Neuroprotection in head injury
Acute head injury requires early interventions to prevent secondary brain injury from hypoxia, hypotension, raised intracranial pressure (ICP), metabolic disturbance and ongoing haemorrhage.
Priorities in the emergency setting are airway protection and controlled ventilation, optimisation of cerebral perfusion, early measures to limit ICP and bleeding, and timely escalation/transfer. The following is a focused, exam‑relevant practical guide (adult and paediatric principles apply; use weight‑adjusted drugs/doses for children).
Pathophysiological rationale
- Secondary injury is driven by hypoxaemia, hypotension and raised ICP, which all reduce cerebral perfusion and worsen cerebral ischaemia.
- PaCO2 strongly influences cerebral blood flow: hypercapnia causes cerebral vasodilation and increases ICP; hypocapnia causes vasoconstriction and may reduce ICP but risks cerebral ischaemia if sustained.
- Maintaining adequate mean arterial pressure (MAP) preserves cerebral perfusion pressure (CPP) and limits secondary ischaemic injury.
Indications for tracheal intubation and anaesthesia
Intubate promptly when airway protection, oxygenation or ventilation are (or are likely to become) compromised. Key indications (NICE NG232):
- GCS ≤ 8 (intubate and ventilate).
- Loss of protective airway reflexes or inability to manage secretions.
- Abnormal ventilation on blood gases (PaO2 < 13 kPa, PaCO2
> 6.0 kPa).