Modification of nitrous oxide induced intracranial hypertension by prior induction of anesthesia

Abstract

A 22 yr old man abruptly came in coma due to an arteriovenous malformation in the brain stem. Continuous drainage of CSF was necessary to maintain intracranial pressure (ICP) below 20-25 mm Hg. He was scheduled for ventricular peritoneal CSF shunt. He got 10 mg of pancuronium and was ventilated with 100% oxygen. ICP stabilized after 10 min. on 15 mm Hg. Introduction of nitrous oxide (7 l N2O to 2 l of oxygen) made the ICP rise to 35 mm Hg. When again 100% O2 was administered ICP fell to its base line value of 15 mm Hg. After i.v. administration of 20 mg diazepam and 150 mg thiopental, the administration of nitrous oxide did not cause any rise in ICP. The results are discussed.