Combined anesthesia with isoflurane and different doses of remifentanil: A study of pharmacodynamics / 中国微创外科杂志

ABSTRACT

Objective To study pharmacodynamic changes of combined anesthesia with remifentanil at different target plasma concentrations and isoflurane at different minimal alveolar concentrations(MAC) in laparoscopic operations. Methods Forty-five patients with ASA status Ⅰ~Ⅱ,receiving selective laparoscopic cholecystectomy or laparoscopic oophorocystectomy,were included.The patients were randomly divided into three groups with 15 patients in each group.In the Group A,anesthesia was maintained with isoflurane inhalation at the MAC of 1.3;in the Group B,anesthesia was maintained with both isoflurane inhalation at the MAC of 0.6 and remifentanil target-controlled infusion at 4 ng/L;and in the Group C,anesthesia was maintained with both isoflurane inhalation at the MAC of 0.4 and remifentanil target-controlled infusion at 6 ng/L.Pharmacodynamic parameters and recovery characteristics,including bispectral index(BIS),heart rate variability(HRV),mean arterial pressure(MAP),heart rate(HR),time to additional administration of muscle relaxants,time to the recovery of spontaneous breathing,time to eye opening,time to endotracheal extubation,time to the recovery of orientation,and follow-up survey of "awareness during operation",were compared among the 3 groups.Results ①The BIS value was lower in the Group A than in the Group B and C at the time of pneumoperitoneum for 2 min and removal of the gallbladder or the ovarian cyst.The measures of HRV were higher in the Group A than in the Group B and C at the time of pneumoperitoneum for 2 min and removal of the gallbladder or the ovarian cyst.The measures of MAP and HR in the Group A were higher than those in the Group C at the time of pneumoperitoneum for 2 min,and were lower than those in the Group C at the time of the endotracheal extubation and the recovery of consciousness.②Either isoflurane inhalation at the MAC of 0.6 combined with remifentanil target-controlled infusion at 4 ng/L or isoflurane inhalation at the MAC of 0.4 combined with remifentanil target-controlled infusion at 6 ng/L provided satisfactory anesthetic maintenance.③Significantly shorter time to endotracheal extubation,to eye opening,and to the recovery of orientation were recorded in the Group B and C than in the Group A.Conclusions Anesthesia with target-controlled infusion of remifentanil combined with inhalation of isoflurane can be used for laparoscopic surgery.Pharmarcodynamic parameters and recovery characteristics show that combined use of remifentanil infusion at 4 ng/L and isoflurane inhalation at the MAC of 0.6 provides optimal anesthetic maintenance.