Neurologic and Neurosurgical Disorders
What matters most
Neurocritical care questions hinge on cerebral perfusion, seizure control, and time-critical stroke decisions.
- ICP/CPP: CPP = MAP − ICP; target roughly 60–70 mmHg. Raise MAP with pressors or lower ICP with head elevation, sedation, CSF drainage, osmotic therapy.
- Osmotic therapy: mannitol 0.5–1 g/kg or hypertonic saline bolus; monitor sodium and osmolality; hypertonic saline is preferred in hypotension because mannitol causes diuresis.
- Status epilepticus ladder: benzodiazepine first (lorazepam or midazolam), then a load of levetiracetam, valproate, or fosphenytoin; refractory cases need continuous infusion and EEG monitoring.
- Aneurysmal subarachnoid hemorrhage: oral or enteral nimodipine 60 mg every 4 hours for 21 days (never IV), early aneurysm securing, watch for hydrocephalus and vasospasm.
- Acute ischemic stroke: thrombolysis within the accepted window if no contraindication, BP under 185/110 before lysis and under 180/105 after; thrombectomy for large vessel occlusion.
- TBI: avoid hypoxia and hypotension; maintain normocapnia unless herniation is impending.
Traps
Giving nimodipine intravenously; lowering blood pressure aggressively in ischemic stroke before lysis is considered; using hyperventilation as a chronic therapy; giving phenytoin rapidly without cardiac monitoring; forgetting that fever and hyperglycemia worsen outcomes.
Worked example
ICP 22 mmHg, MAP 70 mmHg: CPP = 48 mmHg, too low. Options are to raise MAP with norepinephrine or lower ICP with sedation, osmotherapy, or drainage - not to accept 48.
Rule of thumb
CPP = MAP − ICP. If CPP is low, check whether the problem is pressure in or pressure out.