Optic Nerve Sheath Diameter and Cognitive Outcomes in Bentall Surgery

Bentall surgery is a major cardiac procedure involving replacement of the ascending aorta, aortic root, and aortic valve, typically requiring cardiopulmonary bypass (CPB) and sometimes deep hypothermic circulatory arrest (DHCA). Due to its complexity, it carries a significant risk of postoperative neurological complications including stroke and postoperative cognitive dysfunction (POCD). This prospective observational study aims to evaluate the relationship between perioperative bilateral optic nerve sheath diameter (ONSD) measurements obtained by ultrasound and postoperative cognitive functions in patients undergoing elective Bentall surgery. ONSD is a non-invasive surrogate marker of intracranial pressure that can be measured at the bedside using ultrasound. In addition to routine hemodynamic monitoring and cerebral oximetry (NIRS), bilateral ONSD will be measured at predefined intraoperative and postoperative time points. Cognitive function will be assessed using the Montreal Cognitive Assessment (MoCA) test preoperatively and postoperatively, and delirium will be evaluated using the CAM-ICU scale during ICU stay. The association between perioperative ONSD values and postoperative cognitive outcomes, extubation time, ICU stay, and neurological complications will be analyzed.