General anaesthesia for obstetric surgery has distinct characteristics that may contribute towards a higher risk of accidental awareness during general anaesthesia. The primary aim of this study was to investigate the incidence, experience and psychological implications of unintended conscious awareness during general anaesthesia in obstetric patients. From May 2017 to August 2018, 3115 consenting patients receiving general anaesthesia for obstetric surgery in 72 hospitals in England were recruited to the study. Patients received three repetitions of standardised questioning over 30 days, with responses indicating memories during general anaesthesia that were verified using interviews and record interrogation. A total of 12 patients had certain/ probable or possible awareness, an incidence of 1 in 256 (95%CI 149-500) for all obstetric surgery. The incidence was 1 in 212 (95%CI 122-417) for caesarean section surgery. Distressing experiences were reported by seven (58.3%) patients, paralysis by five (41.7%) and paralysis with pain by two (16.7%). Accidental awareness occurred during induction and emergence in nine (75%) of the patients who reported awareness. Factors associated with accidental awareness during general anaesthesia were: high BMI (25-30 kg.m -2 ); low BMI (<18.5 kg.m -2 ); out-of-hours surgery; and use of ketamine or thiopental for induction. Standardised psychological impact scores at 30 days were significantly higher in awareness patients (median (IQR [range]) 15 (2.7-52.0 [2-56]) than in patients without awareness 3 (1-9 [0-64]), p = 0.010. Four patients had a provisional diagnosis of post-traumatic stress disorder. We conclude that direct postoperative questioning reveals high rates of accidental awareness during general anaesthesia for obstetric surgery, which has implications for anaesthetic practice, consent and follow-up.

Background and Aims:Early extubation is a desirable goal after general anesthesia. Very few studies have compared the effect of bispectral index (BIS) monitoring versus standard end-tidal anesthetic gas (ETAG) concentration monitoring on tracheal extubation time for halothane-based anesthesia. The aim of this study was to compare the effect of BIS versus ETAG-guided anesthesia on time to tracheal extubation for halothane-based anesthesia in general surgical setting.Methods:This was a randomized, controlled double-blind study. Sixty patients with the American Society of Anesthesiologists physical status Class 1 or 2, receiving halothane-based general anesthesia were randomized to BIS-guided (n = 30) and ETAG-guided anesthesia (n = 30). Time to tracheal extubation was measured. In BIS group, BIS value was kept between 40 and 60 while in ETAG group; ETAG value was kept between 0.7 and 1.3 minimum alveolar concentration. The two groups were compared using Student's t-test, and P < 0.05 was considered statistically significant. Data were processed and analyzed using SPSS version 17 software.Results:Mean time to tracheal extubation was significantly longer in BIS group (9.63 ± 3.02 min) as compared to ETAG group (5.29 ± 1.51 min), mean difference 4.34 min with 95% confidence interval (3.106, 5.982) (P < 0.05).Conclusion:In our study, the extubation time was significantly longer in BIS-guided anesthesia as compared to ETAG-guided anesthesia. ETAG monitoring promotes earlier extubation of patients as compared to BIS monitoring during halothane anesthesia.