Pitfalls in Expiratory Flow Limitation Assessment at Peak Exercise in Children: Role of Thoracic Gas Compression.
Pitfalls in Expiratory Flow Limitation Assessment at Peak Exercise in Children: Role of Thoracic Gas Compression.
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DOI：
10.1249/mss.0000000000002378
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发表时间：
2020-11
影响因子：
4.1
通讯作者：
Bhammar DM
中科院分区：
文献类型：
--
作者：
Strozza D;Wilhite DP;Babb TG;Bhammar DM
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 assessment of EFL in children with and without obesity. Forty children (10.7±1.0 years; 27 obese; 15 with EFL) completed pulmonary function tests and incremental exercise tests. Inspiratory capacity maneuvers were performed during the incremental exercise test for 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 MEFV loops. MEFV loops were plotted with volume measured at the lung using plethysmography (MEFVp), volume measured at the mouth using spirometry concurrent with measurements in the plethysmograph (MEFVm) as well as from spirometry before (MEFVpre) and after (MEFVpost) the incremental exercise test. Only the MEFVp loops were corrected for thoracic gas compression. 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 (p<0.001), with no differences between children with and without obesity (p=0.833). The difference in EFL estimation using MEFVpre (37±30%VT) and MEFVpost (31±26%VT) did not reach statistical significance (p=0.346). Not correcting the MEFV loops for thoracic gas compression leads to overdiagnosis and overestimation of EFL. Since most commercially available metabolic measurement systems do not correct for thoracic gas compression during spirometry, there may be significant overdiagnosis of expiratory flow limitation in cardiopulmonary exercise testing. Therefore, clinicians must exercise caution while interpreting expiratory flow limitation when the MEFV loop is derived through spirometry.
