G274 Delta 12s index as a screening tool for obstructive sleep apnoea in children

Introduction and Aims Obstructive sleep apnoea (OSA) affects up to 5.7% of children and is associated with significant morbidity. Clinical assessment is subjective and an unreliable predictor of OSA.1 To date, no single parameter has been validated for predicting OSA in otherwise healthy children. The gold standard investigation in suspected OSA is polysomnography (PSG), which is labour- and resource-intensive, requires expert interpretation and can be poorly tolerated. Nocturnal oximetry studies are cost effective, widely available and well tolerated. Delta 12s, a measure of oxygen saturation variability in oximetry studies, has been validated for the prediction of OSA in adults2 and in children with Down’s syndrome3 but has not been studied in children without co-morbidities. We aimed to demonstrate whether the delta 12s index predicts OSA in children without Down’s syndrome. Methods We identified 500 sequential patients who underwent adeno-tonsillectomy at our centre from electronic records. Exclusion criteria were children with Down’s syndrome and those with no recorded oximetry study. It was then determined which of these children had OSA (defined as OSA diagnosed by an ENT surgeon or respiratory paediatrician, or an oxygen desaturation index ≥5). Delta 12s index derived from these children’s oximetry data was retrospectively analysed for its ability to predict OSA. Results 155/500 children met criteria for inclusion. In this sample, 78 were determined to have OSA and 19 were not. The remaining 58 were undetermined. The relationship between Delta 12s and OSA is highly significant (p Conclusion Delta 12s is a simple parameter that can be used by general paediatricians as a screening tool to identify symptomatic children without Down’s syndrome with a high likelihood of OSA. References Dehlink E, et al. J Thorac Dis. 2016; 8: 224–235. Magalang UJ, et al. Chest 2003;124:1694–707 Hill CM, et al. Arch Dis Child 2018;103:962–7