Accuracy of auditory evoked potential index in monitoring depth of sevoflurane anesthesia in infants

Abstract

Objective To evaluate the accuracy of auditory evoked potential index （AAI） in monitoring the depth of sevoflurane anesthesia in infants. Methods Fifty ASA Ⅰ or Ⅱ pediatric patients, aged 1-3 yr, scheduled for elective surgery under general anesthesia, were enrolled in this study. Anesthesia was induced with propofol, cisatracurium and remifentanil. The patients were tracheal intubated and mechanically ventilated. PET CO2 was maintained at 35-45 mm Hg. Anesthesia was maintained with inhalation of sevoflurane. Fresh gas flow was first set at 6 L/min for 15 min and then reduced to 3 L/min. The end-tidal sevoflurane concentration （CETSeV） was maintained at 2.5% , 2.8% , 3.0% , 3.5% , 3.7% and 4.0% . Each C_ET SeV was maintained for 3 min. AAI was continuously monitored before induction of anesthesia, after induction, immediately before sevoflurane in- halation, and at the 6 CET Sev. Results AAI was negatively correlated with CET Sev （ r = - 0. 872, P 〈 0.01 ） . Conclusion AAI can accurately reflect the depth of sevoflurane anesthesia in infants. Key words: Evoked potentials, auditory ; Monitoring, intraoperative ; Child ; Anesthetics, inhalation