Accuracy of BIS value for monitoring depth of sevoflurane-nitrous oxide anesthesia in children / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the accuracy of BIS value for monitoring the depth of sevoflurane-nitrous oxide in children. Methods Seventy-two ASA Ⅰ or Ⅱ children aged 1-14 yr undergoing abdominal surgery were randomly assigned into 3 groups ( n = 24 each)sevoflurane group (group S), sevoflurane + 30% N2O group (group SN1 )and sevoflurane + 60% N2O (group SN2 ). Anesthesia was induced with atropine, lidocaine, propofol, rocuronium and remifentanil. After tracheal intubation, the patients were mechanically ventilated. PETCO2 was maintained at 35-45 mm Hg. Anesthesia was maintained with 2.5% sevoflurane combined with 0, 30% and 60% nitrous oxide in group S, SN1 and SN2 respectively. The end-tidal sevoflurane concentration (CETSev) was maintained at 2.5%, 2.0% and 1.5%. Each CETSev was maintained for at least 10 min after the begining of the surgery. Then the CETSev was modified to maintain BIS value at 40-60. BIS value was recorded before anesthesia induction and each stable CETSev. CETSev was recorded at maintaining BIS value of 40-60 for at least 20 min ( C50 ).Results BIS value and C50 were significantly lower in group SN2 than in group S and SN1 ( P ＜ 0.05), while no significant difference was found between group S and SN1 ( P ＞ 0.05). BIS value was negatively correlated with CETSev in all 3 groups (r = -0.736, -0.817, -0.729, P ＜ 0.01).There was no significant difference in the correlation coefficients among the 3 groups ( P ＞ 0.05 ). Conclusion BIS value can accurately reflect the depth of sevoflurane-nitrous oxide anesthesia in children.