School of Human Kinetics, University of British Columbia, Vancouver, British Columbia, Canada.
Respir Physiol Neurobiol. 2010 Mar 31;170(3):279-86. doi: 10.1016/j.resp.2010.01.017. Epub 2010 Feb 4.
Expiratory flow limitation (EFL) during exercise may be overestimated or falsely detected when superimposing tidal breaths within a pre-exercise maximal expiratory flow volume (MEFV) curve due to thoracic gas compression (TGC) and bronchodilation. Accordingly, the purpose of this study was to determine the effects of TGC and bronchodilation on the assessment of EFL in 35 healthy subjects. A pre-exercise forced vital capacity (FVC) maneuver was performed that did not account for TGC (MEFV(pre)). Subjects then performed graded expirations from total lung capacity to residual volume at different efforts to account for TGC (MEFV(pre-TGC)). Post-exercise FVC (MEFV(post)) and post-exercise graded expirations (MEFV(post-TGC)) were performed to account for bronchodilation and TGC. EFL occurred in 29 subjects when using MEFV(pre). The magnitude of EFL in these subjects was 47+/-23% which was significantly higher than MEFV(pre-TGC) (28+/-28%), MEFV(post) (24+/-27%) and MEFV(post-TGC) (19+/-24%) (P<0.00001). Using the traditional MEFV(pre) curve overestimates and falsely detects EFL since it does not account for TGC and bronchodilation.
运动时呼气流量限制（EFL）可能会因胸内气体压缩（TGC）和支气管扩张而在运动前最大呼气流量容积（MEFV）曲线中叠加潮气呼吸时被高估或错误检测。因此，本研究旨在确定 TGC 和支气管扩张对 35 名健康受试者 EFL 评估的影响。进行了运动前用力肺活量（FVC）操作，但不考虑 TGC（MEFV（pre））。然后，受试者从肺总量到不同努力的残气量进行分级呼气，以考虑 TGC（MEFV（pre-TGC））。进行运动后 FVC（MEFV（post））和运动后分级呼气（MEFV（post-TGC））以考虑支气管扩张和 TGC。当使用 MEFV（pre）时，29 名受试者发生 EFL。这些受试者的 EFL 程度为 47+/-23%，明显高于 MEFV（pre-TGC）（28+/-28%）、MEFV（post）（24+/-27%）和 MEFV（post-TGC）（19+/-24%）（P<0.00001）。由于不考虑 TGC 和支气管扩张，使用传统的 MEFV（pre）曲线会高估和错误检测 EFL。
