A Comparative Study Of Lung Volume Response With Airflow Response To Bronchodilator In Patients With Chronic Obstructive Pulmonary Disease

Objective: For further understanding of the important of pulmonary function test in the diagnosis of chronic obstructive pulmonary disease(COPD) and to explore the difference between lung volume and airflow response in chronic obstructive pulmonary disease.Methods: 255 patients who were diagnosed with COPD, were selected from 1st January 2009 to 5th January 2011. The patients were evaluated for pulmonary function test and the bronchodilation test. The patients selected, were from outpatient department and hospitalized patients as well. The change,the rate of change and the rage of positive reversibility of FEV1 and FVC 15 minutes after inhalation of salbutamol at a dose of 400μg via spacer were measured and results were compared. The pulmonary function test of the 255 patients was obtained and the data was analyzed by using SPSS 17.0 statistical software package.Descriptive analysis were calculated with mean±SD. Before and after bronchial dilation test,analyzing and comparing FEV1and FVC by paired t test . After bronchial dilation test, the change of FEV1 and FVC was compared and analysed with independent t test and correction analysis. The comparation of pulmonary function indexs of different groups were measured with analysis of variance. Both the rate of positive reversibility and the rate of improvement were compared by chi-square test.Results: Post-bronchodilator FEV1 increased 133mL with a 13.18% improvement on average compared with baseline. Post-bronchodilator FVC increased 336mL and improved by 19.88% on average. The rate of positive reversibility in FEV1 and FVC was 29%(74/255) and 60%(152/255), respectively. The rate of improvement in FEV1 and FVC was 52%(132/255) and 73%(185/255). In the periods of chronic obstructive pulmonary disease including mild airflow limitation, moderate airflow limitation, severe airflow limitation and very severe airflow, both the rate of positive and the rate of improvement in FVC changed significant than those in FEV1.Conclusion: Although the improvement of FEV1 and FVC both increased after bronchial dilation test, the improvement of lung volume is more significant and more important than airflow response in patients with COPD, particular in the early period. FVC should be an important index, which is superior to FEV1 in COPD after bronchial dilation test.