The Study Of The Small Airway Function Before And After Bronchial Dilation Test

Objective.The bronchial asthma and chronic obstructive pulmonary disease are the most common diseases in the world.The feature of those diseases is airway obstruction.We study the changes of the lung function about the bronchial asthma and COPD after bronchial dilation test and describe the regularity of the dilatation of the small airway.We also explore the difference and the correlation between the big airway and the small airway in order to identify the two diseases.Methods:We chose 82 patients with asthma and 88 patients with COPD and 41 patients with COPD but the bronchial dilation test is positive.We record the numbers of the FVC,FEV₁,PEF,MEF50%,MEF25%,MMEF before and after the bronchial dilation with the salbutamol.Throgh those numbers,we compare the changes between the small airway and the big airway.We also compare the sensitivity of the positive rate about the small airway function.Results:The small airway lung function and the big airway lung function improved after the bronchial dilation test in the patients with asthma COPD and COPD but the bronchial dilation test is positive(P＜0.01).The lung function of the patients with asthma was better than the patients with the COPD(P＜0.01).The variance rate in FEV₁,MEF50%,MEF25%,MMEF are 22.22%±1.48%,31.53%±3.28%,28.11%±4.18%,151.27%±46.52%.There are statistical significance between those numbers(F=7.031,P＜0.01).The change of small airway of the patients with asthma was high than that before the test(P＜0.01).There was no difference in the variance rate between the test before and the test after in the other two groups(P＞0.05).In the patients with asthma the positive rate of FEV₁,MEF50%,MEF25%,MMEF was 60.98%,75.61%,58.54%,76.83%.The positive rate ofMMEF, MEF50%was more sensitive than the rate of FEV₁(x²=10.352,P=0.016)and correlate with the Severity of the asthma.The more severe the asthma is,the more sensitive the positive rate of the lung function of the small airway is(P＜0.01).The variance rate in MEF50%correlates with the one in FEV₁ in the patients with asthma COPD and COPD but the bronchial dilation test is positive(P＜0.01).The variance rate in MMEF does not correlates with the one in FEV₁ in the patients with asthma COPD and COPD but the bronchial dilation test is positive(P＞0.05).Conclusions:The big and the small airway are all dilated in the patients with asthma,but the dilatation of the small airway is more than the big airway's.In the same time,the positive rate of the small airway lung function is more sensitive than the big airway's.The big and the small airway are all dilated in the patients with COPD.The dilatation of the small airway is no difference with the big airway's.And the positive rate is low in the patients with COPD.The regular about the small airway is convenient to identify asthma and COPD.