Impact of Different Pneumoperitoneum Pressures on Internal Carotid Artery Blood Flow and Cerebral Oxygenation in Laparoscopic Sleeve Gastrectomy

Abstract Background High intra-abdominal pressure (IAP) during bariatric surgery may compromise cerebral perfusion. This study evaluates the impact of 12 vs. 16 mmHg pneumoperitoneum on internal carotid artery (ICA) hemodynamics and cerebral oxygenation (rSO 2 ) in patients with severe obesity undergoing laparoscopic sleeve gastrectomy (LSG). Methods In this prospective, randomized, double-blind study, 67 patients undergoing LSG were allocated into two groups: Group 12 (12 mmHg, n = 34) and Group 16 (16 mmHg, n = 33). Internal carotid artery velocity-time integral (VTI), internal carotid artery blood flow (ICABF), and rSO 2 were recorded at seven time points (T 0 to T 6 ). Acute positional and cumulative pressure effects were analyzed using delta (Δ) change values. Results Systemic hemodynamics remained stable across groups ( P > 0.05). However, Group 16 showed significantly greater cumulative reductions in both ICA-VTI and ICABF compared to Group 12, particularly during the T 0 –T 6 period ( P < 0.001). Specifically, the decline in ICABF for Group 16 was significantly more pronounced at T 0 –T 6 (-161.89 vs. -107.41; P = 0.004) and T 2 –T 4 (-87.95 vs. -72.06; P = 0.036). The combined effect of pneumoperitoneum and reverse Trendelenburg position (T 2 –T 3 ) induced a significantly greater acute reduction in rSO 2 in Group 16 (Δ: -1.82) than in Group 12 (Δ: -0.24; P = 0.029). Conclusion Elevated 16 mmHg IAP exerts a subclinical hemodynamic burden by straining cerebral reserves through cumulative ICABF reduction and acute rSO 2 declines. An initial pressure of 12 mmHg may be recommended to optimize neuro-hemodynamic stability, with subsequent adjustments tailored to surgical requirements and patient needs.