Preoxygenation enhances induction of anaesthesia with sevoflurane as assessed with BIS monitoring: A-492

Department of Anaesthesiology., Aretaieio Hospital, Medical School, University of%, Athens, Greece Background and Goal: Previous studies investigate methods enhancing the speed of inhalational induction of anaesthesia1. In a prospective randomized double-blind study we evaluated the speed of induction of anaesthesia with sevoflurane, with or without preoxygenation. Materials and Methods: Forty patients scheduled for hysteroscopy under general anaesthesia received for 10 min air or 100% O2 via a face-mask. Anaesthesia was induced with 7% sevoflurane in 100% O2 via a primed circle system. ZipprepTM electrodes were attached to the forehead of the patients for BIS monitoring. BIS values were recorded every 30 s, during the first 300 seconds of sevoflurane administration. Results: Demographics did not differ between groups. The group which inhaled O2 before induction exhibited significantly lower BIS values when compared to the group that received air (F 7.97, df 1, p 0.009). Means SD are shown in Figure 1.