Effect Of Epidural Ropivacaine Block On Sedation And Hypnosis Of Propofol Target-controlled Infusion

Objective To evaluate the effect of epidural ropivacaine block on sedation and hypnosis of propofol target-controlled infusion. Methods Fifty ASA I -II patients scheduled for upper abdominal surgery were randomly assigned into three groups: ropivacaine group, (group GR, n=15), lidocaine group, (group GL, n=15) and placebo(control) group, (group GC, n=20). There was no any premedication in three groups. Epidural catheter was inserted through the needle placed at T9-io and advanced cephalad for 3cm.Fifteen minutes after epidural local anesthetics or saline administration, a propofol target-controlled infusion(Ct=4 ug · ml-1) was started until one minute after tracheal intubation. The consumed time of patients losing consciousness, the target concentration and the consumed amount of propofol, BIS, MAP and HR were all recorded in fixed time.Results The consumed time of losing consciousness, the target concentration and the consumed amount of propofol in three groups were(111±17)second, (112±14) second, (134 ± 22) second; (1. 44±0.16) ug ml-1, (1.48 ± 0. 16) ug . ml-1, (1.66±0. 22) ug · ml-1; (1. 26 ± 0. 10)mg · ml-1,(1.23±0. 16) mg . kg-1 , (1.41±0. 19) mg · kg-1, respectively. There werestatistically significant difference between the two experimental groups and control group, and no statistically significant difference between ropivacaine group and lidocaine group.Conclusions Epidural ropivacaine block can enhance the sedative and hypnotic effect of propofol target-controlled infusion. The propofoi sparing effect is most likely caused by decreasing threshold of central sedation and hypnosis when epidural ropivacaine administration.