title: [Effects of continuous positive airway pressure on daytime sleepiness in patients with severe obstructive sleep apnea syndrome].
abstract: OBJECTIVE
  To evaluate the effects of continuous positive airway pressure (CPAP) on daytime sleepiness in patients with severe obstructive sleep apnea syndrome (OSAS).
  
  
  METHODS
  Retrospective evaluations were performed for 70 consecutive patients at the medical sleep center, West China Hospital, Sichuan University from May 2013 to October 2013. They were all diagnosed with severe OSAS and underwent overnight CPAP titration. Their mean age and body mass index (BMI) were (42.7 ± 8.4) years and (29.2 ± 4.2) kg/m(2) respectively. The sleep structure, hypoxia and objective sleepiness was compared between baseline and CPAP titration. And correspondence analysis was performed between multiple sleep latency tests (MSLT) and other sleep and expiratory parameters.
  
  
  RESULTS
  Comparing to the baseline polysomnogram (PSG) levels, CPAP titration significantly decreased apnea hypopnea index (AHI) ((4.4 ± 2.7) vs (67.7 ± 18.9)/h), significantly shortened the longest apnea time (24.0 (16.5, 29.6) vs 61.3(51.0, 74.8) s) and raised the lowest oxygen saturation ((84.8 ± 8.8)% vs (54.4 ± 18.7)%).Furthermore, the percentage of stage 3 (N3%) (18.2(12.5, 25.6)% vs 2.4 (0.1, 8.2)%), the percentage of stage rapid eye movement (REM) sleep (REM%) ((22.3 ± 7.7)% vs (12.7 ± 5.8)%) and sleep perception improved significantly (89.1(88.3, 91.2)% vs 82.7(82.7, 87.0)%, all P < 0.05).Furthermore, CPAP also significantly improved their mean sleep latency of multiple sleep latency test (MSLT) ((8.5 ± 3.8) vs (4.8 ± 2.3) min, P < 0.05); the mean sleep latency of MSLT was negatively correlated with AHI, the percentage of stage 1 (N1%) and the longest apnea (r = -0.501,-0.308,-0.309,-0.501, all P < 0.01); but positively correlated with REM%, N3%, mean oxygen saturation and minimal oxygen saturation during CPAP titration (r = 0.235,0.394,0.398,0.440, all P < 0.05).
  
  
  CONCLUSIONS
  CPAP significantly improves nocturnal oxygen desaturation, sleep architecture and objective sleepiness in patients with severe OSAS.
authors.affiliation: Sleep Medicine Center, West China Hospital, Sichuan University, Chengdu 610041, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Pan
authors.forename: Rong
authors.initials: R
authors.lastname: Ren
authors.forename: Yun
authors.initials: Y
authors.lastname: Li
authors.forename: Liping
authors.initials: L
authors.lastname: Yang
authors.forename: Guoping
authors.initials: G
authors.lastname: Huang
authors.forename: Fei
authors.initials: F
authors.lastname: Lei
authors.forename: Lina
authors.initials: L
authors.lastname: Du
authors.affiliation: Email: xiangdong.tang@gmail.com.
authors.forename: Xiangdong
authors.initials: X
authors.lastname: Tang
mesh_terms: D000328:Adult; D045422:Continuous Positive Airway Pressure; D006801:Humans; D053609:Lethargy / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology* / Q000628:therapy*; D012894:Sleep Stages