Fig 1.
Of the 180 included patients, 1 and 3 patients were excluded from the closed-loop and opened-loop group, respectively, due to artifact of BIS, too short maintenance duration, or operation error. Thus, 89 and 86 patients were available for analysis in the two groups, respectively.
Table 1.
Medical and demographic characteristics of patients in the closed-loop group and the opened-loop group.
Table 2.
Comparison of anesthetic procedures between the two groups during the induction phase.
Table 3.
Comparison of anesthetic procedures between the two groups during the maintenance phase.
Fig 2.
Comparison of the Global score (GS) between the two groups.
Global score (GS) could reflect the overall performances of the closed-loop infusion system, including the fluctuation of BIS, the proportion of time of adequate anesthesia (BIS between 40 and 60), median absolute performance error (MDAPE), and Wobble. The mean GS were 22.21±8.50 and 27.19±15.26 in the closed-loop and opened-loop groups during the maintenance phase, respectively (p = 0.009).
Fig 3.
Comparison of the percentage of time that BIS was between 40 and 60 between two groups.
The mean proportion of time that BIS was between 40 and 60 were 84.11±9.50% and 79.92±13.17% in the closed-loop group and opened-loop group, respectively (p = 0.016).
Fig 4.
Two samples of the result of the trends of BIS and calculated target concentrations of propofol during anesthesia from the two groups.
Two samples of the result of the trends of BIS (red lines) and calculated target concentrations of propofol (green lines) during the induction phase and maintenance phase in the two groups. The above was the closed-loop group (GS = 15.98) and the below was opened-loop group (GS = 30.11).
Table 4.
Effectiveness of the closed-loop control system.