Breathing irregularity during wakefulness associates with CPAP acceptance in sleep apnea.
OBJECTIVE
Individuals have different breathing patterns at rest, during wakefulness, and during sleep, and patients with sleep apnea are no different. The hypothesis for this study was that breathing irregularity during wakefulness associates with CPAP acceptance in obstructive sleep apnea (OSA).


METHODS
From a 2007-2010-database of patients with a diagnostic polysomnography (PSG) and prescribed CPAP (n = 380), retrospectively, 66 patients who quit CPAP treatment at 6 months were identified. Among them, 27 OSA patients quit despite having no side effects for discontinuing CPAP (Group A) and were compared to a matched group (age, body mass index, and apnea-hypopnea index) with good 6-month CPAP adherence (Group B; n = 21). Five minutes of respiratory signal during wakefulness at the initial PSG were extracted from respiratory inductance plethysmography recordings, and measured in a blinded fashion. The coefficients of variation (CV) for the breath-to-breath inspiration time (T i), expiration time (T e), T i + T e (T tot), and relative tidal volume, as well as an independent information theory-based metric of signal pattern variability (mutual information) were compared between groups.


RESULTS
The CV for tidal volume was significantly greater (p = 0.001), and mutual information was significantly lower (p = 0.041) in Group A as compared to Group B.


CONCLUSIONS
Differences in two independent measures of breathing irregularity correlated with CPAP rejection in OSA patients without nasal symptoms or comorbidity. Prospective studies of adherence should examine traits of breathing stability.
Second Department of Internal Medicine (Department of Respiratory Medicine), Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8522, Japan. mountain@pastel.ocn.ne.jp
Motoo
M
Yamauchi
Frank J
FJ
Jacono
Yukio
Y
Fujita
Masanori
M
Yoshikawa
Yoshinobu
Y
Ohnishi
Hiroshi
H
Nakano
Cara K
CK
Campanaro
Kenneth A
KA
Loparo
Kingman P
KP
Strohl
Hiroshi
H
Kimura
D000328:Adult; D000368:Aged; D045422:Continuous Positive Airway Pressure; D045853:Exhalation; D005260:Female; D006801:Humans; D001239:Inhalation; D008297:Male; D008875:Middle Aged; D010342:Patient Acceptance of Health Care; D010352:Patient Dropouts; D017286:Polysomnography; D012119:Respiration; D012189:Retrospective Studies; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis / Q000523:psychology / Q000628:therapy*; D013223:Statistics as Topic; D013990:Tidal Volume; D014851:Wakefulness