Secondary Gains: Advances in Neurotrauma Management

Key points

Neurologic injuries

Intracranial pressure (ICP) is a measure of several components of the CNS: brain parenchyma, blood, and cerebrospinal fluid (CSF).2, 10, 11 Any increase in one value mandates a decrease in another.10, 11, 12, 13, 14, 15, 16, 17 Once compensatory methods are exhausted, further volume leads to drastic increases in ICP. Cerebral perfusion pressure (CPP) is related to ICP, and an increase in ICP may decrease cerebral perfusion. The goal of resuscitation and management in neurotrauma is to ensure an

Spinal cord injury

Blunt spinal injury is due to cord compression, spinal distraction, or shearing with vertebral and disk damage.2, 6, 7, 8, 9 Owing to trauma, the spinal canal may be compromised, leading to spinal artery blood flow obstruction, resulting in further ischemia.2, 7, 8, 9 Penetrating injury involves spinal cord laceration or transection, which is rare. The cervical and thoracic regions are affected most commonly if penetrating injury does occur.6, 7, 8, 9

What are secondary injuries, and are they dangerous?

Neurotrauma begins a cascade of inflammatory cytokines that worsens ischemia and edema, resulting in secondary injury and poor patient outcomes.10, 11, 23, 24 The following elements are believed to be linked to the development of secondary injury and provide rational targets for neuroresuscitation in the ED:

• •

  Hypotension: Present in 30% of patients, resulting in higher likelihood of poor outcome (odds ratio, 2.67).25, 26, 27, 28, 29

• •

  Hypoxia: Present in 50% of patients, resulting in a higher

Physiologic goals

Hypotension is associated with increased morbidity and mortality in TBI. A CPP goal of 50 to 70 mm Hg should be used, although without direct monitoring of cerebral tissue this is difficult in the ED. Per the Brain Trauma Foundation, a systolic blood pressure of at least 100 mm Hg (ages 50–69) and 110 mm Hg for those 15 to 49 years or older than 70 years is a better target than CPP. Otherwise, a MAP of 70 mm Hg is advised.11, 27, 28, 29 However, other authors recommend a MAP of 80 mm Hg as

Evaluation and management

Initial management should focus on airway, breathing, circulation, disability, and exposure in the primary survey, while maintaining spinal precautions.27, 28, 31 Considerations for ED care are discussed in Box 2. Markers of increased mortality and morbidity include hypoxia, hypotension, advanced age, poor admission GCS motor score, pupillary function, and intracranial hypertension.2, 11, 23, 25, 26, 27, 28 A GCS of less than 8 may require intubation for airway protection. Other indications

Tiers of management of intracranial pressure

ICP and neurologic resuscitation are aimed at restoring and maintaining cerebral metabolism through sufficient oxygen and glucose delivery.10, 11, 16, 17, 23, 26, 27, 28, 35, 36, 39 A tiered approach may be used for ICP management. Close evaluation of clinical herniation is warranted. These signs include unilateral pupillary dilation, acute unilateral weakness, decreased mental status, posturing, and Cushing’s triad (hypertension, bradycardia, and changes in respiratory pattern). The following

How should the airway be managed?

Airway protection and blood pressure support for severe neurotrauma are priorities. Rapid sequence intubation with in-line stabilization of the cervical spine may be necessary. First pass success is vital to avoid the adverse effects of hypoxia and avoid repeated laryngeal stimulation.11, 31 Considerations of intubation are discussed in Box 3. Adequate preoxygenation with apneic oxygenation and head of bed elevation are important in preventing hypoxia.48, 49

Patients may experience hypertensive

How should you treat hypotension?

A single systolic blood pressure reading of less than 90 mm Hg is a predictor of worse outcome in TBI, whereas MAP greater than 80 mm Hg is preferable in the resuscitation phase.25, 29, 36, 41, 43, 44, 45, 75, 76 The multitrauma patient with head trauma who is hypotensive presents a challenge. Permissive hypotension to reduce the risk of clot disruption in penetrating trauma may be beneficial. However, in the patient with moderate to severe head trauma, permissive hypotension is

Are vasopressors needed?

