized ratio (INR), and a basic metabolic panel or electrolyte panel which includes serum sodium, chloride, potassium, BUN, creatinine, glucose, magnesium, calcium, and phosphorous. In the presence of a hemorrhagic traumatic brain injury, we transfuse platelets to maintain a platelet count of 75,000 platelets per microliter or greater, fresh frozen plasma to maintain an INR < 1.5, and packed red blood cells to keep hemoglobin > 7.0 g/dL. As part of the AMPLE history, if the patient is on any anticoagulant medication such as warfarin, these medications should be held and anticoagulation reversed with appropriate reversal agents in the case of a hemorrhagic TBI. Antiplatelets agents such as aspirin and clopidogrel should also be discontinued with hemorrhagic TBI but there is no indication for transfusion of platelets for reversal unless the patient is planned for a neurosurgical procedure.

Critical Care in Moderate to Severe TBI

Patients with severe TBI should be admitted to an intensive care unit (ICU) level of care for close monitoring. The overall goal of the initial management of TBI is to avoid secondary injury from traumatic brain swelling, hypoperfusion, cerebral ischemia, seizures, anemia, fever, and hyperglycemia. Patients who are intubated should be sedated with propofol and/or dexmedetomidine to help control ICP and decrease the metabolic demand of the brain tissues. After resuscitation, maintenance fluids, usually 0.9% normal saline should be given at 35 mL/kg per day. Daily laboratory checks should include a check of the patient’s electrolyte panel and complete blood cell count. The following is a summary of the most recent guidelines for the Management of Severe Traumatic Brain Injury^4,14 and the American College of Surgeons Trauma Quality Program Best Practices Guidelines for Management of TBI (Table 2 summarizing goals of treatment) along with the level of evidence supporting the guideline (Level I = most evidence, Level III = least evidence):

Blood pressure and oxygenation:

1. Monitor blood pressure, and avoid hypotension (systolic blood pressure < 90 mm Hg) – Level II
2. Monitor oxygenation and avoid hypoxia (arterial P_O2 < 60 mm Hg or O₂ saturation < 90%)

ICP monitoring:

1. The placement of an ICP monitor is indicated in all patients who are deemed to be salvageable with a TBI, a GCS less than or equal to 8 after resuscitation, and an abnormal CT scan. Typically, this monitor should be placed by a neurosurgeon.

Prophylactic Hypothermia:

1. Early (within 2.5 hours), short term (48 hours post-injury) prophylactic hypothermia is not recommended to improve outcomes in patients with diffuse TBI. – Level II
2. Prophylactic hypothermia does not decrease mortality rate – Level III

Infection Prophylaxis:

1. Early tracheostomy is recommended to reduce mechanical ventilation days when overall benefit is thought to outweigh complications associated with tracheostomy procedure. – Level II
2. Administer periprocedural antibiotics for intubation to reduce incidence of pneumonia – Level II

Deep Vein Thrombosis Prophylaxis:

1. Mechanical thromboprophylaxis with graduated compression stockings or intermittent pneumatic compression stockings reduce the risk of thrombophlebitis. – Level III
2. Low molecular weight heparin or low-dose unfractionated heparin may be used in combination with mechanical prophylaxis but there is an increased risk of expansion of intracranial hemorrhage.

ICP monitoring and Cerebral perfusion pressure (CPP) threshold (if an ICP monitor is able to be placed):

1. Initiate ICP treatment at an upper threshold of 20 mm Hg. – Level II
2. Cerebral perfusion pressure is the patient’s ICP minus the patient’s mean arterial pressure. The optimal CPP is between 50 – 70 mm Hg. Avoid CPP < 50 mm Hg. – Level III
3. Avoid aggressive maintenance of CPP > 70 mm Hg with fluids and pressors as these increase the risk of acute respiratory distress syndrome.

Nutrition:

1. Feeding patients to attain basal caloric replacement at least by the 5^th day and at most by the 7^th day after injury is recommended to decrease mortality. – Level II
2. Transgastric jejunal feeding is recommended to reduce the incidence of ventilator-associated pneumonia. – Level II

Antiseizure Prophylaxis:

1. Prophylactic anticonvulsants (phenytoin) decrease the incidence of early posttraumatic seizures. – Level II. At our facility we load the patient with 20 mg/kg of phenytoin (fosphenytoin IV formulation), and continue phenytoin 300 mg daily for 7 days post-injury.

