Effects of different target effect-site concentrations of sufentanil on MACBAR of desflurane in patients undergoing abdominal surgery

Abstract

Objective To evaluate the effects of different target effect-site concentrations (Ces) of sufentanil on the minimum alveolar concentration of desflurane inhibiting stress responses to skin incision (MACsAR) in 50％ of patients undergoing abdominal surgery.Methods Eighty-three patients,aged 20-60 yr,scheduled for elective abdominal surgery with an expected incision longer than 10 cm,were enrolled in the study.All the patients were randomly allocated to one of three groups using a random number table:control group (group C,n =28),sufentanil with target Ce of 0.1 ng/ml group (group S1,n =27),and sufentanil with target Ce of 0.3 ng/ml group (group S2,n =28).After tracheal intubation,desflurane inhalation was started,and sufentanil was infused at the preset target Ces in S1 and S2 groups.The initial end-tidal concentration of desflurane was 9.0％ in group C,and 6.0％ in S1 and S2 groups.The target concentration was maintained at least for 15 min.The modified up-and-down method was used to perform the test.The end-tidal concentration of desflurane was adjusted in the next patients according to the response to skin incision.The MACBAR and 95％ confidence interval of desflurane was calculated according to the up-and-down method.Mean arterial pressure and heart rate were monitored and recorded and rate-pressure product was calculated.Results The MACBAR (95％ confidence interval) ofdesflurane was 11.2％ (11.1％-11.3％),7.8％ (7.7％-7.9％),and 4.2％ (4.1％-4.3％) in C,S1 and S2 groups,respectively.MACBAR and rate-pressure product of desflurane were significantly lower in S1 and S2 groups than in C group,and in S2 group than in S1 group (P ＜ 0.05 or 0.01).Conclusion The optimum target Ce of sufentanil is 0.3 ng/ml when combined with desflurane in the patients undergoing abdominal surgery. Key words: Anesthetics, inhalation ; Sufentanil; Dose-response relationship, drug; Stress