Thoracoabdominal Asynchrony in Healthy Children.

Measuring asynchrony between the thorax and abdomen during sleep provides information about inspiratory effort and upper airway obstruction in children, aiding in the diagnosis of obstructive sleep apnea (OSA). This study aimed to define a normative range for thoracoabdominal asynchrony (TAA) in healthy children by studying polysomnographies of 113 children aged 10-13 years. The percentage of total sleep time (TST) spent with elevated TAA, > 40°, was measured, as well as obstructive apnea-hypopnea index (OAHI), sleep position, sleep stage and snoring. Subjects without measurable OSA (N = 94) were defined as healthy subjects and they had elevated TAA for an average of 3.3% of their TST while subjects with OSA (N = 19) had elevated TAA for 10.7% of their TST (p < 0.00001). The cut-off point for the normal prevalence of elevated TAA was estimated at 9.6% of TST, which can be rounded up to 10% for ease of use. TAA prevalence rose in REM-sleep and in the supine position and was related to increased snoring. Children with obesity had higher OAHI, more prevalent TAA and more snoring. No gender differences were observed. Parent-reported PSQ scores showed limited concordance with objective measures. TAA assessment, available from standard RIP-bands placed around chest and abdomen, may aid in the interpretation of sleep studies in children, both home sleep apnea tests and polysomnographies. With further research, they might help guide clinical decision making in paediatric sleep medicine.