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 action. The impact of
propofol on global CBF is more salient than that on CMRO2, resulting in a decrease in rSO2.
The aim of the present study was to test the hypothesis that rSO2 is better preserved with
sevoflurane than propofol in morbidly obese patients who have undergone LSG.