The patient with shock from a neurogenic source often requires the use of IV fluid and vasopressors.8, 76, 79, 80, 81 Patients with neurogenic shock with hypotension and bradycardia should receive IV fluids before vasopressors. Loss of sympathetic tone is common within the first week of injury.8, 9, 76, 79, 80, 81, 82 A goal MAP of 85 mm Hg is recommended by the American Association of Neurological Surgeons and Congress of Neurological Surgeons, which is different other conditions in

When should you speak with the neurosurgeon?

Neurosurgical consultation is advised for a GCS of 13 or less, seizure, lateralizing findings on examination, abnormal head CT scan, signs of CSF leak, basilar skull fracture, penetrating injury, cerebrovascular injury, or C-spine injury.2, 11, 27, 28, 75, 82, 83 Rapid neurosurgical team involvement is associated with improved outcomes.27, 28, 83

What hyperosmolar therapies are available, and which is the most effective?

Hyperosmolar therapy is a staple of neurotrauma management through reduction in ICP, decreased brain water and edema, and improved cerebral blood flow. This combination ultimately results in improved cerebral perfusion.2, 11, 41, 77, 78, 84, 85, 86, 87 Any findings suggestive of increased ICP such as pupillary change, decrease in the GCS of 2 or more points, or posturing warrants empiric treatment with 20% mannitol 0.25 to 1.00 g/kg IV as a rapid infusion over 5 minutes or 3% NaCl 150 to 250 mL

When is monitoring of intracranial pressure required?

Placement of an ICP monitor is difficult in an ED, and it requires consultation with a neurosurgeon.2, 11, 27, 102 However, these monitors may assist in management, because prolonged intracranial hypertension is associated with poor outcome specifically in patients with a GCS of less than 8.2, 26, 27, 102, 103 Indications are discussed further in Box 4. Of note, patients with any abnormality on the head CT scan have an increased risk of intracranial hypertension that approaches 63%, compared

Is there a bedside technique to evaluate for increased intracranial pressure?

Ocular ultrasound imaging can measure the optic nerve sheath diameter (ONSD), which correlates closely with ICP.105, 106, 107, 108 The normal optic nerve sheath is up to 5 mm in diameter, which increases with elevated ICP. To measure the ONSD, a high-resolution linear array probe should be used, with a large amount of water-soluble transmission gel applied to the patient’s closed eyelid. The depth should be adjusted so the eye fills the screen. Both eyes should be scanned in sagittal and

When is surgery required?

Surgical management of TBI includes repair of depressed skull fracture and evacuation of intracranial mass.109, 110, 111, 112, 113, 114 Decompressive craniectomy is indicated for refractory intracranial hypertension. Indications for specific injuries are shown in Table 3. However, decompressive craniectomy may not improve functional outcome while decreasing ICP.¹¹³ The DECRA trial (DEcompressive CRAniectomy) evaluated bifrontotemporal decompression in randomized patients with severe TBI failing

Is hypothermia effective in neurotrauma?

Hypothermia may act as a neuroprotectant.2, 11, 27, 121, 122, 123 To date, no benefit is present for hypothermia in patients with neurotrauma in mortality or neurologic outcome in several metaanalyses.121, 122, 123 However, intracranial hypertension is reduced with hypothermia.121, 122, 123 Targeted management of temperature reduces the cerebral metabolic rate, the release of excitatory neurotransmitters, and blood–brain barrier destruction.124, 125, 126 Hypothermia remains experimental, and

Should you reverse coagulopathy with traumatic intracerebral hemorrhage?

Close to one-third of patients who experience severe TBI develop a coagulopathy, associated with poor neurologic outcomes and mortality. This coagulopathy can be due to patient medications, but acute neurotrauma can result in coagulopathy through systemic release of tissue factor, which lead to intravascular coagulation and consumptive coagulopathy.127, 128 Tests such as the prothrombin time, partial thromboplastin time, International Normalized Ratio, and thromboelastography can be used to

Is there any role for a pharmacologically induced coma?

Barbiturates such as phenobarbital may be used to reduce ICP if refractory to other treatment.11, 27, 41, 132, 133, 134, 135, 136, 137 The mechanism of action is thought to be due to suppression of cerebral metabolism, modification of vascular resistance, and decrease of neuronal excitotoxicity.133, 134 This therapy is associated with multiple side effects, including hypotension, gastroparesis, and immunosuppression.135, 136 Close to 1 in 4 patients experiences hypotension, and a 2012 Cochrane

Corticosteroids used to be recommended, but what about now?

