The optimal effect-site concentration of remifentanil and propofol for keeping proper anesthesia and promoting early recovery during patient state index-guided anesthesia.

Backgroud: To determine the most suitable effect-site concentration of remifentanil and propofol for keeping proper anesthesia depth and early recover quickly under guidance of patient state index (PSI). Methodsː Elective gynecological laparoscopic surgery patients received concentration of propofol in high concentration (3 ug/mL, N = 25), middle concentration (2.5 ug/mL, N = 24), low concentration (2 ug/mL, N = 28) during maintenance. After finished intubation, propofol was adjusted to the target concentration by grouping, the concentration of remifentanil relied on the reaction of the formerly tested patient using 0.4 ng/mL as a step size began with 3.5ng/mL under PSI monitored. The primary measurements were the concentration of remifentanil, the change of intra-procedural data, and post-operation data including times to handle the change of the depth of anesthesia, blood pressure (BP) and heart rate (HR), extubation time, duration in PACU, hospital day, VAS score in the first day after sugery. Secondary measurements were density spectral array, intra-operative awareness, postoperative delirium. Results: The group of middle concentration required the minimum time for extubation and staying in PACU, kept steady process of anesthesia (P<0.05), the EC50 of remifentanil to suppression irritation from incision were 2.96 ng/mL (95% CI 2.75 to 3.14 ng/mL) in this group. Besides, low doses of remifentanil were more obvious than high doses in alpha wave of Density spectral array. Conclusions: With PSI guided anesthesia, the effect-site concentration of propofol was 2.5 ug/mL, keep stable anesthesia process and effective early postoperative recovery, meanwhile, EC50 of remifentanil was 2.96 ng/mL.