Nocturnal oximetry in bariatric surgery patients referred to overnight in‐lab polysomnography

Abstract

Obstructive sleep apnea (OSA) is an extremely common disease characterized by the presence of recurrent obstructive episodes in the upper airways during sleep, promoting the occurrence of intermittent hypoxemia and sleep fragmentation (1,2). The pathogenesis of OSA is multifactorial, with obesity playing a role as a preponderant risk factor (3-5). Therefore, it is not surprising that individuals with obesity undergoing preoperative evaluation as candidates for bariatric surgery exhibit a very high prevalence of OSA (6-10).Overnight in-lab polysomnography (PSG) remains the reference standard for the OSA diagnosis; however, it is expensive and not widely available (2). In light of such considerations, increased interest in nocturnal oximetry has developed because it is more comfortable and can be performed at home, is markedly less onerous, and is widely available compared with PSG. Overnight drops in oxygen saturation (SpO 2 ) are one of the characteristic hallmarks of individuals suffering from OSA. The repetitive nocturnal hypoxemia in OSA elicits oxidative stress and inflammation which act as the major contributors to the pathogenesis of the aforementioned endorgan morbidities, indicating that oxygenation parameters should be used to describe a different phenotype in .Among the various parameters derived from pulse oximetry recordings, the oxygen desaturation index (ODI), which is a measure of the number of times that a drop in SpO 2 (usually 3% or 4%) is observed per hour of sleep, is the most frequently used (17-26). Indeed,