This prospective clinical study aimed to evaluate the effects of pneumoperitoneum and patient positioning on intracranial pressure in patients undergoing bariatric surgery. Intracranial pressure was assessed noninvasively using ultrasonographic optic nerve sheath diameter (ONSD) measurements. ONSD measurements were performed before anesthesia induction in the supine position (T0), 5 minutes after anesthesia induction (T1), 5 minutes after creation of pneumoperitoneum and placement in the reverse Trendelenburg position (T2), at the 20th minute of pneumoperitoneum (T3), and 5 minutes after termination of pneumoperitoneum and return to the supine position (T4). The study aimed to determine the effects of anesthesia, pneumoperitoneum, and surgical positioning on intracranial pressure during bariatric surgery

Obesity and bariatric surgery are associated with physiological changes that may influence intracranial pressure. Pneumoperitoneum and reverse Trendelenburg positioning, commonly used during laparoscopic bariatric surgery, can affect venous return, respiratory mechanics, and cerebral hemodynamics. Ultrasonographic measurement of optic nerve sheath diameter (ONSD) is a noninvasive and reliable method for estimating changes in intracranial pressure.

The aim of this prospective clinical study was to investigate the effects of anesthesia induction, pneumoperitoneum, and patient positioning on intracranial pressure in patients undergoing bariatric surgery. ONSD measurements were obtained at five predefined time points: before anesthesia induction in the supine position (T0), 5 minutes after anesthesia induction (T1), 5 minutes after creation of pneumoperitoneum and placement in the reverse Trendelenburg position (T2), at the 20th minute of pneumoperitoneum (T3), and 5 minutes after termination of pneumoperitoneum and return to the supine position (T4).

Hemodynamic parameters, end-tidal carbon dioxide levels, peak airway pressure, and plateau airway pressure were recorded simultaneously. The primary outcome was the change in ONSD measurements during different stages of the surgical procedure. The study sought to determine whether pneumoperitoneum and patient positioning contribute to changes in intracranial pressure during bariatric surgery.

Inclusion Criteria: The study will include patients who have undergone bariatric surgery, are over 18 years of age, and belong to the ASA 1-ASA 3 risk group.

Exclusion Criteria:Patients who do not wish to participate, those who have undergone cataract surgery, patients under 18 years of age, ASA 4 patients, patients with increased intracranial pressure, those with diseases that may cause increased intracranial pressure (hydrocephalus, stroke, brain tumor, etc.), those with eye pathology, and glaucoma patients will be excluded from the study. -

Adult patients undergoing bariatric surgery under general anesthesia at our institution. The study population consists of ASA I-III patients aged 18 years and older who underwent preoperative and perioperative optic nerve sheath diameter (ONSD) measurements at predefined time points during surgery.