Predicting sleep-disordered breathing in patients with cystic fibrosis.
OBJECTIVE
To examine predictors of sleep-disordered breathing in patients with cystic fibrosis (CF) and moderate-to-severe lung disease using a comprehensive evaluation of both sleep and daytime function.


METHODS
Cross-sectional analysis of sleep studies, lung function, respiratory muscle strength, and evening and morning arterial blood gas measurements in patients with stable CF. A questionnaire addressing sleep quality was administered. Forward stepwise regression analysis was used to identify the parameters that best predict sleep-related desaturation, hypercapnia, and respiratory disturbance.


METHODS
Sleep investigation unit and lung function laboratory.


METHODS
Thirty-two patients with CF and FEV(1) < 65% predicted, in stable clinical condition. Patients were aged 27 +/- 8 years (mean +/- 1 SD) with FEV(1) of 36 +/- 10% predicted, evening PaO(2) of 68 +/- 8 mm Hg, and PaCO(2) of 43 +/- 5 mm Hg.


RESULTS
Evening PaO(2) (p < 0.0001) and morning PaCO(2) (p < 0.01) were predictive of the average minimum oxyhemoglobin saturation per 30-s epoch of sleep (r(2) = 0.74; p < 0.0001). Evening PaO(2) (p < 0.001) was predictive of the rise in transcutaneous carbon dioxide (TcCO(2)) seen from non-rapid eye movement (NREM) to rapid eye movement (REM) sleep (r(2) = 0.37; p < 0.001). In addition, there was some relationship between expiratory respiratory muscle strength and the REM respiratory disturbance index (r(2) = 0.22; p < 0.01).


CONCLUSIONS
Evening PaO(2) was found to contribute significantly to the ability to predict both sleep-related desaturation and the rise in TcCO(2) from NREM sleep to REM sleep in this subgroup of patients with CF.
Milross
M A
MA
Department of Respiratory Medicine, Royal Prince Alfred Hospital, Camperdown, Sydney.
Piper
A J
AJ
Norman
M
M
Willson
G N
GN
Grunstein
R R
RR
Sullivan
C E
CE
Bye
P T
PT
D000328:Adult; D001784:Blood Gas Analysis; D002940:Circadian Rhythm / Q000502:physiology; D003430:Cross-Sectional Studies; D003550:Cystic Fibrosis / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008168:Lung / Q000503:physiopathology; D008297:Male; D010108:Oxyhemoglobins / Q000378:metabolism; D017286:Polysomnography; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000503:physiopathology; D012894:Sleep Stages / Q000502:physiology
D010108:Oxyhemoglobins