Background: The obstetric population is considered at high risk of awareness and recall when undergoing general anaesthesia for caesarean section. In recent years the incidence may have been altered by developments in obstetric anaesthesia.
Methods: A prospective observational study of general anaesthesia for caesarean section was conducted during 2005 and 2006 in 13 maternity hospitals dealing with approximately 49,500 deliveries per annum in Australia and New Zealand. As a component of this study the frequency of recall of intraoperative events was examined using a structured postoperative interview on two occasions.
Results: There were 1095 general anaesthetics surveyed with 47% being performed for urgent fetal delivery. Thiopental was the most common induction agent (83%) with sevoflurane being used for maintenance in 63%. In 32% of cases a depth-of-anaesthesia monitor was used. In 763 cases (70%) there was least one postoperative interview enquiring into dreaming and awareness. There were two cases deemed to be consistent with awareness (incidence 0.26%, CI 0.03-0.9%, or 1 in 382) and three cases of possible awareness.
Conclusion: Awareness with recall of intraoperative events remains a significant complication of obstetric general anaesthesia but was potentially avoidable in all cases detected in this study.