Comparing upper airway awake exploration, drug-induced sleep endoscopy and natural sleep—a systematic review

Background: The optimal exploration of a patient suffering from obstructive sleep apnea (OSA) should be performed during natural sleep. Nevertheless, this is not feasible in everyday clinical practice, therefore, OSA patients are explored awake and during drug-induced sleep endoscopy (DISE). Maneuvers performed in the awake exploration cannot represent what occurs during natural sleep due to the reduced pharyngeal muscle tone, regardless, there are doubts regarding the validity of DISE. The goal of this paper is to compare natural sleep and DISE and to find out whether DISE provides additional information to awake exploration. Methods: A systematic review of the literature comparing DISE, natural sleep, and awake exploration. Thirty-six studies were finally included. Results: According to the literature review, DISE is comparable to natural sleep when midazolam or propofol with a target-controlled infusion pump is administrated. Articles comparing propofol and dexmedetomidine sedation in the same group of patients at the same level of sedation found that the effect on the upper airway (UA) was similar for both drugs. Although no articles comparing dexmedetomidine and natural sleep have been found, one would assume that it is also a suitable drug for sedation. Regarding awake UA exploration, the results are inconclusive, but the simulated snoring maneuver appears to reflect DISE findings better. Conclusions: Evidence supports the use of DISE as a tool to explore OSA patients in a similar state to natural sleep, whereas awake exploration has limitations in predicting DISE collapse.