Clinical meaning
Cerebral Blood Flow (CBF) is autoregulated. When ICP rises, MAP must rise to maintain CPP (CPP = MAP - ICP). If ICP exceeds MAP, perfusion stops. Brain herniation (Uncal, Tonsillar) causes mechanical compression of the brainstem.
Diagnosis & workup
Diagnostics & workup: - Order CT head without contrast STAT for acute changes - Order ICP monitoring (EVD or intraparenchymal bolt) for GCS ≤ 8 - Order continuous EEG for seizure monitoring - Order ABG to manage PaCO2 (target 35-40 mmHg, or 30-35 for acute herniation) - Order serum osmolality to guide hyperosmolar therapy - Order serum sodium every 4-6 hours during hypertonic saline infusion - Order MRI brain when stable to evaluate extent of injury - Order cerebral perfusion studies (CT perfusion or TCD) for vasospasm
Risk factors: - Traumatic brain injury (GCS ≤ 8) - Intracerebral hemorrhage - Large territory ischemic stroke - Brain tumor with mass effect - Meningitis/encephalitis - Status epilepticus - Hepatic encephalopathy (grade III-IV) - Post-craniotomy