Characteristics and feasibility of ambulatory respiratory assessment of paediatric neuromuscular disease: an observational retrospective study.

PURPOSE: To investigate the characteristics of respiratory involvement in Chinese paediatric neuromuscular disease (NMD) at early stage and to explore convenient monitoring methods. MATERIALS AND METHODS: Children with NMD (age < 18) diagnosed at a multidisciplinary joint NMD clinic at Peking University First Hospital from January 2016 to April 2021 were included. Overnight polysomnography (PSG) and pulmonary function test (PFT) data were analysed, and the characteristics of four groups: congenital muscular dystrophy (CMD), congenital myopathy, spinal muscular atrophy, and Duchenne muscular dystrophy (DMD) were compared. RESULTS: A total of 83 children with NMD were referred for respiratory assessment, of who 80 children underwent PSG; 41 performed spirometry and 38, both. The duration of pulse oxygen saturation (SpO2) <90% over apnoea and hypopnoea index (AHI) was lowest in DMD and significantly different from CMD (p = 0.033). AHI was positively correlated with the oxygen desaturation index (ODI) (r = 0.929, p = 0.000). The peak expiratory flow (PEF) were positively correlated with forced vital capacity (FVC), both as actual values and percent pred, respectively (r = 0.820, 0.719, p = 0.000). ROC derived sensitivity and specificity of prediction of AHI > 15/h or duration of SpO2<90% ≥ 60 min from FVC <51% pred was 75.8% and 85.7%, respectively. CONCLUSIONS: AHI and hypoxia burden were independent factors in children with NMD in PSG and attention needed to be paid in both. FVC might be a daytime predictor for significant sleep-disordered breathing or hypoxia. Nocturnal consecutive oximetry with diurnal peak flow measurement may be convenient and effective for home monitoring at early stage of respiratory involvement.