@article {AbelPA4357, author = {Francois Abel and Hui-Leng Tan and Aidan Laverty and Valentina Negro and Nicola Bridges and Thomas Carlisle and Elaine Chan and Michael Miligkos and Martin Samuels and Athanasios G. Kaditis}, title = {Sleep-related hypoventilation in children with Prader-Willi syndrome: Experience from two UK paediatric sleep centres}, volume = {48}, number = {suppl 60}, elocation-id = {PA4357}, year = {2016}, doi = {10.1183/13993003.congress-2016.PA4357}, publisher = {European Respiratory Society}, abstract = {Although most children with Prader-Willi syndrome (PWS) have obstructive sleep apnoea syndrome (OSAS), the prevalence of sleep-related hypoventilation is unknown. We hypothesized that children with PWS have hypercapnia for higher proportion of sleep time (ST) than age- and BMI-matched control children with similar obstructive apnoea-hypopnoea index (OAHI).Methods: Children with PWS undergoing nocturnal polygraphy prior to growth hormone commencement were matched for age, BMI z-score and OAHI to otherwise healthy children with snoring, adenotonsillar hypertrophy and/or obesity. The interaction between PWS diagnosis and OSAS severity (OAHI\>5/h vs. <=5/h) regarding their effect on \%ST with transcutaneous CO2(PtcCO2)\>45 mmHg was explored using a general linear model.Results: 48 children with PWS and 93 controls were included (3.9{\textpm}4.1 y.o. vs. 4.1{\textpm}4 y.o.; BMI z-score 0.73{\textpm}1.91 vs. 0.78{\textpm}1.66; OAHI 3.2{\textpm}6.7 vs. 2.7{\textpm}6.2/h, respectively; P\>0.05 for all). For OAHI\>5, children with PWS and controls had greater difference in \%ST with PtcCO2\>45 (PWS: 76.6{\textpm}24.7\% vs. controls: 40.3{\textpm}37.2\%) than for OAHI<=5 (PWS: 22.6{\textpm}32.1\% vs. controls: 17.9{\textpm}27.1\%). More specifically, the interaction between PWS and OSAS severity regarding their effect on \%ST with PtcCO2\>45 was significant after adjustment for age, gender and BMI z-score (P=0.03). Results did not change when hypoventilation was defined as PtcCO2\>50 mmHg.Conclusion: During sleep, children with PWS and OSAS hypoventilate disproportionately to the degree of upper airway obstruction. This has potential pathophysiological implications but also demonstrates that simple oximetry studies are inadequate to monitor this group of patients.}, issn = {0903-1936}, URL = {https://erj.ersjournals.com/content/48/suppl_60/PA4357}, eprint = {https://erj.ersjournals.com/content}, journal = {European Respiratory Journal} }