Relieving the pressure: the effect of active carbon dioxide aspiration on postoperative pain after laparoscopic cholecystectomy

Abstract

Background: Residual carbon dioxide (CO₂) after laparoscopic cholecystectomy (LC) may contribute to early postoperative pain. Active aspiration of CO₂ has been proposed as a simple adjunct, but large cohort data remain limited. Methods: This non-randomized prospective cohort study included 270 patients undergoing LC between May 2025 and October 2025. Patients were allocated to either the active aspiration group (n = 135) or the passive evacuation group (n = 135). Pain was evaluated using the Visual Analog Scale (VAS) at 4 and 24 h. Statistical analyses included chi-square tests, independent and paired t-tests, and Pearson correlation. A priori power analysis determined that 266 patients (133 per group) were required (effect size d = 0.40, α = 0.05, power = 0.90). Results: The aspiration group had significantly lower pain scores at both 4 h (3.48 ± 1.08 vs. 5.30 ± 1.60; p < 0.001) and 24 h (1.69 ± 0.94 vs. 3.59 ± 1.38; p < 0.001). Active aspiration was associated with lower pain scores at both time points (p < 0.001). Conclusion: Active evacuation of residual CO₂ was associated with lower postoperative pain scores following LC. Given the non-randomized design, causal inference is limited, and the findings should be interpreted cautiously.