Neurocritical Care: ICP, SAH and Status Epilepticus
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Direct answer
Secondary brain injury is preventable where the primary insult is not — so neurocritical care holds intracranial pressure below 22 mmHg, cerebral perfusion pressure between 60 and 70 mmHg, PaCO2 normal, sodium above 140 mmol/L, temperature and glucose normal, and seizures treated or pre-empted. An elevated ICP is managed in tiers from head position and sedation through hyperosmolar therapy to decompression, subarachnoid haemorrhage gets nimodipine and euvolaemia, and status epilepticus gets benzodiazepines then a second-line antiseizure drug without delay.
What you must remember
- Brain Trauma Foundation fourth edition: treat ICP above 22 mmHg; target CPP 60 to 70 mmHg — higher pressures flood the lungs, lower ones starve the brain.
- Prophylactic antiseizure medication for the first seven days after traumatic brain injury; no longer-term prophylaxis.
- Hyperosmolar therapy: mannitol 0.25 to 1 g per kg or 3 per cent saline bolus (about 250 mL) — hypertonic saline may edge out mannitol for ICP control, and mannitol loses effect above serum osmolality of about 320 mOsm/kg.
- Therapeutic hypothermia in TBI is dead; normothermia with active pyrexia control is standard, and targeted temperature management 32 to 36 degrees Celsius applies after cardiac arrest.
- Subarachnoid haemorrhage: oral nimodipine 60 mg every four hours for 21 days, euvolaemia (triple-H therapy abandoned), transcranial Doppler for vasospasm peaking days 4 to 10, and induced hypertension once delayed cerebral ischaemia appears.
- Status epilepticus: lorazepam 0.1 mg per kg intravenously (or intramuscular midazolam 10 mg per RAMPART), then a second-line agent — fosphenytoin 20 mg phenytoin-equivalents per kg, levetiracetam 60 mg per kg, or valproate 40 mg per kg, equivalent per ESETT.
- Non-convulsive status is found only by looking: continuous EEG for any unexplained coma, and neuroprognostication after arrest is multimodal, deferred to at least 72 hours off sedation.
Climbing the ICP ladder
A 32-year-old, day two after a severe TBI, develops anisocoria on an external ventricular drain reading 28 mmHg. Work upward in tiers and stop when the number falls. Tier zero: head at 30 degrees and midline, sedation deepened, PaCO2 held 35 to 40 mmHg, pyrexia treated, hyponatraemia corrected toward 140 to 145 mmol/L with hypertonic saline rather than waterlogged with plain saline. Tier one: drain cerebrospinal fluid via the ventriculostomy — the fastest definitive litre in medicine — and give a 3 per cent saline bolus. Tier two: if pressure stays above 22 mmHg, a short infusion of neuromuscular blockade for synchrony, CSR drainage repeated, and hyperosmolar therapy continued with sodium targeted around 145 to 150 mmol/L. Tier three: decompressive craniectomy for refractory elevation as a last-resort conversation — DECRA warned against early bifrontal surgery for moderate elevations, RESCUEicp established unilateral surgery as an ultimate option with survival bought at the cost of severe disability in a proportion of survivors. Alongside the ladder runs the search for a surgical lesion — a clot that needs the operating theatre outranks every tier above.
Where students slip
The recurring errors are physiology-shaped. Prophylactic hyperventilation to PaCO2 of 30 causes the cerebral vasoconstriction it once sought to exploit — it is a temporising manoeuvre for impending herniation only. Steroids in TBI increase mortality and are contraindicated; stating that plainly earns marks. Nimodipine is enteral, 60 mg every four hours for 21 days — intravenous nimodipine is a historical hazard, and confusing the route is a genuine fail-grade slip. CPP pushed above 70 recreates the fluid-overload ARDS of old protocols. And the modernity trap: quoting a single "72-hour unmapped EEG" as prognostication — the answer is multimodal (examination, EEG, SSEP N20, imaging, biomarkers) at 72 hours or later, off sedation.
Frequently asked questions
What ICP and CPP targets does the Brain Trauma Foundation set?
Treat intracranial pressure above 22 mmHg; maintain cerebral perfusion pressure 60 to 70 mmHg.
Mannitol or hypertonic saline for raised ICP?
Either as bolus — mannitol 0.25 to 1 g per kg capped by osmolality near 320 mOsm/kg; 3 per cent saline about 250 mL with sodium targeted to the upper-normal range, with growing preference in many units.
What is the nimodipine regimen after subarachnoid haemorrhage?
Oral 60 mg every four hours for 21 days, started early, alongside euvolaemia and monitoring for delayed cerebral ischaemia from day 4 to 10.
What is the second-line drug in status epilepticus?
Any one of fosphenytoin 20 mg phenytoin-equivalents per kg, levetiracetam 60 mg per kg, or valproate 40 mg per kg — ESETT found them equivalent after benzodiazepines.
Is therapeutic hypothermia used in traumatic brain injury?
No — trials were negative; maintain normothermia and treat pyrexia. Targeted temperature management 32 to 36 degrees Celsius applies after cardiac arrest.
When is neuroprognostication performed after cardiac arrest?
Not before 72 hours, off sedation, using multiple modalities — examination, EEG, somatosensory evoked potentials, imaging and biomarkers together.