Anesthetics and Cerebral Oxygenation in LSG

Obesity is a global health issue that affects different organ systems and may cause severe health issues. Patients with a BMI \> 40 kg/m2 or those with a BMI \> 35 kg/m2 with accompanying comorbidities are candidates for weight loss surgeries, which are generally referred to as bariatric surgeries. Laparoscopic sleeve gastrectomy (LSG) is a restrictive bariatric surgery procedure gaining increased popularity in the surgical treatment of morbid obesity. However, LSG requires a reverse-Trendelenburg position and prolonged pneumoperitoneum. Carbon dioxide pneumoperitoneum increases intracranial pressure (ICP) by increasing intra-abdominal pressure and by causing dilation of cerebral vessels through carbon dioxide reabsorption. Also, the reverse-Trendelenburg position decreases cardiac output and mean arterial pressure (MAP) by reducing cardiac venous return. A Near-infrared spectroscopy (NIRS) is a non-invasive technique and provides continuous monitoring of regional cerebral tissue oxygen saturation (rSO2). Sevoflurane and propofol are widely used for the maintenance of general anesthesia during bariatric surgery. Sevoflurane is an efficacious halogenated inhalational anesthetic for bariatric surgery because of its rapid and consistent recovery and because it does not cause hemodynamic instability because of its low blood solubility. Moreover, it increases global CBF through a direct intrinsic cerebral vasodilatory action and, in addition, it might improve cerebral oxygenation by decreasing the cerebral metabolic rate of oxygen (CMRO2) (luxury perfusion). Propofol can also be a suitable option for the maintenance of anesthesia in bariatric surgery. Propofol is a short-acting intravenous anesthetic agent with a very good recovery profile, and its elimination half-life and duration of action do not change in obese individuals. However, it has been reported that propofol may significantly decrease CBF by both suppressing CMRO2 and through a direct vasoconstrictive actio