Effects of Pneumoperitoneum Pressure on Optic Nerve Sheath Diameter, Cerebral Oxygenation, and Postoperative Recovery During Laparoscopic Sleeve Gastrectomy: A Randomized Controlled Trial.

BACKGROUND

Carbon dioxide (CO₂) pneumoperitoneum during laparoscopic surgery may increase intracranial pressure by impairing cerebral venous drainage and inducing cerebral vasodilation. Patients with severe obesity may be particularly vulnerable due to obesity-related cardiopulmonary and hemodynamic alterations. This randomized controlled trial investigated the effects of standard- versus high-pressure pneumoperitoneum on optic nerve sheath diameter (ONSD), regional cerebral oxygen saturation (rSO₂), and postoperative recovery in patients undergoing laparoscopic sleeve gastrectomy (LSG).

METHODS

Sixty-three patients with severe obesity undergoing LSG were randomly allocated to standard-pressure pneumoperitoneum (PP12, 12 mmHg; n = 31) or high-pressure pneumoperitoneum (PP15, 15 mmHg; n = 32). The primary outcome was intraoperative change in ONSD, assessed by ultrasonography at predefined time points. Regional cerebral oxygen saturation was monitored continuously using near-infrared spectroscopy. Hemodynamic variables, PONV, pain scores, opioid requirements, and gastrointestinal recovery were also evaluated. Participants and postoperative assessors were blinded to group allocation.

RESULTS

ONSD increased during pneumoperitoneum in both groups, with significantly greater elevation in the PP15 group at 30 min. Cerebral oxygenation and hemodynamic parameters remained comparable throughout. The PP15 group experienced higher PONV rates, increased opioid consumption, greater postoperative pain scores, and delayed gastrointestinal recovery.

CONCLUSION

High-pressure pneumoperitoneum was associated with transient ONSD elevation and less favorable postoperative recovery despite preserved cerebral oxygenation. Low-pressure pneumoperitoneum may represent a simple, ERAS-compatible strategy to improve postoperative outcomes while maintaining cerebral safety in patients with severe obesity.