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.

Chemotherapy-induced peripheral neuropathy (CIPN) is one of the most difficult-to-alleviate side effects of chemotherapy, impacting the patient’s daily activities and quality of life and frequently necessitating the discontinuation or dose reduction of anticancer drugs. An effective treatment for CIPN is yet to be established. Herein, we report the case of a patient who developed CIPN after receiving paclitaxel as postoperative chemotherapy for breast cancer. The patient experienced difficulties in performing daily activities owing to pain in her fingers and toes despite attempts to treat these symptoms with medications. Stellate and lumbar sympathetic ganglion blocks improved CIPN-induced symptoms of numbness and pain in the extremities. Thereafter, lumbar sympathetic ganglion block was performed once every 6 months, markedly improving the patient’s quality of life. Accordingly, sympathetic nerve block can facilitate pain control in patients with CIPN refractory to pharmacotherapy.

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.