Performance of bispectral index during epidural anesthesia and combined with propofol

Objective To evaluate the sedative effect of epidural anesthesia and interaction between epidural anesthesia and propofol using bispectral index( BIS). Methods Fourty patients were randomly allocated to 2groups receiving either 5 mL of 1% lidocaine through the epidural catheter( group L) or 5 mL of epidural normal saline(group S) with 20 patients in each. 8 minutes later,after confirmation of epidural administration,group L received 5 ~ 10 mL of combination of 1% lidocaine and 0. 5% ropivacaine,whereas group S received 8 mL of epidural normal saline. BIS,MAP,HR and SpO2were recorded before and 8,15 and 30 min after first epidural injection. 30 min after first epidural injection,general anesthesia was induced with propofol via target-controlled infusion pump,the initial plasma concentration was 4 μg / mL. The effect site concentration of propofol when BIS firstly achieved 50 was recorded by another anesthesiologist. Remifentanil and rocuronium were administrated to accomplish the endotracheal intubation. Results There was no significant change in BIS after epidural infusion in both groups,and no significant difference exist between groups at all time points regarding BIS. The effect site concentration of propofol on BIS 50 in group L was significantly less than group S( P 0. 05). Conclusions Epidural anesthesia alone doesn't exert sedative effect measured by BIS. However,when combined with propofol,epidural anesthesia can potentiate the sedative effect of propofol.