Multimodal perioperative monitoring of intracranial pressure surrogates and cerebral oxygenation during laparoscopic surgery: implications for early cognitive outcomes

Purpose: Pneumoperitoneum during laparoscopic abdominal surgery increases intra-abdominal pressure (IAP), potentially affecting intracranial pressure (ICP) and cerebral oxygenation. The clinical relevance of these changes, particularly regarding early postoperative cognitive dysfunction (POCD), remains unclear. This study aimed to evaluate perioperative changes in optic nerve sheath diameter (ONSD) and regional cerebral oxygen saturation (rSO₂) using noninvasive monitoring techniques. Methods: This prospective observational study included 50 ASA I–III patients aged 20–60 years undergoing laparoscopic abdominal surgery under general anesthesia. Bilateral ONSD and rSO₂ were measured at five time points: before induction (T0), 5 minutes after induction (T1), 5 minutes after CO₂ pneumoperitoneum (T2), 30 minutes after pneumoperitoneum (T3), and 5 minutes after desufflation (T4). IAP was assessed using intravesical measurements and insufflator readings. Cognitive function was evaluated with the Mini-Mental State Examination (MMSE) preoperatively and 24 hours postoperatively. Hemodynamic and airway parameters were recorded concurrently. Results: ONSD increased significantly after pneumoperitoneum, peaking at T3 (6.15 ± 0.06 mm, p < 0.001), and returned toward baseline after desufflation. rSO₂ increased after induction, showed a transient decrease at T2, and subsequently recovered ( p < 0.05). No consistent correlation was observed between ONSD and rSO₂. Intravesical IAP values were higher than insufflator readings at T2–T3 ( p < 0.05). POCD occurred in 24% of patients and was more frequent in those with higher BMI or lower educational level, without association with ONSD or rSO₂ changes. Conclusions: CO₂ pneumoperitoneum caused transient increases in ONSD and mild, reversible changes in cerebral oxygenation. Early POCD was more closely related to baseline patient characteristics than perioperative cerebral monitoring variables. ClinicalTrials.gov ID: NCT07264764 Registration date: 24 November 2025