Rapid eye movement and slow-wave sleep rebound after one night of continuous positive airway pressure for obstructive sleep apnoea

Background and objective: Rebound of slow-wave sleep (SWS) and rapid eye movement (REM) sleep is observed in patients who are on continuous positive airway pressure (CPAP) therapy for obstructive sleep apnoea (OSA); but, neither have been objectively defined. The pressure titration study often represents the first recovery sleep period for patients with OSA. Our aim was to objectively define and identify predictors of SWS and REM sleep rebound following CPAP titration. Methods: Paired diagnostic polysomnography and pressure titration studies from 335 patients were reviewed. Results: The mean apnoea-hypopnoea index was 40.7 +/- 26.1, and minimum oxygen saturation was 76 +/- 14.4%. Comparing eight incremental thresholds, a rebound of 20% in REM sleep and a 40% increase in SWS allowed the best separation of prediction models. A 20% rebound in REM sleep was predicted by REM sleep %, non-REM arousal index (ArI) and total sleep time during diagnostic polysomnography, and male gender (R-2 = 35.3%). A 40% rebound in SWS was predicted by SWS %, total ArI and REM sleep % during diagnostic polysomnography, and body mass index (R-2 = 45.4%). Conclusions: A 40% rebound in SWS, but only a 20% rebound in REM sleep on the pressure titration study, is predicted by abnormal sleep architecture and sleep fragmentation prior to the commencement of treatment.