Optimising pneumoperitoneum pressure to minimise post-operative shoulder tip pain: A randomised controlled trial of 10 versus 14 mmHg CO2 in laparoscopic cholecystectomy

Background: Post-operative shoulder tip pain (STP) is an established side effect of laparoscopic cholecystectomy, primarily attributed to diaphragmatic irritation from residual carbon dioxide (CO 2 ) insufflation during surgery. The purpose of this trial was to evaluate the severity of STP and the day of discharge after surgery between patients undergoing laparoscopic cholecystectomy who had low-pressure (10 mmHg, CO 2 ) and standard-pressure (14 mmHg, CO 2 ) pneumoperitoneum. Patients and Methods: In this single-centre, double-blind, randomised controlled experiment, 100 patients scheduled for laparoscopic cholecystectomy were randomly allocated to one of two groups of 50 patients each, receiving either standard-pressure or low-pressure pneumoperitoneum. The primary outcomes included post-operative STP scores measured using a validated 10-point numerical rating scale at 3, 6, 12, 24, 48 and 72 h postoperatively. The secondary outcome was duration of hospitalisation. P < 0.05 was considered statistically significant. Results: Study participants comprised 69% of females with a mean age of 44.2 ± 12.8 years. Despite observed demographic variations, there were no statistically significant differences in baseline characteristics between the groups ( P > 0.05 for all comparisons). The standard-pressure group had significantly higher mean pain scores than the low-pressure group at 3 h (2.3 ± 2.4 vs. 0.9 ± 1.3), 6 h (1.5 ± 1.8 vs. 0.5 ± 0.9), 12 h (1.0 ± 1.4 vs. 0.4 ± 0.8) and 24 h (0.4 ± 0.8 vs. 0.1 ± 0.5) after surgery, with P = 0.006, 0.007, 0.018 and 0.049, respectively. From the 2 nd day onwards, pain scores became minimal and showed no significant difference between the groups ( P = 0.662). The mean hospital stay was 2.04 ± 0.198 days versus 2.00 ± 0.000 days ( P = 0.159), with no clinically meaningful difference. Conclusion: This study provides Level 1 evidence that low-pressure pneumoperitoneum during laparoscopic cholecystectomy significantly reduces STP for the first 24 h postoperatively, though this effect does not persist beyond 48 h. Hospital length of stay remained equivalent between the groups, suggesting that early pain reduction alone does not translate to accelerated discharge. This suggests the need for larger, multicentre trials to validate these findings and assess the effect of low-pressure pneumoperitoneum on additional patient-reported outcomes and healthcare economics.