Exploration Of Optimal Effect-site Concentration Of Propofol Combined With Remifentanil For Patients Undergoing Gynecological Laparoscopic Surgery With PSI Monitoring

Objective The purpose of this research is to assess effect of combined infusion with remifentanil and propofol at different effective concentration on general anesthesia and the quality of recovery in gynecological laparoscopic surgery patients with monitored by the Patient State Index（PSI）.Additionally,to determine the optimal effect-site concentration of propofol and remifentanil.Methods Patients aged 30 to 64 years old with BMI 18.5 to 29.5 kg/m²,ASA status wasⅠ-Ⅱ,and scheduled for gynecological laparoscopic surgery from May 2021 to April 2022were selected.The study was divided into two parts.In part 1,the 95%effective effect-site concentration（EC95）of remifentanil when propofol was infused at effect-site concentrations of 3μg/ml（Ph group）,2.5μg/ml（Pm group）,2μg/ml（Pl group）was calculated by the sequential method and probit method,respectively.In part 2,patients were recruited and randomly divided into three groups according to different effect-site concentration of remifentanil and propofol:2.8+3μg/ml（Rl+Ph group）,3.3+2.5μg/ml（Rm+Pm group）and 5.8+2μg/ml（Rh+Pl group）.In part 1,the change of PSI before and after skin incision were recorded.In part 2,HR and MAP were continuously measured and recorded at different points:after intubation（T₀）,skin incision（T₁）,drug discontinuance（T₂）,and awakening（T₃）.Besides,recorded operation time and total dose of propofol.The awakening time,extudation time,and PACU duration were also recorded.Evaluate the VAS scores at 15 min,30 min,1 h and 24 h after operation.The numbers of manual intervention and rescue analgesia within 24 h after operation,and the incidence of intraoperative awareness,postoperative agitation,nausea and vomiting were also recorded.Results 193 patients were included in the two parts of the study.In the part 1,the median effective effect-site concentration（EC50）and 95%confidence interval（95%CI）of remifentanil in the three groups were 1.8（0.936～2.267）,2.4（2.746～3.144）and 5.1（4.863～5.469）ng/ml,respectively.The EC95 and 95%CI were 2.8（2.334～7.325）,3.3（3.141～4.158）and 5.8（5.443～7.404）ng/ml,respectively.In part 2,no significant variance in change of MAP was observed among the three groups at the same time（P>0.05）.Compared with group Rl+Ph and Rm+Pm,HR in group Rh+Pl at T₁and T₂were significantly reduced,and there was statistically significant difference among the three groups（P<0.05）.The MAP and HR of the three groups at T₃were significantly higher than those at T₀～T₂（P<0.05）.Compared with the group Rl+Ph and Rm+Pm,group Rh+Pl showed a noteworthy decrease in the total dose of propofol and a remarkable reduction in the awakening time,extubation time and PACU duration（P<0.05）.There is no significant difference in VAS score among the three groups at 15min,30 min,1 h and 24 h after operation（P>0.05）.No application of rescue analgesics for the three groups.No significant difference was observed in pressing the analgesic pump and the incidence of nausea and vomiting among the three groups（P>0.05）.No adverse complications such as intraoperative awareness and postoperative agitation were occurred.Conclusion Under the guidance of PSI,the combined infusion of remifentanil and propofol with effect-site concentration of 5.8 ng/ml and 2μg/ml can maintain anesthesia stably,which is conducive to promote postoperative recovery,early extubation,and short PACU duration.