Thoracoabdominal asynchrony correlates with peripheral vascular resistance changes in a cohort of obese children

Objective: The purpose of this study was to assess the relationship between the thoracoabdominal asynchrony (phase angle), as an index of inspiratory airflow resistance, pulse transit time arousal index (PTT Ar/I), as changes in peripheral vascular resistance and intrathoracic pressure, and obstructive apnea index (OA), Oxygen Desaturation Index (ODI), snoring (% estimated Total Sleep Time - eTST) and apnea-hypopnea index (AHI) in a cohort of exogenous obese children. Material and Methods: Body mass index (BMI) and BMI z-scores were calculated according to age and sex in 36 consecutive obese children. Nasal patency, tonsil size, Friedman palate position scoring were also recorded. An overnight sleep respiratory recording was performed using an polygraphic ambulatory device. Results: Subjects studies had normal to mild sleep respiratory involvement (assessed by respiratory polysomnographic scoring). Phase angle correlated significantly with PTT Ar/I, but not with AHI (n/hr), OA (n/hr), ODI (n/hr) and snoring (% eTST), even adjusting for nasal patency, tonsil hypertrophy, palate position and BMI (z-score). Conclusion: Thoracoabdominal asynchrony (phase angle) is correlated with peripheral vascular resistance changes (PTT Ar/I), suggesting a subclinical upper respiratory airflow anomaly with autonomic activation in obese subjects.