Functional respiratory imaging in obese children and adolescents with obstructive sleep apnea

Abstract

Introduction: Childhood obesity is associated with an increased prevalence of obstructive sleep apnea (OSA) and a less favourable outcome of adenotonsillectomy. In this study, we investigated if measurements of 3D-reconstructions of the upper airway (UA) paired with computational fluid dynamics (CFD) correlated with OSA severity. Methods: Obese children diagnosed with obstructive sleep apnea (OSA) by polysomnography were prospectively recruited. All underwent an ultra-low dose CT scan of the UA while being awake. 3D reconstructions were built from these images and were further analysed using CFD. Results: Thirty children were included (16 boys; mean age was 9.6±3.9 years, mean BMI was 28.1±6.8 kg/m2, median obstructieve apnea/hypopnea index (oAHI) 12.9(3.1-67.3)/hour. 19 children were diagnosed with moderate-to-severe OSA (oAHI > 5). No clear differences in UA volumes or resistance were observed between children with mild and severe OSA. There was a significant correlation between oAHI and effective volume of the UA (r=-0,44; p=0,03). The minimal area was located in the overlap region in 50% subjects with mild OSA and in 33% subjects with severe OSA ( p >0.05). There was no correlation between the clinical markers of UA patency (tonsil score and Mallampati score) and OSA severity. However, tonsil score correlated negatively with UA volumes and positively with UA resistance. There was a significant positive correlation between BMI and effective volume of the UA. Conclusions In this pilot study is a negative correlation between UA volume and OSA severity. The value of this technique in improving treatment outcome needs to be investigated further.