Total intravenous anaesthesia using low-dose ketamine infusion for caesarean section. A comparison with a standard inhalation anaesthetic technique.

Anaesthesia was induced in 65 parturients undergoing elective caesarean section with thiopentone 3,5 mg/kg and suxamethonium 1,5 mg/kg intravenously. For anaesthetic maintenance patients were randomly divided into two groups. Patients in group A were ventilated with 50% nitrous oxide in oxygen, supplemented with 0,6-0,8% enflurane and 50 mg pethidine given intravenously after delivery. Group B patients were ventilated with 50% oxygen in nitrogen and received a continuous intravenous infusion of ketamine (70 micrograms/kg/min), with 5 mg diazepam intravenously following delivery. All patients received intravenous alcuronium 0,2 mg/kg. Inspired oxygen concentration (0,5) and end-tidal carbon dioxide tensions (4,0-5,0 kPa), were standardized. Despite a high incidence of predelivery hypotension in group A but not in group B, the fetal acid-base status, materno-placento-fetal exchange and immediate clinical state of the neonates were comparable. Neonatal neurobehavioural assessment scores assessed 2-4 hours after birth favoured the inhalation technique, but this difference disappeared at 24 hours. A higher incidence of factual recall in group B (14,3% v. 7,4%), frequently painful (10,7% v. 0%), the reporting of unpleasant dreams and a lack of significant postoperative analgesia makes the ketamine infusion technique unsatisfactory.