No effect of cardiopulmonary bypass on hypnosis in patients anaesthetized with propofol and alfentanil

Abstract

Background. The effect of cardiopulmonary bypass (CPB) on the level of anaesthetic depth has not been studied previously in a randomized way. Methods. We assessed the effect of CPB on the propofol needed to maintain a fixed bispectral index score, and on the recovery from anaesthesia in 22 patients undergoing coronary artery bypass graft surgery with CPB (on-pump) compared with 18 patients operated on without CPB (off-pump). Anaesthesia was induced and maintained with propofol and alfentanil. Throughout the procedure, the infusion rate of propofol was adjusted to keep the BIS value at 40 ± 5. Results. With the off-pump technique, the duration of surgery and anaesthetic administration were significantly greater. The need for propofol in proportion to time was exactly the same in both groups. During anaesthesia and the first 3 h thereafter, the BIS recordings were similar in both groups. No differences were detected in the time to awakening or tracheal extubation. Conclusions. CPB does not affect propofol requirements or immediate postoperative recovery compared with the off-pump technique.