During craniotomy for a supratentorial tumour, which anaesthetic technique most reliably reduces intracranial pressure (ICP) while maintaining cerebral perfusion pressure (CPP)?
- A Deep halothane anaesthesia with controlled hypoventilation
- B High-dose sevoflurane (>2 MAC) with normocapnia
- C Total intravenous anaesthesia (TIVA) with propofol and remifentanil; moderate hyperventilation to PaCO₂ 30–35 mmHg ✓
- D Nitrous oxide combined with high-dose fentanyl for brain relaxation
Explanation
TIVA with propofol reduces cerebral metabolic rate of oxygen (CMRO₂) and provides cerebral vasoconstriction, thereby decreasing cerebral blood volume and ICP — superior to volatile agents at equipotent doses. Remifentanil provides analgesia without affecting ICP. Mild hyperventilation (PaCO₂ 30–35 mmHg) causes cerebral vasoconstriction reducing CBV and ICP; PaCO₂ below 25 mmHg risks ischaemia. Volatile agents (halothane, sevoflurane >1 MAC) cause cerebral vasodilation and dose-dependent ICP elevation. N₂O increases CMRO₂ and expands pneumocephalus; it is avoided in neuroanaesthesia.
Reference: Morgan & Mikhail's Clinical Anesthesiology, 6th ed.
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