Background Children with Prader–Willi syndrome (PWS) are known to have sleep-disordered breathing. In addition to hypersomnolence and obstructive sleep apnoea, central respiratory control abnormalities may be present from infancy. The aims of this study were to describe breathing patterns in infants with PWS, and the effects of supplemental oxygen in this group.

Methods Children with PWS attending a tertiary sleep clinic underwent full polysomnographic studies either to investigate persisting neonatal oxygen requirement, or as screening for sleep-disordered breathing. Continuous oxygen saturations (SpO₂) and transcutaneous carbon dioxide (tcCO₂) were recorded. Central and obstructive events were defined in accordance with the American Academy of Sleep Medicine (AASM) 2007 scoring rules. Children who had significant hypoxia associated with central events were started on supplemental oxygen during sleep and followed at 3-monthly intervals with split-night studies (periods in both air and supplemental oxygen). Paired t-tests were used to compare sleep data in air and oxygen arms for our subject cohort.

Results 30 split-night studies were undertaken on 10 infants (8 female) aged 0.06–1.79 (mean 0.79, SD 0.44) years. At baseline (ie, air), children with PWS had a mean (SD) central apnoea index (CAI) of 6.9 (6.3) per hour, with accompanying falls in SpO₂. Oxygen therapy led to statistically significant reductions in CAI, as well as improved SpO₂ (Abstract P198 Table 1). No significant change in the number of obstructive events was noted.

Discussion Infants with PWS have sleep-disordered breathing problems, which are predominantly central in origin, and cause significant hypoxia in some patients. Improvements in both central event indices and oxygenation were noted on oxygen therapy. Longitudinal work with this patient group would help to establish timing of onset of obstructive symptoms. Whether early recognition of central hypoventilation, and correction with oxygen alter the evolution of respiratory dysfunction and excessive daytime somnolence in later life remains to be seen.