Introduction
Given the well-recognized coexistence of sleep-disordered breathing and obstructive lung diseases such as COPD and asthma , it is not surprising that sleep-disordered breathing also coexists with cystic fibrosis (CF).1-4 Sleep architecture, the cyclical pattern of sleep between different sleep stages, is similar in CF patients compared to normal controls; however, CF patients have impaired subjective sleep quality.5 Poor sleep quality can be due to upper airway disease such as sinus disease, structural lung disease, chronic cough, use of medications including opioids, and the prevalence of sleep-disordered breathing.6 Sleep-disordered breathing encompasses a broad spectrum of respiratory abnormalities during sleep, ranging from primary snoring, respiratory event related arousals (RERAs), nocturnal hypoxia, obstructive sleep apnea (OSA), and hypoventilation. Primary snoring does not have physiological consequences; however, other respiratory abnormalities during sleep, especially OSA, can have significant deleterious effects.
Untreated sleep-disordered breathing can adversely affect outcomes in patients with chronic lung disease7, and therefore it is essential that CF clinicians expeditiously screen, diagnose, and treat sleep-disordered breathing in the CF population. In this review, we focus on three clinically relevant categories of sleep-disordered breathing: nocturnal hypoxemia, obstructive sleep apnea, and nocturnal hypoventilation.8 We will also discuss proposed areas for future research, and suggest key practical take home points for the non- sleep trained CF clinician.
We acknowledge that other sleep disorders such as insomnia, periodic leg movements and circadian rhythm disturbances are prevalent in individuals with CF, but these are outside the scope of this review. In addition, we will not be covering respiratory related arousals and central sleep apnea, as little is known about these conditions as it specifically applies to the CF population9.