Are COPD patients with nocturnal REM sleep-related desaturations more prone to developing chronic respiratory failure requiring long-term oxygen therapy?
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.
Sergi
Margherita
M
Respiratory Function Laboratory, S. Maugeri Foundation, Montescano Medical Center, I-27040 Montescano (PV), Italy.
Rizzi
Maurizio
M
Andreoli
Arnaldo
A
Pecis
Marica
M
Bruschi
Claudio
C
Fanfulla
Francesco
F
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*
D010100:Oxygen