Respiratory sleep disturbance in children and adolescents with cystic fibrosis
Revista Portuguesa de Pneumologia
Sleep disturbance has been described in cystic fibrosis (CF) patients as relevant to clinical and lung function predictive factors helping to improve the diagnosis and early intervention. Related paediatric studies are scarce. Objective: 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 SpO 2 are predictors of sleep disturbance. Methods: A cross-sectional
... : 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 (FEV 1 > −1.64 z-score); II ---Obstructed (FEV 1 ≤ −1.64 z-score). Results: 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 SpO 2 (95% (sd 2.7)) were normal; Abbreviations: AHI, apnoea/hypopnoea index; BMI, body mass index; CF, cystic fibrosis; CFTR, cystic fibrosis transmembrane condutance regulator; ERS, European Respiratory Society; FEF 25---75 , forced expiratory flow between 25% and 75% of maximal expiratory flow; FEV 1 , forced expiratory volume in 1 s; FL, flow limitation; FVC, forced vital capacity; HSM, Hospital de Santa Maria; N1, sleep stage 1; N1%TST, time in N1 as a percentage of total sleep time; N2, sleep stage 2; N2%TST, time in N2 as a percentage of total sleep time; N3, sleep stage 3; N3% TST, time in N3 as a percentage of total sleep time; NREM, non REM sleep; ODI, oxygen desaturation index; PSG, polysomnography; RDI, respiratory disturbance index; REM, rapid eye movement; REM%, time in REM as a percentage of total sleep time; REML, REM latency; RSD, respiratory sleep disturbance; SE, sleep efficiency; SL, sleep latency; SQ, sleep questionnaire; SpO 2 , pulse oximetry; SpO 2 mean, mean pulse oximetry value; SpO 2 min, minimal pulse oximetry value; tcCO 2 , transcutaneous CO 2 ; TST, total sleep time; W, wake; WASO, wake after sleep onset. Sleep disturbance in children and adolescents with cystic fibrosis 203 mean nocturnal oximetry desaturation index was 2.36/h; minimal nocturnal SpO 2 was 89% (sd 4.1). We found associations between mean nocturnal SPO 2 and mean values of FEV 1 (r = 0.528; p = 0.002) and FEF 25---75 (r = 0.426; p = 0.013). There were significant differences in nocturnal SpO 2 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 SpO 2 and spirometric values are possible risk predictors for nocturnal desaturation.