Objective To evaluate the effects of inhaled bronchodilators on respiratory mechanics in moderate and severe chronic obstructive pulmonary disease（COPD） patients during eupnea.Methods Twenty moderate to severe COPD subjects were divided into three groups.Lung function，Borg score，breathing pattern and respiratory mechanics indexes were measured at baseline and 30 min after inhaled placebo，salbutamol 400 μg (or ipratropium 80 μg)，and ipratropium 80 μg (or salbutamol 400 μg) in sequence at interval as specified in different groups.Results In all groups，inhaled bronchodilators improved lung function (FEV1，FVC，IC) (Plt;0.05)，decreased Pdi，Peso，PTPdi，PTPeso and Raw (Plt;0.05，respectively)，in comparison with placebo.The reduction of PTPeso was positively correlated with the reduction of Peso (r=0.713，Plt;0.01）and Raw (r=0.602，Plt;0.01).Borg score decreased after inhaled bronchodilators (Plt;0.05).The reduction of dyspnea was positively correlated with the reduction of inspiratory work of breathing (ΔPTPeso%) (r=0.339，Plt;0.05) and Raw (ΔRaw) (r=0.358，Plt;0.05)，while was not associated with the changes of FEV1，FVC and IC.Conclusions In COPD patients，inhaled bronchodilators can reduce inspiratory work of breathing and airway resistance，the reduction of inspiratory work of breathing contributed to the reduction of airway resistance.Alleviation of dyspnea by inhaled bronchodilators is suggested to be ascribed to reduction of airway resistance and inspiratory work of breathing.
Objective To compare the differences of flow and volume responses in patients with mild to very severe chronic obstructive pulmonary disease（COPD） in bronchodilatation test. Methods The different changes of FEV1 and FVC in 217 patients with mild to very severe COPD（GOLD stage Ⅱ-Ⅳ） after inhaling salbutamol were analyzed retrospectively. Results FEV1 and FVC of the patients with COPD at stage Ⅱ-Ⅳ increased remarkably after inhaling β2 agonist，while there were significant differences between the changes of FEV1 and FVC. Increment of FEV1 and FVC (ΔFEV1 and ΔFVC)，representing flow and volume responses respectively，showed a normal distribution. The majority of patients fell in the range of ΔFEV1 from 0.00 to 0.04，0.05 to 0.09 and 0.10 to 0.14 liter，and ΔFVC from 0.00 to 0.09，0.10 to 0.19 and 0.20 to 0.29 liter. There was significant difference of ΔFEV1 among stage Ⅱ-Ⅳ patients with COPD （Plt;0.01），namely more severe the disease less ΔFEV1 got.In the other hand ΔFVC increased along with the progression of COPD，although no significant difference of ΔFVC among stage Ⅱ-Ⅳ patients with COPD was found. Though different changes of ΔFEV1 and ΔFVC were revealed，there was a positive correlation between ΔFEV1 and ΔFVC in patients at each GOLD stage and the correlation became more insignificant with the progression of COPD. Conclusions There are significant differences between post-bronchodilator flow and volume responses in patients with COPD.Flow response decreases remarkably along with the progression of COPD，whereas volume response increases along with the progression of COPD.
ObjectiveTo explore the difference in clinical characteristics and airway inflammation in COPD patients with different bronchodilator test results. MethodsA total of 237 COPD patients visited between January 2013 and December 2014 were recruited in the study. The ability to complete daily living questionnaire (ADL),modified Medicine Research Council (mMRC) score,6-minute walk distance,pulmonary function,and cell count in induced sputum were measured in the patients. They were divided into a positive group and a negative group according to the response to bronchodilator test and compared. ResultsThere were 58 cases (24.47%) in the positive group,and 179 cases (75.53%) in the negative group. There were no differences in the cumulative amount of smoking[(44.36±17.51) pack-years vs. (50.15±30.51) pack-years],duration of recurrent cough[(14.1±11.1) years vs. (15.5±11.4) years],history of allergic diseases (22.40% vs. 30.80%),or family history of allergic disease (5.17% vs. 2.23%) between two groups. In the positive group,FEV1%pred[(51.04±13.26)% vs. (44.10±14.66)%] and FVC%pred[(73.81±13.60)% vs. (64.33±15.17)%] were better than those of the negative group (both P<0.05). DLCO%pred[(44.66±13.92)% vs. (40.60±17.31)%] and RV/TLC[(51.80±10.57)% vs. (53.16±11.15)%] had no significant differences between two groups. 43.10% of the patients in the positive group and 61.46% in the negative group felt shortness of breath after walking (P<0.05). The positive group scored 22.6±3.8 points in activities of daily living assessment,1.5±0.9 points in mMRC,436.22±102.83 meters in 6-minute walking test,and 2.7±2.1 points in Borg scale score,which were all better than those in the negative group (all P<0.05). There was no significant difference in cell counting in induced sputum between two groups. ConclusionsA part of COPD patients have positive response to bronchodilator,with better lung function,better ADL score,better mMRC score,and farther 6-minute walking distance. It suggests that a positive bronchodilator response might be a clinical phenotype of COPD.