title: [Respiratory control during sleep and the development of nocturnal hypoxia in patients with obstructive sleep apnea hypopnea syndrome].
abstract: OBJECTIVE
  It is assumed that the reduced ventilatory control during sleep may be related to the nocturnal hypoxia in patients with obstructive sleep apnea hypopnea syndrome (OSAHS) and daytime CO(2) retention.
  
  
  METHODS
  Oxygen desaturation index (ODI(4)), sleep time spent when SaO(2) was below 90% (SIT(90)), the lowest SaO(2) (LSaO(2)) and the mean SaO(2) (MSaO(2)) during sleep were measured in 24 OSAHS patients with daytime PaCO(2) > or = 45 mm Hg and 39 with PaCO(2) < 45 mm Hg. Hypoxic (DeltaP(0.1)/DeltaSaO(2)) and hypercapnic (DeltaP(0.1)/DeltaPaCO(2)) responsiveness were measured in 11 eucapnic and 4 hypercapnic patients during wakefulness, NREM and REM sleep stages.
  
  
  RESULTS
  Compared with the eucapnic patients, all the hypercapnic patients had more severe hypoxia during sleep (P < 0.05). Although both groups had similar chemical responsiveness during wakefulness, the hypercapnic patients had lower DeltaP(0.1)/DeltaSaO(2) and DeltaP(0.1)/DeltaPaCO(2) during both REM and NREM sleep (P < 0.05).
  
  
  CONCLUSIONS
  The depressed chemical responsiveness during sleep plays an important role in the development of nocturnal hypoxia in OSAHS patients with daytime CO(2) retention.
authors.affiliation: Department of Respiratory Medicine, Peking University People's Hospital, Beijing 100044, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Han
authors.forename: Hai-lin
authors.initials: HL
authors.lastname: Wei
authors.forename: Yong-hui
authors.initials: YH
authors.lastname: Zhang
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Xiao-song
authors.initials: XS
authors.lastname: Dong
authors.forename: Quan-ying
authors.initials: QY
authors.lastname: He
authors.forename: Er-zhang
authors.initials: EZ
authors.lastname: Chen
authors.forename: Dong-jie
authors.initials: DJ
authors.lastname: Ding
mesh_terms: D002245:Carbon Dioxide / Q000097:blood; D006801:Humans; D000860:Hypoxia / Q000209:etiology*; D010100:Oxygen / Q000097:blood; D012119:Respiration; D012890:Sleep / Q000502:physiology*; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology*
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen