Effect of bronchodilation on expiratory flow limitation and resting lung mechanics in COPD

摘要: Bronchodilator drugs produce variable improvements in forced expiratory volume 1 s (FEV1), but larger changes end-expiratory lung (EELV) chronic obstructive pulmonary disease (COPD), which were suggested to be related the presence of flow limitation (EFL) at rest. We tested this concept 42 COPD patients (FEV1 42.3±13.8% predicted) during spontaneous breathing before and after 5 mg nebulised salbutamol. EFL was detected by within-breath respiratory system reactance measured a multifrequency oscillation method, while EELV assessed inspiratory capacity (IC). Bronchodilation (BD) increased IC (from 1.8±0.5 2.1±0.6 L, p<0.001) reduced inspiration resistance ( R insp) 5 Hz 5.1±1.6 4.2±1.5 cmH2O·s·L−1, p<0.001). insp identified BD responders with discriminative power 80.1%. In total, 20 flow-limited BD. They showed worse spirometry higher residual volume, significant seen all irrespective limitation. Changes confined patients, as changes. degree heterogeneity system, change best values. BD has complex effects on mechanics COPD, affects both response some variables treatment. However, are consistently seen, rest.