Severe Traumatic Brain Injury With Fixed Dilated Pupil (Suspected Brain Herniation)
A patient with a head injury and a blown (non-reactive dilated) pupil should be managed as catastrophic intracranial hypertension or impending herniation requiring immediate resuscitation, urgent neuroimaging, and activation of neurosurgical care pathways. [1,2] Non-contrast head CT should be obtained without delay because focal neurologic deficit is an indication for CT head scan within 1 hour. [2]
Initial Resuscitation and Immediate Stabilization
Assessment of airway patency, ventilation adequacy, and circulation should be performed. [1] Analgesia and sedation should be provided to reduce noxious stimuli that may elevate intracranial pressure while avoiding oversedation that would obscure neurologic assessment. [1] The head of bed should be elevated to >30° with the head kept midline to facilitate cerebral venous drainage. [1] Normothermia should be targeted. [1]
Urgent Imaging and Neurologic Escalation Triggers
A non-contrast head CT scan should be performed when the patient can be safely positioned for diagnostic imaging. [1] CT head should be done within 1 hour after identification of risk factors, including focal neurologic deficit. [2] If the fixed dilated pupil is due to mass effect and herniation physiology, definitive management should proceed without waiting for invasive ICP monitoring. [1]
Medical Temporizing Measures for Herniation Physiology
Hyperosmolar therapy should be initiated as part of first-line herniation management. [1] Mannitol (0.5–1 g/kg IV bolus) or hypertonic saline should be administered for intracranial pressure lowering as Tier One therapy. [1] Serum sodium should be monitored during hypertonic saline infusion and maintained <160 mEq/L during initial Tier One management. [1] A brief course of hyperventilation targeting PaCO2 30–35 mmHg may be considered as a temporizing measure while definitive treatment is pursued. [1] Hyperventilation duration should be limited (<2 hours) because prolonged hyperventilation can result in cerebral ischemia. [1]
Definitive Treatment and Neurosurgical Decision-Making
If intracranial pressure is not controlled and/or clinical signs of herniation do not resolve with Tier One interventions, decompressive surgical options should be considered. [1] For comatose patients with acute subdural hematoma, surgical evacuation should be performed when thresholds are met, including presentations with asymmetric or fixed and dilated pupils. [3] Timing should be expedited because patients with indications for surgery can deteriorate rapidly. [3]
Intracranial Pressure–Directed Escalation Framework
If acute obstructive hydrocephalus is identified on neuroimaging, emergent external ventricular drainage (EVD) should be used. [1] If Tier One interventions control intracranial pressure, repeat head CT should be considered to evaluate for new processes. [1] If Tier One interventions fail to control intracranial pressure, Tier Two interventions should be implemented. [1]
Key Practical Targets During Temporizing Management
Hyperosmolar therapy should aim for intracranial pressure lowering using either mannitol or hypertonic saline. [1] Hyperventilation temporization should target PaCO2 30–35 mmHg and be limited to <2 hours. [1] Hypertonic saline–associated sodium targets should be kept <160 mEq/L during Tier One therapy. [1]
Common Pitfalls to Avoid
Prolonged hyperventilation should be avoided because it can cause or exacerbate ischemic injury via hypocapnia-related cerebral vasoconstriction. [1] Delayed CT imaging should be avoided because focal neurologic deficit is an indication for CT head within 1 hour. [2] Definitive intracranial pressure control should not be deferred when herniation signs do not resolve after Tier One interventions because decompressive surgical options are recommended to be considered in that setting. [1]
Transfer and Care Coordination
Transfer to an appropriate hospital capable of timely CT imaging and neurosurgical management should be arranged when indicated based on CT scan criteria. [2]
Medication Notes in Suspected Herniation Context
Hyperosmolar therapy should use either mannitol or hypertonic saline as Tier One options with comparable efficacy for lowering intracranial pressure. [1]
Relationship to Blood Pressure Status
No blood-pressure–specific adjustment is required solely based on the absence of hypertension in the presence of fixed dilated pupil and suspected herniation physiology. [1]
References
[1] Emergency Neurological Life Support (ENLS) Intracranial Hypertension and Herniation Protocol, last updated May 2022. [2] NICE head injury CT recommendations (NG232), amended 2023. [3] Brain Trauma Foundation Surgical Management of Acute Subdural Hematomas (Surgical management of traumatic brain injury author group), Neurosurgery 2006 (Supplement).