To describe respiratory sleep disturbance (RSD) and its association with spirometric indices in a population of CF children. A second aim was to determine if spirometric indices and wake-time SpO2 are predictors of sleep disturbance.
A cross-sectional study involving 33CF paediatric patients. All participants underwent in-lab polysomnography (PSG), pulse oximetry and spirometry. A standardized sleep questionnaire was completed for each patient. Two subgroups were considered: I – Normal (FEV1 > −1.64 z-score); II – Obstructed (FEV1 ≤ −1.64 z-score).
Participant's median age was 12 (6–18) years, 16 (48.5%) were male. Twenty-nine patients (87.9%) presented sleep complaints. Sleep efficiency was reduced; sleep latency and waking after sleep onset (WASO) increased. N1 increased, N2, N3, REM and awakenings were normal. The apnoea–hypopnoea index was 0.6/h (sd 0.9); respiratory disturbance index (RDI) was 6.6/h (sd 5.2). Mean awaking (97% (sd 1.1)) and sleep SpO2 (95% (sd 2.7)) were normal; mean nocturnal oximetry desaturation index was 2.36/h; minimal nocturnal SpO2 was 89% (sd 4.1).
We found associations between mean nocturnal SPO2 and mean values of FEV1 (r = 0.528; p = 0.002) and FEF25–75 (r = 0.426; p = 0.013). There were significant differences in nocturnal SpO2 between normal and obstructed patients (p < 0.000). PSG data correlated with the questionnaire answers for night awakenings and WASO (p = 0.985) and difficult breathing during sleep and RDI (p = 0.722).
This study points to most CF children having sleep complaints, and highlights the correlation between subjective assessment of sleep and PSG and spirometric results. Awake-time SpO2 and spirometric values are possible risk predictors for nocturnal desaturation.