Closed-loop target-controlled infusion system for propofol guided by bispectral index applied in patients undergoing shoulder arthroscopy in the beach chair position- a randomized controlled trial

Background To compare the efficacy of anesthetic depth control using closed-loop and open-loop target controlled infusion (TCI) system of propofol guided by BIS in patients undergoing shoulder arthroscopy in the beach chair position (BCP). Methods 120 patients underwent shoulder arthroscopy surgery in the BCP were randomized into two groups, the open-loop (O) group and the closed-loop (C) group. During the maintenance phase, BIS value was used as the feedback variable for TCI system of propofol in both groups. The Global score (GS) and the percentage of adequate anesthesia, the frequency of propofol regulation, and consumption of propofol were calculated. The MMSE scores of the day before and 1 day after surgery, serum GFAP and S100B proteins before anesthesia, after extubation and 1 day after surgery were compared. Results The GS and the proportion of appropriate anesthesia time were better in the group C. The percentage of overshoot time was lower in the group C. The frequency of propofol regulation was observed higher in the group C. Propofol consumption in the group C was significantly lower than that in the group O. The MMSE scores, the GFAP and S100B protein concentrations had no significant difference between the two groups. Conclusion Propofol administration using close-loop TCI system guided by BIS may increase the percentage of adequate anesthesia and shorten the percentage of overshoot time compared with open-loop TCI model in anesthesia maintenance phase in patients undergoing shoulder arthroscopy in the BCP, and do not increase the risk of POCD.