Can be compared obstructive respiratory events during drug induced sleep endoscopy (DISE) and nocturnal polysomnography

Purpose Obstructive sleep apnea (OSA) is a collapse of pharynx muscles during sleep that can cause obstruction in the upper airway. It is better to determine the site and pattern of obstruction in the upper airway with drug-induced sleep endoscopy (DISE) before surgery. OSA usually occurs in a non-rapid eye movement (NREM) sleep and sometimes it gets longer and more intense in REM; hence, the study is meant to explore whether the sleep stage and results in DISE may have any similarity with usual nocturnal polysomnography or not. Materials and methods In this study, 38 patients with OSA diagnosed on the basis of polysomnography, underwent DISE. Moreover, EEG (12 channels), pulse oximetry and effort channel (respiratory inductance plethysmography) were recorded during DISE to determine the sleep stage and mean respiratory event duration (MRED). Results Thirty-eight patients were enrolled in this study. Eighty-four percent (84%) of obstructive respiratory events were observed in NREM sleep in Lab-PSG and 71% in DISE. 28.9% of patients’ events occurred in the wake state in DISE. The mean respiratory event duration (MRED) values in DISE and nighttime sleep were 24.5 ± 7.5 s and 25.4 ± 7.7 s, respectively without significant difference ( P value = 0.744), while the minimum values for SPO 2 were 74.0 ± 17.3 and 73.6 ± 20.3, respectively ( P = 0.885). Conclusions Considering the fact that the majority of respiratory events occurred in NREM sleep stage in both PSG and DISE, DISE results can be trusted. Due to absence of REM stage in DISE, the level of the obstruction may mislead the surgeon.