Optimal Programmed Intermittent Epidural Bolus Interval for Video-Assisted Thoracic Surgery Lobectomy: A Biased-Coin Up-Down Study of Ropivacaine-Sufentanil

Programmed intermittent epidural bolus (PIEB) is a novel epidural anesthesia technique for video-assisted thoracic surgery (VATS). However, the optimal setting of the PIEB parameters remains to be determined. This study aimed to determine the optimal time interval for the PIEB regimen of 10 mL ropivacaine 0.15% with sufentanil 0.4 μg/mL within 24 hours of VATS lobectomy. We conducted a double-blind, sequential allocation trial with a biased-coin up-down design. 42 patients scheduled for VATS lobectomy were enrolled in the study. All participants received a fixed programmed bolus dose of 10 mL of 0.15% ropivacaine combined with 0.4 μg/mL sufentanil. The PIEB interval was initially set at 180 minutes for the first patient and adjusted for subsequent patients according to the biased-coin design, with intervals of 180, 150, 120, and 90 minutes (corresponding to groups 180, 150, 120, and 90, respectively). The primary outcome was the achievement of effective analgesia, defined as the absence of any requirement for patient-controlled epidural analgesia (PCEA) or additional rescue analgesic interventions within 24 hours after the loading dose. Secondary outcomes included the documentation of postoperative adverse effects, such as nausea, vomiting, hypotension, pruritus, and dizziness. A total of 40 patients were included in the study. Using Isotonic Regression analysis, the estimated effective interval for 90% (EI90) of patients was determined to be 97.4 minutes (95% confidence interval [CI]: 91.6-103.1 minutes). The incidence of postoperative hypotension varied significantly across groups, with the highest probability observed in group 90 (64.3%), followed by group 120 (18.8%) and group 150 (11.1%). The estimated effective interval for the EI90 between PIEB of 10 mL of ropivacaine 0.15% with sufentanil 0.4 μg/mL was approximately 100 minutes. Chinese Clinical Trial Registry, ChiCTR2300077174.