Acute and Critical Care Management of Brain Injury
Core concepts
Understand the Monro-Kellie doctrine and intracranial pressure (ICP) management: head-of-bed elevation, sedation, osmotic therapy (hypertonic saline, mannitol), CSF diversion, and decompressive surgery for refractory elevation. Know cerebral perfusion pressure (CPP) = MAP − ICP and the rationale for blood pressure targets. Understand that hypotension and hypoxia are the two most modifiable secondary insults - avoid both. Know the role of seizure prophylaxis (typically 7 days after severe TBI, not indefinite), temperature control, and glucose/sodium management. Recognize indications for surgical decompression (e.g., expanding hematoma, midline shift, refractory ICP). Understand that steroids are contraindicated in TBI (increased mortality) but used in some tumor-related edema.
Traps
Questions test whether you know steroids worsen TBI outcomes (CRASH trial). Do not overuse prophylactic anticonvulsants beyond the early window. Distinguish hyperventilation (brief, bridge to definitive care; risks ischemia) from sustained therapy. Remember that mannitol requires adequate renal function and can cause rebound edema.
Rule of thumb
"Fix the physiology first": oxygenation, blood pressure, then ICP/CPP. Sustained hyperventilation is a rescue, not a routine.
Worked example
A severe TBI patient has ICP 25 and MAP 70 → CPP 45, below target. Raise MAP or lower ICP; CPP = MAP − ICP governs the intervention.