Discussion
daytime sleepiness, OSA, loop gain
EVENTS
This is a novel study in the perioperative setting to evaluate the efficacy of semi-upright position postoperatively for management of newly diagnosed OSA. We found that it is feasible to institute positional therapy in the form of semi-upright position in the postoperative period for OSA patients. The elevated position resulted in a significant reduction in OAI by eight events per hour, but not the AHI, CAI, HI, and OAHI. The lack of positive results in AHI may be because the patients in the intervention group had significantly worse OAI, lower SaOAlthough positive airway pressure (PAP) is the mainstay of treatment for moderate to severe OSA, perioperative adherence has been poor as studies have demonstrated only 34% CPAP adherence [Previous work has suggested that the semi-upright position significantly enlarges the upper airway dimensions [Body position may affect factors such as upper-airway passive collapsibility, airway dilator muscle activity, loop gain, and arousal threshold in patients with OSA [A retrospective study on OSA patients with upper airway surgery found that the prevalence of positional OSA increased from 26 to 54% in those with persistent OSA at six months [In a systematic review of positional therapy for OSA, CPAP was better than positional therapy to lower the AHI, while positional therapy was better than inactive controls to lower the AHI and improved daytime sleepiness [In the general population, patients with supine-related OSA may be a suitable phenotype to benefit from positional therapy [The limitations to our study were a small sample size with limited numbers in patients with supine-related OSA. Second, there can be variability in how the body position is reported and scored on the PSG. We used an accelerometer attached to the portable PSG which was placed on the patient′s chest. In-built automatic position sensors define body position as a categorical variable rather than a continuous variable, and may not reflect the physiological impact of various body positions on the collapsibility of the upper airway [