OBJECTIVETo compare the effects of epidural anesthesia with 1.5% lidocaine and 0.5% ropivacaine on propofol requirements, the time to loss of consciousness (LOC), effect-site propofol concentrations, and the hemodynamic variables during induction of general anesthesia guided by bispectral index (BIS) were studied.

METHODSForty-five patients were divided into three groups to receive epidurally administered saline (Group S), 1.5% (w/w) lidocaine (Group L), or 0.5% (w/w) ropivacaine (Group R). Propofol infusion was started to produce blood concentration of 4 mug/ml. Once the BIS value reached 40~50, endotracheal intubation was facilitated by 0.1 mg/kg vecuronium. Measurements included the time to LOC, effect-site propofol concentrations, total propofol dose, mean arterial blood pressure (MABP), and heart rate (HR) at different study time points.

RESULTSDuring induction of anesthesia, both Groups L and R were similar for the time to LOC, effect-site propofol concentrations, total propofol dose, MABP, HR, and BIS. The total doses of propofol administered until 1 min post-intubation were significantly less in patients of Groups R and L compared with Group S. MABP and HR were significantly lower following propofol induction compared with baseline values in the three groups, or MABP was significantly increased following intubation as compared with that prior to intubation in Group S but not in Groups R and L while HR was significantly increased following intubation in the three groups.

CONCLUSIONEpidural anesthesia with 1.5% lidocaine and 0.5% ropivacaine has similar effects on the time to LOC, effect-site propofol concentrations, total propofol dose, and the hemodynamic variables during induction of general anesthesia.