Evaluation of the effects of different pneumoperitoneum pressures on cerebral oxygen consumption and optic nerve sheath diameter in laparoscopic bariatric surgeries

Obesity is a life-threatening chronic condition with increasing incidence. It is known that pneumoperitoneum used in laparoscopic surgeries can raise intracranial pressure. In this study, we aimed to evaluate the effects of different pneumoperitoneum pressures on optic nerve sheath diameter (ONSD), cerebral oximetry, hemodynamic parameters, postoperative nausea and vomiting (PONV), pain (NRS) scores, and gas passage in morbidly obese patients undergoing laparoscopic sleeve gastrectomy (LSG). The study was conducted on 70 patients between January 1, 2023, and June 30, 2023, after obtaining ethical approval. Patients were randomly divided into two groups: Group 1 with 12 mmHg (PP12) and Group 2 with 15 mmHg (PP15) pneumoperitoneum pressure. ONSD was measured using ultrasonography, and cerebral oximetry was assessed with a NIRS device. Hemodynamic parameters were monitored throughout the operation, while PONV, NRS scores, and gas passage were recorded in the postoperative period. Data were analyzed using SPSS software, with statistical significance set at p<0.05. In our study, a statistically significant increase in ONSD values was observed in the PP15 group compared to the PP12 group (p<0.05). However, no significant differences were found between the groups in terms of hemodynamic parameters (heart rate, mean arterial pressure, oxygen saturation) and cerebral oximetry values. The incidence of postoperative nausea and vomiting, as well as the amount of opioid analgesic used, was significantly higher in the PP15 group (p<0.05). Additionally, NRS pain scores were higher in the PP15 group, although this difference was not statistically significant. Gas passage was also delayed in the PP15 group, indicating a longer gastrointestinal recovery period. These findings suggest that higher pneumoperitoneum pressures may increase optic nerve sheath diameter, potentially associated with elevated intracranial pressure. Furthermore, higher pressure may negatively impact patients' postoperative recovery. We believe that careful monitoring and adjustment of pneumoperitoneum pressure are crucial for improving surgical outcomes Key words: Obesity, Pneumoperitoneum, ONSD, Cerebral Oximetry