Pitfalls in Expiratory Flow Limitation Assessment at Peak Exercise in Children: Role of Thoracic Gas Compression
Medicine and Science in Sports and Exercise
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Purpose: Thoracic gas compression and exercise-induced bronchodilation can influence the assessment of expiratory flow limitation (EFL) during cardiopulmonary exercise tests. The purpose of this study was to examine the effect of thoracic gas compression and exercise-induced bronchodilation on the assessment of EFL in children with and without obesity. Methods: Forty children (10.7 ± 1.0 yr; 27 obese; 15 with EFL) completed pulmonary function tests and incremental exercise tests. Inspiratory capacity maneuvers were performed during the incremental exercise test for the placement of tidal flow volume loops within the maximal expiratory flow volume (MEFV) loops, and EFL was calculated as the overlap between the tidal and the MEFV loops. MEFV loops were plotted with volume measured at the lung using plethysmography (MEFVp), with volume measured at the mouth using spirometry concurrent with measurements in the plethysmograph (MEFVm), and from spirometry before (MEFVpre) and after (MEFVpost) the incremental exercise test. Only the MEFVp loops were corrected for thoracic gas compression. Results: Not correcting for thoracic gas compression resulted in incorrect diagnosis of EFL in 23% of children at peak exercise. EFL was 26% ± 15% VT higher for MEFVm compared with MEFVp... (See full abstract in article).
Pediatric; Gas compression; Bronchodilation; Flow volume curve; Ventilatory constraint; Breathing mechanics
Wilhite, D. P.,
Babb, T. G.,
Bhammar, D. M.
Pitfalls in Expiratory Flow Limitation Assessment at Peak Exercise in Children: Role of Thoracic Gas Compression.
Medicine and Science in Sports and Exercise, 52(11),