Objective To investigate the changes of small airway function and diffusing capacity in patients with mild asthma before and after bronchial provocation test (BPT).Methods BPT was performed in suspected asthma patients with chief complaints of paroxysmal wheeze,chest tightness and cough，but with normal chest X-ray and baseline pulmonary function.BPT positive group was regarded as asthma group，while BPT negative group as control group.Lung volume，ventilatory function and diffusing capacity were measured before and after BPT and compared between the asthma and control groups.Results （A）No statistical differences were found in FEV1%，FEV1/FVC，FVC%，VC%，TLC%，FRC%，RV%，RV/TLC between the asthma and control groups before BPT.FEV1/FVC and FVC% were significantly decreased (all Plt;0.01)，while FRC% (Plt;0.05)，RV% (Plt;0.01) and RV/TLC (Plt;0.01) increased significantly in the asthma group after BPT compared with the control group.The decline rate of FEV1/FVC and FVC% and the increase rate of TLC%，RV%，RV/TLC were significantly higher in the asthma group than those in the control group (all Plt;0.01).（B）Compared with the control group，FEF25%-75% (Plt;0.05)，Vmax75% (Plt;0.01) and Vmax50% (Plt;0.05) were significantly lowered before BPT，while the above parameters and Vmax25% were significantly decreased after BPT in the asthma group (all Plt;0.01).The decline rate of FEF25%-75%，Vmax75%，Vmax50% and Vmax25% was significantly higher in the asthma group than those in the control group (all Plt;0.01).（C）There was no statistical difference in DLCO in both groups before and after BPT.Conclusions Patients with mild asthma had small airways impairment before BCT which further declined after BPT.However,no impairment of diffusion capacity was found before or after BPT.
ObjectiveTo assess the lung capacity and diffusing capacity in patients with chronic obstructive pulmonary disease (COPD) at different stages. MethodsPatients who were diagnosed with COPD between January and March 2015 were recruited in the study. The data of clinical characteristics and spirometry test (the forced expiratory volume in the first second, FEV1) were collected. Total lung capacity (TLC) and residual volume (RV) were determined by body plethysmography and helium dilution method, and single breath diffusing capacity for carbon monoxide (DLCO) was also measured. Lung capacity and the deviations between two methods, and DLCO%pred were compared among the COPD patients at different stages. The correlation of spirometry with lung capacity and DLCO%pred were analyzed. ResultsA total of 170 patients with COPD were enrolled. With the severity of COPD, TLC%pred, RV%pred, RV/TLC and the deviations of the ones between two methods increased significantly, but DLCO%pred reduced significantly. FEV1%pred were negatively correlated with the deviations of lung capacity between two methods, and positively correlated with DLCO%pred. ConclusionsCompared with helium dilution method, the body plethysmography is more accurate for evaluating the lung capacity of COPD. With the severity of airflow limitation, the diffusing capacity of COPD decreases gradually.
ObjectiveTo assess the lung capacity and diffusing capacity in patients with chronic persistent asthma with different severities. MethodsPatients diagnosed with chronic persistent asthma in West China Hospital between January 2014 and April 2015 were recruited in the study.The data of clinical characteristics were collected.The forced expiratory volume in the first second (FEV1) was determined by spirometry test.Total lung capacity (TLC) and residual volume (RV) were determined by body plethysmography and helium dilution method.Single breath diffusing capacity for carbon monoxide (DLCO) was also measured.Lung capacity and the deviations between two methods, and DLCO%pred were compared among different patient groups with mild, moderate and severe asthmas.The correlation between spirometry with lung capacity and DLCO%pred were analyzed. ResultsA total of 93 patients with chronic persistent asthma were enrolled.With the severity of asthma, TLC%pred, RV%pred, RV/TLC and the deviations of the ones between two methods increased significantly, but DLCO%pred reduced slightly.FEV1%pred were negatively correlative with the deviations of lung capacity between two methods, and positively correlative with DLCO%pred. ConclusionsCompared with helium dilution method, the body plethysmography is more accurate for evaluating the lung capacity of chronic persistent asthma.With the severity of airflow limitation, the diffusing capacity of asthma is decreasing gradually, but still within the normal limits.
ObjectiveTo verify the existing domestic and foreign formulas of normal predictive value indicator for adult pulmonary diffusion capacity’s applicability at current stage in Kunming.MethodsBased on the pulmonary diffusion capacity parameters determination of diffusion capacity for carbon monoxide of the lung (DLCO) collected from one-breath breathing test completed by 680 adults with healthy lung function and without any disease which may cause pulmonary diffusion dysfunctions in Kunming, the regression equation of adult DLCO normal predicted value in Kunming was initially established; the fitting degree of DLCO predicted value and measured value was verified; and the correlation between European adults (instrument-inherent ECCS93) and the normal predicted values of adult DLCO in Shanghai, Chongqing and Lhasa were calculated and contrasted.ResultsThe regression equation of adult DLCO normal predicted value in Kunming was initially established: for male, 0.483+0.063×height (cm)+0.041×weight (kg)–0.071×age (years); for female, 1.679+0.055×height (cm)+0.018×weight (kg)–0.060×age (years). The data collected from the one-breath breathing test were similar to the predicted values obtained from the normal adult male and female DLCO prediction formulas in Kunming, the difference was not statistically significant (tM=–0.167, tF=–0.436, both P>0.05), suggesting that the formula for predicting the value established in this study was valid and well fitted. The predicted value of adult DLCO in Kunming area was statistically significant compared with the adult DLCO estimates of European adults and Lhasa, Chongqing and Shanghai in China (FM=713.4, FF=1 442.2, both P<0.001). Lhasa had the highest value; Kunming was the second highest; instrument-inherent European area and Chongqing came to third and fourth; and Shanghai had the lowest predicated adult DLCO value (all P<0.001).ConclusionThe current predictive formulas for adult pulmonary diffusion capacity indicators in China and worldwide are not suitable for the populations in Kunming.