39 Adherence to non-invasive ventilation in obese children with obstructive sleep apnoea or obesity hypoventilation syndrome

Introduction This study aimed to describe the cohort of obese children who were on respiratory support for obstructive sleep apnoea (OSA) or nocturnal hypoventilation in a tertiary respiratory centre and their adherence at 1 year. Methods Clinical and cardiorespiratory polygraphy data were reviewed for children with a body mass index (BMI) >25kg/m2 established on NIV for OSA (AHI>1ev/Hr) or OHS (BMI>30kg/m2 and criteria for nocturnal hypoventilation)1 from 2013–21. Children with neuro-disability were excluded. Nocturnal hypoventilation was defined as transcutaneous carbon dioxide (TCO2) >6.7kPa ≥ 25% total sleep time (TST).1 Studies less than 4 hours TST were excluded. Day time hypercapnia was defined as TCO2 >5.99kPa ≥10 minutes.1 NIV compliance was >4 hours/night use for >70% of nights.2 Results Data was obtained from 16 children (9 males, 7 females) of whom 2 children had a BMI of 25-30kg/m2, and 14 > 30Kg/m2. Baseline polygraphy data was available on 13/16 children, 8 children had OSA only, 3 had OSA and nocturnal hypoventilation and 2 had and isolated OHS. 5 children (3M, 2F, age 9.0 (4.5-16) years) had nocturnal hypoventilation and also had the highest BMI of the cohort, BMI median 36.2 (28.6-47.3) kg/m2. Daytime hypercapnia was present in 4/9 children with measurements, but only 2 had nocturnal hypoventilation. No child had a TCO2 increase >10mmHg from wake to sleep. Children were established on NIV continuous (n=11) and bilevel (n=5). Only 2/14 children with adherence data were adherent to respiratory support at 1 year. (Table 1). Discussion Assessment for complications of excess weight should include day and night-time TCO2 monitoring as OHS was evident from 5 years. Adherence to NIV is poor and intensive multi-disciplinary input may improve this. References Masa Eur Respir Rev 2019. Schwab Am J Respir Crit Care Med 2013.