Corticosteroids were first used in the 1960s for cerebral edema treatment. Researchers hypothesized that steroids reduced CSF production, altered vascular permeability, and decreased free radicals.138, 139 However, the CRASH trial (Corticosteroid Randomisation after Significant Head Injury) suggests worse outcomes for patients with TBI given steroids.¹⁴⁰ This trial of 10,008 patients from 49 countries demonstrated increased mortality in the group given steroids.¹⁴⁰ For spinal injury, the NASCIS

Should seizures be treated in neurotrauma?

Seizures occur in up to 30% of TBI patients and 50% of patients with penetrating head injury.2, 11, 27, 41 Early posttraumatic seizures occur within 7 days of injury and late seizures beyond 7 days. Active seizure requires immediate treatment, because prolonged seizures increase secondary brain injury and increase the ICP.2, 11, 27, 28, 41 Benzodiazepines are a first-line treatment for active seizures. Phenytoin may reduce the incidence of early seizure, but not delayed seizure.¹⁴⁶

Does tranexamic acid have a place in neurotrauma?

Tranexamic acid (TXA) has demonstrated usefulness and efficacy in oral bleeding, epistaxis, postpartum hemorrhage, and major trauma.149, 150, 151, 152 The CRASH-2 study found improved measures of coagulopathy and survival in patients requiring massive transfusion if given within the first 3 hours after an injury.¹⁴⁹ However, the effects of TXA in neurotrauma is under study. For patients with nontraumatic intracranial hemorrhage (subarachnoid hemorrhage and intracerebral hemorrhage), limited

When is burr hole evacuation required, and how is it completed?

Ideal treatment for extraaxial hematoma is provided by a neurosurgeon, but in remote locations this is not always possible.153, 154, 155, 156 Performing an emergency burr hole can be successful, and there have been several advances in the safety of this technique. This procedure should only be attempted in cases of raised and deteriorating ICP refractory to medical management when neurosurgical intervention is not readily available.153, 154, 155, 156 Contraindications include a GCS of greater

What is neurogenic shock, and is it different from spinal shock?

Neurogenic shock is a form of distributive shock found in spinal cord injuries above T6, resulting in loss of sympathetic tone to the systemic vasculature.75, 76, 79, 80, 81, 82 This leads to hypotension, vasodilatation, and bradycardia with increased vagal tone. Bradycardia should trigger the consideration for neurogenic shock, although this entity may be complicated by concomitant hemorrhage.75, 76, 79, 80, 81, 82 Providers should always consider hemorrhagic shock in the patient with

What are the pitfalls in evaluation and management?

A variety of pitfalls are present in neuroresuscitation. These pitfalls include failure to obtain adequate neurologic examination before sedation and paralysis, inadequate postintubation sedation and analgesia, and failure to achieve the neuroresuscitation targets as described. Various trials have evaluated the use of other medications that target aspects of neurotrauma. Progesterone IV has not demonstrated efficacy in 2 separate trials and should not be used.159, 160

Hyperventilation was

What affects prognosis?

Patient outcome depends on multiple factors, including arrival GCS, CT abnormalities, age, other injuries, hypotension, hypoxemia, pyrexia, elevated ICP, decreased CPP, decreased pupillary function, and coagulopathy. Biomarkers have been evaluated including alpha-synuclein, S-100Beta protein, and neuro-specific enolase of the blood or CSF.166, 167, 168 These markers require further validation before use. A GCS of less than 8 is associated with a 30% mortality, and only 25% are functionally

Newer directions

Care of patients with neurotrauma is now a well-defined specialty. Specialized neurocritical care teams reduce duration of stay and in-hospital mortality.2, 83 Specialized imaging include MRI and real-time monitoring of further cerebral physiology such as transcranial Doppler ultrasound imaging may provide benefit, although further studies are needed.174, 175

A number of assessment scores are available, often dependent on the physician and institution. The GCS is a 15-point score composed of

Summary

Neurotrauma is the leading cause of death in North America in those between 1 and 45 years of age. Primary and secondary injuries result in severe morbidity and mortality. Neurotrauma includes head contusion, epidural hematoma, subdural hematoma, subarachnoid hemorrhage, diffuse axonal injury, skull fracture, and traumatic spinal cord injury. CPP requires adequate cerebral blood flow. Evaluation and management in the ED entails initial stabilization and resuscitation while assessing neurologic