Background: We previously developed an automated total intravenous anesthesia control system that uses new closed-loop system algorithms to administer propofol, remifentanil, and rocuronium based on the bispectral index and train-of-four data. We recently improved this automated control system by adding a safety mechanism and using a modified monitoring device. Methods: Patients scheduled for elective surgery were randomly assigned to closed-loop feedback control (automatic group) or the manual administration of propofol, remifentanil, and rocuronium (manual group). The proportion of time during which the proper management of three-agent anesthesia was maintained during surgery was determined as the primary endpoint. Results: The proportion of time during which the three components of sedation, analgesia, and muscle relaxation were adequately controlled was 87.21 ± 12.79% in the automatic group, which was non-inferior to the proportion of 65.19 ± 20.16% in the manual group (p < 0.001). Adverse events during the operative or postoperative observation periods were significantly less frequent in the automatic group (54 patients, 90.0%) than in the manual group (60 patients, 100.0%; p = 0.027). Conclusion: Our three-agent automated control system, which features an improved muscle relaxation monitor and safety mechanism added to the basic control algorithms, maintained sedation, analgesia, and muscle relaxation appropriately in a manner non-inferior to anesthesiologists without compromising safety.

Purpose: In this study, we aimed to develop and evaluate an automated phenylephrine delivery system by lower limit control for the management of intraoperative hypotension, assessing its efficacy in maintaining adequate blood pressure levels. Methods: Twenty patients undergoing surgery with anticipated blood pressure fluctuations were enrolled in this study. Patients were randomly assigned to two groups. Noninvasive blood pressure (NIBP) was measured at 2.5-min intervals using an upper arm cuff. In the automated group, phenylephrine administration was governed by an automated system that delivered bolus doses and adjusted the continuous infusion rate when mean blood pressure (MBP) dropped below 65 mmHg. In the manual group, phenylephrine administration was initiated by the attending anesthesiologist under the same MBP threshold. Propofol, remifentanil, and rocuronium were administered via the automated delivery system for total intravenous anesthesia, to minimize hemodynamic variability between groups. The primary end point was the percentage of time during which MBP remained above 65 mmHg and systolic blood pressure below 140 mmHg, measured from the initiation to the cessation of intravenous anesthesia and assessed using a non-inferiority test. Results: The automated group adequately maintained blood pressure within the target range for 84.53% of the time, compared to 72.45% in the manual group, confirming statistical non-inferiority (p < 0.001). Conclusion: This system effectively managed intraoperative hypotension using intermittent NIBP measurements, which are more feasible in clinical practice. Despite relying on less frequent and lower-resolution blood pressure data, it demonstrated efficacy comparable to anesthesiologist-led management, indicating its potential for broader clinical application.

Background/Objectives: No study has simulated rocuronium (Rb) effect-site concentrations (Ce_Rb) using real-time data—such as Rb concentrations, train-of-four (TOF) count (TOFC), and TOF ratio (TOFR)—under mechanical Rb administration. Therefore, we aimed to investigate post-operative recurarization and changes in the Ce_Rb after sugammadex (SGX) administration under conditions where Rb dosing was strictly administered using an automated delivery system for total intravenous anesthesia. Methods: This non-interventional, retrospective, observational study included 74 patients from an existing clinical trial who met the study criteria. Rb was automatically administered during surgery to maintain a TOFC of 1. SGX (2 mg/kg) was manually administered post-surgery, and the time until the TOFR reached ≥0.9 (if the time exceeded 3 min, 0.5 mg/kg SGX was added every minute). The results were analyzed using a pharmacokinetic (PK)–pharmacodynamic (PD) simulation model of the Rb-SGX complex. Results: The average total dose of administered SGX was 2.2 ± 0.4 mg/kg (mean ± standard deviation). The time from SGX administration till the TOFR reached ≥0.9 was 2.9 ± 1.1 min. Furthermore, Ce_Rb at recovery (Ce_r) was 0.3 ± 0.2 μg/mL. Notably, no cases showed post-operative recurarization within 24 h of surgery. PK–PD model simulations revealed that Ce_Rb increased again after reaching the lowest Ce_Rb in 72 cases, although no increase was recorded beyond Ce_r, suggesting no numerical risk of recurarization. Conclusions: Our results show that if TOFC of 1 is strictly maintained intraoperatively and SGX is administered till the TOFR reaches ≥0.9, post-operative recurarization does not occur.

Background/Objectives: The aim of this study was to develop evaluation metrics for lower-limit vasopressor control, a strategy intended to prevent prolonged intraoperative hypotension under noninvasive blood pressure monitoring. Methods: Using general-purpose simulation software, we developed a blood pressure generation model with one-minute intervals and an automated vasopressor administration model with five-minute intervals. The latter delivered drugs according to predefined rules when systolic blood pressure (sBP) fell below a threshold. Four dosing strategies were constructed by combining bolus, repeated low-dose bolus, and continuous infusion approaches. Simulations were performed, and the following evaluation metrics were calculated: (1) proportion of time below threshold (PTBT), (2) mean value below threshold (MVBT), (3) average sBP, and (4) median performance error (MDPE) and median absolute performance error (MDAPE). Results: PTBT and MVBT analyses showed that incorporating continuous infusion reduced both the duration and severity of hypotension. Moreover, adding MVBT to the average sBP after subtracting the threshold quantified the extent to which sBP exceeded the threshold on average. In contrast, MDPE and MDAPE varied substantially with the assumed target pressure, highlighting their limitations in evaluating lower-limit control without a fixed target. Conclusions: For lower-limit control, metrics such as PTBT, MVBT, and average sBP offer useful insights into control stability and hypotension avoidance, whereas MDPE and MDAPE may be unsuitable for quantitative assessment when the primary goal is to exceed a threshold rather than achieve a fixed target pressure.