Clinical study of propofol sedation by feedback target controlled infusion during epidural block

Objective To study the feasibility of sedation with propofol by feedback target controlled infusion(FTCI) during epidural block. Methods Fifty patients with epidural block were randomly divided into two groups:FTCI group and target controlled infusion(TCI) group(n=25 in every group). For all patients in two groups, the target concentration of propofol was set at 1.0μg/kg at the beginning. When concentration of propofol reached the equilibrium point for 3 minutes that was increased to 1.8μg/ml. The value was kept throughout anesthesia for patients in TCI group. In FTCI group, sedation was controlled by FTCI according to changes of bispectral index(BIS). If BIS was more than 75 TCI was activated. In two groups parameters BIS, MAP, HR, SPO2 and OAA/S grades were respectively recorded before anesthesia(T1),before FTCI(T2),cutting skin(T3), exploration(T4),for 60 minutes after operation(T5),the end of operation(T6) and regain consciousness(T7). The differences between the maximum and the minimum of OAA/S, BIS and MAP grades were calculated respectively(They are named as △OAA/S,△BIS and △MAP correspondingly). Results In two groups, BIS,MAP and HR at T2 were lower than those at T1(P0.05). MAP and HR at T4 were higher than those at T1(P0.05). At T4 BIS,MAP and HR in TCI group were obviously increased than those in FTCI group. But at T6 the above values in TCI group were significantly decreased than those in FTCI group (P0.05).During operation △OAA/S? △BIS and △MAP were also increased obviously(P0.05). The total dose of propofol(410±33mg)in FTCI group were obviously lower than that(528±59mg) in TCI group, There was significant difference between the two groups(P0.01). Conclusions By BIS used as a feedback variable of FTCI, better sedation can be achieved in epidural anesthesia with propofol. Depth of sedation can be accurately controlled and evaluated during operation. This method has the advantages of less propofol, rapid emergence and more stable blood pressure.