A Clinical Comparation Between Sevoflurane And Enflurane Anesthesia With A Closed-Loop Anesthesia System

Object: A closed-loop anesthesia system was built using BIS as the controlvariable, a proportional-integral-differential incorporated with adaptive control algorithm, and a target-controlled infusion system as the control actuator. And this system was used for anesthesia in 16 selective abdomen operations. Closed-loop performance was assessed with is sevoflurane and compare with another closed-loop anesthesia system -- "Closed-loop control of anesthesia with enflurane: a clinical investigations" in the stability of anesthetic depth's control and hemodynamic control, the variation of HRV, the quantity of sevoflurane and the state of palinesthesia.Methods: Sixteen adult patients, scheduled for the selective abdomen operation, General anesthesia was induce using intravenous injection of propofol (1.5-2mg/kg), fentanyl (4ug/kg), pipecuronium (0.08-0.1mg/kg). The control group, the all process of induction and maintenance was controlled by the closed-loop target-controlled infusion system. Anesthesia processes were controlled with sevoflurane to an intra-operative target, bispectral index of 55 in all cases. Adequacy of anesthesia and change of hemodynamic and the concentration of sevoflurane during closed-loop control were assessed clinically and by calculating the median performance error, the median absolute performance error, and the mean offset of the control variable.Results: ①The median performance error (0.59, 1.6), the median absoluteperformance error (6.35, 6.39) ,the mean wobble (6.33, 5.91) and the mean offset of the BIS from the set point(0.15, 0.91 )were not statistically difference(p>0.05). (2) When the operations began, HRV in both systems was statistically difference (p<0.05). However, compared with their own basic HRV, enflurane's system was statistically difference(p<0.05) and sevoflurane 's system was not (p>0.05). ③The changes of HR were similar in two systems and was not statistically difference(p>0.05),but the state of BP was better in sevoflurane' s system than in enflurane' s system(p<0.05) compared before operation began with after operation began. ④ The state of palinesthesia of the patients was better in sevoflurane' s system than in enflurane' s system(p<0.05). ⑤None of the patients in two systems know the things in operations when we asked them about operations after operations.Conclusions: ①BIS can be used for an electroencephalogram-derived measure of anesthetic depth. BIS in two systems can be controlled closed the target BIS and was stable. ②HVR in sevoflurane' s system was controlled better than in enflurane' s system. ③The hemodynamic controls were not statistically difference in two systems and both of them were stable, but sevoflurane' s system is better than enflurane' s system compared before operation began with after operation began. ④The state of palinesthesia of the patients was better in sevoflurane' s system than in enflurane' s system. ⑤None of the patients in two systems know the things in operations when we asked them about operations after operations.