The Development of an Automated Fluid Infusion Management System to Prevent Hypotension During General Anesthesia: A Randomized Clinical Trial

Background/Objectives: This study aimed to develop and evaluate an automated fluid infusion management system for preventing hypotension during general anesthesia. Methods: This study was a single-blind, randomized, non-inferiority, clinical trial. Seventy-nine patients undergoing surgery under general anesthesia were randomly assigned to either an automatic group or a manual group. In the automatic group, the infusion rate was automatically adjusted based on stroke volume (SV) and effective arterial elastance (Ea), whereas in the manual group, the attending anesthesiologist manually adjusted the infusion rate according to the Enhanced Recovery After Surgery (ERAS) protocol. The primary endpoint was the proportion of time during anesthesia that mean arterial pressure (Pm) was maintained at ≥65 mmHg. Secondary endpoints included the proportion of time the estimated stroke volume index (esSVI) was below the threshold, total fluid volume administered, total phenylephrine dose, urine output, blood loss, and average estimated stroke volume variation (esSVV). Results: The results demonstrated non-inferiority of the automatic group to the manual group in maintaining Pm ≥ 65 mmHg (automatic group: 82.0 ± 12.7%, manual group: 79.9 ± 15.7%; difference [automatic group−manual group]: 2.0 percentage points; one-sided 97.5% CI lower limit: −4.7%; non-inferiority margin: −5%). There were no significant differences between the groups in total fluid volume, phenylephrine dose, urine output, or blood loss. No severe adverse events or device-related adverse events were observed. Conclusions: The automated system maintained intraoperative blood pressure safely and effectively.