A Study On Respiratory Impedence In Chronic Obstructive Pulmonary Disease And Asthma

Objective To investigate applicational value of respiratory impedence measured by impulse oscillometry system(IOS) in the patients with chronic obstructive pulmonary disease and in the patients with asthma.Methods Lung function test in patients with 276 COPD and 88 asthma and 45 healthy persons were measured by routine method and IOS.Lung ventilation function, basal lung capacity, diffusion capacity and respiratory impedence in patients with different stages of COPD, asthma and control group were performed, and the comparison among the different groups were made. The correlation between lung ventilation function and airway resistance were analyed.Results 1.The ventilatory function:1.1 Compared with the healthy controls, COPD and asthma patients had a decrease in FEV1.0, FEV1.0%pred, FEV1.0/FVC, FEF50%, FEF50o%%pred, MVV, MVV%pred(P<0.05或P<0.01).1.2 FEV1.0, FEV1.0/FVC, FEF50%, FEF50%%pred in COPD patients were all significantly lower than that in asthma patients(P<0.05 or P<0.01).1.3 Increment value of FEV1.0 and change rate of FEV1.0 of bronchial dilation test in COPD patients were all significantly lower than that in asthma patients(P all<0.01).1.4 There were significant decrease in FEV1.0, FEV1.0%pred, FEV1.0/FVC, MVV, MVV%pred, FEF50%, FEF50%%pred with COPD deteriorated (P all<0.01).2.The basal lung capacity:2.1 Compared with the healthy controls, COPD patients had a significant increase in RV (P<0.01),COPD and asthma patients had a significant increase in TLC, RV/TLC(P<0.05 or P<0.01).2.2 RV, TLC, RV/TLC in COPD patients were all significantly higher than that in asthma patients(P<0.05 or P<0.01).2.3 RV in moderate and serious COPD patients was significantly higher than that in mild COPD patients (P<0.05).There was a increase in TLC with COPD deteriorated(P<0.05 or P<0.01).RV/TLC in serious COPD patients was significantly higher than that in mild and moderate COPD patients (P all <0.01).3.The diffusion capacity:3.1 Compared with the healthy controls, COPD and asthma patients had a significant decrease in diffusion lung capacity for carbon monoxide (DLco) (P<0.05 or P<0.01).3.2 DLco in COPD patients were all significantly lower than that in asthma patients(P<0.05).3.3 There was gradual decrease in DLco with COPD deteriorated (P<0.05 or P<0.01).4.The IOS:4.1 Z5in COPD patients (0.57±0.26) kPa·L-1·s-1 was significantly higher than that in the healthy controls (0.43±0.24) kPa·L-1·s-1(P<0.01).R5 in COPD patients (0.52±0.24) kPa·L-1·s-1 was higher than that in the healthy controls (0.41±0.23)kPa·L-1·s-1 (P<0.05).R20 in asthma patients (0.33±0.10) kPa·L-1·s-1 was higher than that in the healthy controls (0.29±0.09) kPa·L-1·s-1(P<0.05). R5-R20 in COPD patients (0.21±0.17) kPa·L-1·s-1 and asthma patients (0.15±0.15) kPa·L-1·s-1 was higher than that in the healthy controls (0.12±0.16) kPa·L-1·s-1 (P<0.05 or P<0.01). Rc in COPD patients (0.25±0.10) kPa·L-1·s-1 and asthma patients (0.29±0.08) kPa·L-1·s-1 was higher than that in the healthy controls (0.15±0.07)kPa·L-1·s-1 (P all<0.05). Rp in COPD patients (0.62±0.37) kPa·L-1·s-1 and asthma patients (0.45±0.14) kPa·L-1·s-1 was higher than that in the healthy controls (0.24±0.09) kPa·L-1·s-1 (P all<0.01). Fres in COPD patients (23.16±9.01) Hz and asthma patients (19.76±6.25) Hz was higher than that in the healthy controls (14.50±6.69) Hz (P all<0.01). Changes of X5 in COPD patients (-0.22±0.14)kPa·L-1·s-1 and asthma patients (-0.16±0.10) kPa·L-1·s-1 was more negative than that in the healthy controls (-0.12±0.07) kPa·L-1·s-1 (P<0.05 or P<0.01).4.2 R5-R20, Rp, Fres in COPD patients [(0.21±0.17)kPa·L-1·s-1,(0.62±0.37)kPa·L-1·s-1,(23.16±9.01)Hz] were higher than that in asthma patients [(0.15±0.15)kPa·L-1·s-1,(0.45±0.14)kPa·L-1·s-1,(19.76±6.25) Hz].Changes of X5 in COPD patients (-0.22±0.14)kPa·L-1·s-1 was more negative than that in asthma patients(-0.16±0.10)kPa·L-1·s-1 (P<0.05).4.3 Z5,R5,R5-R20, Rc, Rp,Fres in moderate and serious COPD patients [(0.56±0.27,0.67±0.22)kPa·L-1·s-1,(0.52±0.25,0.59±0.20)kPa·L-1·s-1,(0.20±0.17,0.28±0.14)kPa·L-1·s-1, (0.24±0.06,0.29±0.05) kPa·L-1·s-1,(0.61±0.34,0.65±0.07) (22.53±7.96,27.60±9.77) Hz] were significantly higher than that in mild COPD patients [(0.45±0.22)kPa·L-1·s-1,(0.42±0.21)kPa·L-1·s-1,(0.13±0.14)kPa·L-1·s-1,(0.18±0.04) kPa·L-1·s-1,(0.52±0.21)kPa·L-1·s-1,(18.25±7.04) Hz](P<0.05 or P<0.01).Changes of X5 in moderate and serious COPD patients (-0.21±0.13,-0.30黑日日0.15) kPa·L-1·s-1 was more negative than that in mild COPD patients (-0.15±0.09)kPa·L-1·s-1(P all<0.01).There was not significantly increase in R20 with COPD deteriorated(P>0.05).5.Correlation analysis:5.1 The correlation analysis indicated that lung ventilation function of FEV1.0/FVC, FEV1.0%pred, MVV, MVV%pred, FEF50%, FEF50%%pred had a negative correlation with airway resistance of Z5, R5,R5-R20 and a positive correlation with X5 in COPD patients(P<0.05 or P<0.01). FEV1.0/FVC,FEV1.0%pred of COPD patients had not statistically correlation with R20 (P all>0.05).5.2 FEV1.0, FEV1.0/FVC, MVV,MVV%pred,FEF50%, FEF50%%pred of asthma patients had a negative correlation with airway resistance of Z5,R5,R5-R20 and a positive correlation with X5 in asthma patients (P all<0.01). FEV1.0, FEF50%, FEF50%%pred of asthma patients had a negative correlation with Fres(P all<0.01).FEV1.0/FVC, MVV, MVV%pred had not statistically correlation with Fres (P all>0.05).Conclusion Lung function test was the key method for diagnosing COPD and asthma. IOS can reflect changes of airway mechanics in patients with COPD and asthma. IOS technique plays an important role in diagnosis of COPD and in evaluation progression of COPD, and is complementary to lung function test in COPD patients. By analysis of changes of airway mechanics, IOS can detect differences and similarities of airway mechanics in patients with COPD and asthma. So IOS has important clinical application value.