title: The Severity of Sleep Disordered Breathing Induces Different Decrease in the Oxygen Saturation During Rapid Eye Movement and Non-Rapid Eye Movement Sleep.
abstract: OBJECTIVE
  To investigate how differences in oxygen saturation between non-REM (NREM) and REM sleep in patients according to the severity of sleep apnea.
  
  
  METHODS
  We studied 396 male patients diagnosed with simple snoring or obstructive sleep apnea syndrome (OSAS) on nocturnal polysomnography. Patients were divided into groups by the OSAS severity. We compared the average oxygen saturation between REM and NREM sleep in each group.
  
  
  RESULTS
  In the simple snoring group, average oxygen saturation was significantly greater during REM than during NREM sleep. In the severe OSA group alone, average oxygen saturation was greater in NREM than in REM sleep. The difference of NREM-REM average oxygen saturation correlated significantly with AHI in the severe OSA group.
  
  
  CONCLUSIONS
  More severe hypoxemia was seen in REM than NREM sleep in the severe OSAS group. The differential oxygen decrease between REM and NREM sleep is likely due to the differentially occurring sleep breathing events in each sleep stage according to the SDB severity. The more AHI increases in the severe OSAS patients, the more prominent the hypoxemia of REM sleep compared with NREM sleep is likely to appear. This suggests that the pressure of continuous positive airway pressure should be increased to control the hypoxemia of REM sleep in extremely severe OSAS.
authors.affiliation: Department of Psychiatry, School of Medicine Konkuk University, Seoul, Republic of Korea.
authors.forename: Eunkyung
authors.initials: E
authors.lastname: Choi
authors.affiliation: Department of Psychiatry, School of Medicine Konkuk University, Seoul, Republic of Korea.
authors.forename: Doo-Heum
authors.initials: DH
authors.lastname: Park
authors.affiliation: Department of Psychiatry, School of Medicine Konkuk University, Seoul, Republic of Korea.
authors.forename: Jae-Hak
authors.initials: JH
authors.lastname: Yu
authors.affiliation: Department of Psychiatry, School of Medicine Konkuk University, Seoul, Republic of Korea.
authors.forename: Seung-Ho
authors.initials: SH
authors.lastname: Ryu
authors.affiliation: Department of Psychiatry, School of Medicine Konkuk University, Seoul, Republic of Korea.
authors.forename: Ji-Hyeon
authors.initials: JH
authors.lastname: Ha
keywords: Non-REM sleep; Obstructive sleep apnea; Oxygen saturation; REM sleep; Sleep disordered breathing