Objective To investigate the changes of pulmonary diffusing capacity and pulmonary capillary blood volume in stable COPD patients with mixed ventilation dysfunction, and explore the possible pathophysiological factors. Methods 159 stable COPD patients with mixed ventilation dysfunction were recruited in the study and 36 normal subjects were recruited as control. The Belgium medisoft box5500 was used to determine the pulmonary ventilation function, lung capacity, and pulmonary diffusing capacity. The measured parameters included forced vital capacity ( FVC) , forced expiratory volume in one second ( FEV1 ) ,maximal voluntary ventilation ( MVV) , vital capacity ( VC) , total lung capacity( TLC) , residual volume ( RV) , minute volume of alveolar ventilation ( VA ) , lung diffusing capacity for carbon monoxide ( DLCO) , pulmonary membrane diffusing capacity for carbon monoxide ( DMCO) , and pulmonary capillary blood volume ( Vc) . The above parameters were compared between the COPD patients and the normal subjects. The relationship was analyzed between DLCO% pred, DMCO% pred, Vc% pred and all the ventilation parameters. Results In stable COPD patients with mixed ventilation dysfunction, all parameters of pulmonary ventilation function, lung capacity, and pulmonary diffusing capacity were significantly different from the normal subjects ( Plt;0. 05 or Plt;0.01) . FVC, VC, VA, and DMCO of the COPD patients were about 66% of the calculated value or more. The average TLC%pred was a little higher than the normal. FEV1 , MVV, DLCO and Vc were abnormally lower which were between 36% ～44% . The average RV%pred was 188% of the predicted value. Obvious correlation could be detected between DLCO% pred, DMCO% pred, Vc%pred and FEV1%pred, FEV1/FVC, TLC% pred, RV%pred, RV/TLC and VA% pred etc.Conclusions In COPD patients with mixed ventilation dysfunction, the pulmonary blood capillary is damaged seriously which lead to a significant decrease of the capacity of pulmonary blood capillary, as well as seriously air distribution disturbance and ventilation/bloodstream mismatch. The Vc decline may develope before the impairment of pulmonary diffusing capacity which may contribute to the damaged of DLCO and DMCO.
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.