Application of bispectral index to titrating Sevoflurane anesthesia in intracranial operations

Objective To investigate the effect of BIS monitoring during Sevoflurane anesthesia in patients undergoing elective intracal surgery.Methods Forty ASA Ⅰ～Ⅱ patients undergoing elective intracal surgery were randomized to one of two groups(n= 20,each):BIS group and control group.In BIS group Sevoflurane was titrated to keep BIS values between 50~60 during operation,but in control group the anesthesiologist was blinded to the BIS score.The BIS value was increase to 60～70 at 20 min before the end of operation.In control group the depth of anesthesia was maintained based on the clinical experience of the anesthesiologist.The BIS values and the end-tidal Sevflurane MAC(MACET) before and during anesthesia and at extubation,emergence time,extubation time and orientation resume time were recorded and compared between the two groups.Results The average BIS values were higher and end-tidal Sevoflurane concentration was lower in BIS group than in control group.The time from the end of surgery to eye opening,to exbuation and orientation resume were significantly shorter in BIS group than in control group.Conclusion Titration of Sevoflurane using BIS monitoring can be used in patients undergoing elective intracal surgery,and also contribute to faster recovery from anesthesia.