Efficacy of bispectral index in guiding sevoflurane anesthesia in children

Objective To evaluate the efficacy of bispectral index (BIS) in guiding sevoflurane anesthesia in children. Methods Forty-eight ASA Ⅰ or Ⅱ pediatric patients aged 1-12 yr undergoing elective urological surgery were randomized into 2 groups ( n = 24 each) : group Ⅰ control and group Ⅱ BITS. Each group was further divided into 3 subgroups according to the age (n = 8 each) : subgroup A ( 1 yr≤age < 3 yr) ,subgroup B (3 yr≤ age<6 yr ) and subgroup C (6 yr≤age ≤ 12 yr). The patients were premedicated with IM atropine 0.015-0.02 mg/kg. Anesthesia was induced with 5% sevoflurane and 60% N2O in O2. Tracheal intubation was facilitated with vecuronium 0.1 mg/kg. Anesthesia was maintained with inhalation of sevoflurane and,50% N2O in O2 and intermittent Ⅳ bolnses of vecuronium and fentanyl. In BIS group, BIS was maintained at 40-60 during operation and at 60-75 during the 15 min before the end of surgery. BIS was monitored and recorded but not available to the anesthesiologist in control group and the depth of anesthesia was maintained based on hemodynamic changes and clinical signs. MAP, HR, end-tidal sevoflurane concentration, BIS, emergence time, extubation time and PACU discharge time were recorded. The amount of sevoflurane consumed was calculated. Results There was no significant difference in the demographic data between the cotresponding age groups of BIS and control group. The BIS were maintained at 40-60 in control group. The BIS was significantly higher in BIS group than in control group except the subgroup A. The end-tidal sevoflurane concentration was significantly lower, and the emergence time, extubation time and PACU discharge time were significantly shorter in BIS group than in control group. There was no significant difference in MAP and HR between the 2 groups. Conclusion BIS monitoring can reduce sevoflurane consumption and allow faster emergence from sevoflurane anesthesia in children over 1 yr of age. Key words: Anesthetics,inhalation;  Electroencephalography;  Child