Respiratory Function and Sleep Disordered Breathing in Pediatric Duchenne Muscular Dystrophy

BACKGROUND: The decline of respiratory function in Duchenne muscular dystrophy (DMD) is associated with sleep disordered breathing (SDB) and alteration of nocturnal gas exchange, first manifesting as nocturnal hypoventilation (NH). However, the correlation between pulmonary function measured by spirometry (PFT) and the onset of SDB with or without NH is unclear. AIM: To identify the prevalence and features of SDB and to investigate the relationship between lung function determined by forced vital capacity (FVC) and sleep abnormalities in a large paediatric DMD population. METHODS: Retrospective, single-center cohort study. FVC% predicted (FVC%) was calculated using predicted equations from the Global Lung Function Initiative. NH was defined by transcutaneous (tc) CO2 >50 mmHg for >25% of total sleep time (TST); borderline NH by a mean tcCO2 between 45-50mmHg or tcCO2>50mmHg for ≤25% of TST; Clinically meaningful obstructive sleep apnea (OSA) by obstructive Apnea-Hypopnea Index >5. The sensitivity, specificity, positive and negative predictive value of FVC50%. Seventeen/26 patients with OSA presented with concomitant NH or borderline NH. FVC50%. These results are relevant for the clinical management of SDB