Steroids:

1. Steroids do not improve outcome or reduce ICP and the use of high-dose methylprednisolone is associated with increased mortality. – Level I

Hyperventilation:

1. Do not use prophylactic hyperventilation (arterial P_CO2 ≤ 25 mm Hg) to control ICP. – Level II
2. However, hyperventilation may be used as a temporizing measure for reduction of elevated ICP. – Level III

It may be difficult to follow these guidelines in austere settings with limited resources and access to medical equipment and staff. The overall goal of the critical care management of TBI in these settings should be stabilize salvageable patients and minimize the occurrence secondary brain injury while the patients wait for access to neurosurgical care. Postoperative care after neurosurgical intervention for TBI should be directed by the operating neurosurgeon and are beyond the scope of this chapter.

Summary

• This chapter describes the initial evaluation, management, and stabilization of moderate to severe TBI patients to a non-neurosurgeon surgical audience in a limited resource setting with a focus on prevention of secondary injury
• After initial stabilization of airway, breathing, and circulation, patients benefit most by rapid transfer to a facility with imaging, critical care, and operative capability ideally with neurosurgeon specialists.
• A secondary survey should be performed once initial stabilization is performed and a focused history obtained.
• A CT of the head without contrast along with electrolyte panel, complete blood cell count, and pro-time (coagulation studies) are the minimum assessments for TBI.
• Patients with hemorrhagic TBI should have anticoagulation medications stopped and reversed as indicated, and antiplatelets agents stopped.
• The goal of the critical care of the TBI patient is to prevent secondary brain injury due to hypotension, intracranial hypertension, infection, hypoxia, malnutrition, and seizures. In an austere setting, the goal is to keep the patient stable until he or she can be assessed by a neurosurgeon specialist for further care.

References

1. Wilmink, A. B., Samra, G. S., Watson, L. M. & Wilson, A. W. Vehicle entrapment rescue and pre-hospital trauma care. Injury 27, 21–25 (1996).
2. Kim, H. W. & Yun, J.-H. Treatment Experiences of Traumatic Brain Injury Patients using Doctor-Helicopter Emergency Medical Service: Early Data in a Regional Trauma Center. Korean J. Neurotrauma 16, 157–165 (2020).
3. Teasdale, G. & Jennett, B. Assessment of coma and impaired consciousness. A practical scale. Lancet Lond. Engl. 2, 81–84 (1974).
4. Carney, N. et al. Guidelines for the Management of Severe Traumatic Brain Injury, Fourth Edition. Neurosurgery 80, 6–15 (2017).
5. Miller, J. D., Sweet, R. C., Narayan, R. & Becker, D. P. Early insults to the injured brain. JAMA 240, 439–442 (1978).
6. Hills, M. W. & Deane, S. A. Head injury and facial injury: is there an increased risk of cervical spine injury? J. Trauma 34, 549–553; discussion 553-554 (1993).
7. Kennedy, F. R., Gonzalez, P., Beitler, A., Sterling-Scott, R. & Fleming, A. W. Incidence of cervical spine injury in patients with gunshot wounds to the head. South. Med. J. 87, 621–623 (1994).
8. Gbaanador, G. B., Fruin, A. H. & Taylon, C. Role of routine emergency cervical radiography in head trauma. Am. J. Surg. 152, 643–648 (1986).
9. O’Malley, K. F. & Ross, S. E. The incidence of injury to the cervical spine in patients with craniocerebral injury. J. Trauma 28, 1476–1478 (1988).
10. Stiell, I. G. et al. The Canadian CT Head Rule for patients with minor head injury. Lancet Lond. Engl. 357, 1391–1396 (2001).
11. Benzel, E. C. et al. Civilian craniocerebral gunshot wounds. Neurosurgery 29, 67–71; discussion 71-72 (1991).
12. Bullock, M. R. et al. Surgical management of traumatic parenchymal lesions. Neurosurgery 58, S25-46; discussion Si-iv (2006).
13. Bullock, M. R. et al. Surgical management of posterior fossa mass lesions. Neurosurgery 58, S47-55; discussion Si-iv (2006).
14. Brain Trauma Foundation, American Association of Neurological Surgeons, & Congress of Neurological Surgeons. Guidelines for the management of severe traumatic brain injury. J. Neurotrauma 24 Suppl 1, S1-106 (2007).