Neurotrauma: Traumatic Brain Injury and Spinal Cord Injury
Traumatic brain injury
Separate primary from secondary injury and prevent the second hit. Avoid hypoxia (SpO2 <90%) and hypotension (SBP <100 mmHg, or <110 in patients 15-49 and over 70). Treat ICP above 22 mmHg and target cerebral perfusion pressure of 60-70 mmHg, remembering that CPP equals mean arterial pressure minus ICP. Use mannitol 0.25-1 g/kg or hypertonic saline for intracranial hypertension; hyperventilation to a PaCO2 of 30-35 mmHg is a bridge for impending herniation only, never a chronic strategy. Steroids are contraindicated. Seizure prophylaxis with phenytoin or levetiracetam is limited to about 7 days and reduces early seizures, not mortality or late epilepsy. Start enteral nutrition early and give VTE prophylaxis once bleeding is stable.
Spinal cord injury
Maintain MAP 85-90 mmHg for about 7 days after acute injury. High-dose methylprednisolone is not recommended. Neurogenic shock combines hypotension with bradycardia; treat with norepinephrine and atropine as needed. High cervical lesions cause respiratory failure and warrant early intubation for vital capacity decline.
Trap: hyperventilating a head-injured patient for hours, or labeling hypotension as neurogenic without excluding hemorrhage elsewhere.
Worked example: MAP 75, ICP 25 gives CPP 50, well below target. Raise MAP to at least 85 mmHg while simultaneously treating the ICP; simply accepting CPP 50 risks ischemia.