title: Are COPD patients with nocturnal REM sleep-related desaturations more prone to developing chronic respiratory failure requiring long-term oxygen therapy?
abstract: BACKGROUND
  Nocturnal oxygen desaturations (NOD), especially during REM sleep, have been described in patients with COPD. However, the role of NOD in the evolution of COPD to chronic respiratory failure has not been well studied.
  
  
  OBJECTIVE
  The aim of our study was to evaluate whether NOD is a risk factor for the development of chronic respiratory failure in COPD patients.
  
  
  METHODS
  We studied 34 consecutive COPD patients with a stable daytime PaO(2) >60 mm Hg over a period of 42 months. We classified patients as desaturators (NOD) when episodic desaturations were found mainly during REM sleep, independently of baseline SaO(2) values.
  
  
  RESULTS
  At enrollment 19 patients (55.8%) had NOD. Over the follow-up period, 10 patients (29.4%) were included in a long-term oxygen therapy (LTOT) programme (9 were desaturators). The LTOT was initiated a median time of 22 +/- 6.8 months after enrollment. Patients who were subsequently prescribed LTOT had lower values of FEV(1) at enrollment, with a higher degree of NOD and PaCO(2). Stable respiratory failure developed earlier in patients with NOD: the two enrollment curves for LTOT differed significantly (log-rank test 2.56, p = 0.005). PaCO(2), NOD and FEV(1) were statistically significantly associated, both in univariate and multivariate Cox proportional hazards analyses, with an increased risk of entering a LTOT programme.
  
  
  CONCLUSIONS
  We conclude that NOD may represent an independent risk factor for the development of chronic respiratory failure in COPD patients with daytime PaO(2) >60 mm Hg. A larger study is needed to confirm the role of NOD in the natural history of COPD and subsequently to identify the most appropriate therapeutic approach.
authors.affiliation: Respiratory Function Laboratory, S. Maugeri Foundation, Montescano Medical Center, I-27040 Montescano (PV), Italy.
authors.forename: Margherita
authors.initials: M
authors.lastname: Sergi
authors.forename: Maurizio
authors.initials: M
authors.lastname: Rizzi
authors.forename: Arnaldo
authors.initials: A
authors.lastname: Andreoli
authors.forename: Marica
authors.initials: M
authors.lastname: Pecis
authors.forename: Claudio
authors.initials: C
authors.lastname: Bruschi
authors.forename: Francesco
authors.initials: F
authors.lastname: Fanfulla
mesh_terms: D000368:Aged; D018450:Disease Progression; D006801:Humans; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D010102:Oxygen Inhalation Therapy; D017286:Polysomnography; D016016:Proportional Hazards Models; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood / Q000503:physiopathology*; D012129:Respiratory Function Tests; D012131:Respiratory Insufficiency / Q000628:therapy*; D012307:Risk Factors; D012895:Sleep, REM / Q000502:physiology*
chemical_list: D010100:Oxygen