Early Intervention Study Of Small Airway Resistance Changes Before And After Airway Responsiveness Test In Asthma-COPD Overlap Patients

Objective:Objective to explore the early intervention value of small airway resistance changes before and after measurement of airway responsiveness in asthma-COPD overlap patient.Methods:Collect our respiratory outpatient and ward.lung function room bronchial provocation test(BPT)was positive in 61 cases of bronchial asthma patients for clinical analysis.According to the results of lung function(small airway indicators:FEF50%,FEF75%,FEF25%-75%)and bronchial provocation test and dilation test,the patients were divided into small airway irreversible group(group A)and small airway reversible group(group B).In group A.at least two values of FEF50%,FEF75%.FEF25%-75%were less than 65%before provocation test,and the small airway resistance did not return to normal after dilation test.In group B,at least two values of FEF50%,FEF75%,FEF25%-75%were more than 65%before provocation test,and the small airway resistance returned to normal after dilation test.The changes of the airway indexes FEV1,FEF75%,FEF50%and FEF25%-75%before and after bronchial provocation test and dilation test were observed.Results:1.There were no significant difference in general data of gender,height,age and weight between the two groups,all P>0.05.2.Comparison of airway function indexes between the two groups before the stimulation:FEV1%pre(t--5.674,P<0.01),FEF50%pre(t--11.090,P<0.01),FEF75%pre(t=-10.005,P<0.01)and FEF25%-75%pre(t=-13.175,P<0.01)in group A were all lower than those in group B,the difference between the two groups was statistically significant(P<0.01),suggesting that the small airway function in group A had been damaged before stimulation.After the stimulation,FEV1%pre,FEF50%pre,FEF75%pre and FEF25%-75%pre in the two groups were significantly decreased compared with those before stimulation(P<0.01),suggesting that there were small airway inflammation and airway hyperresponsiveness in both groups,and the decrease in group B was more significant than group A.3.After inhaled bronchodilator,the function of small airway in group B returned to normal level.and the FEV1%pre,FEF50%pre,FEF75%pre and FEF25%-75%pre in group A were lower than those in group B(t values were-4.379,-13.265,-9.812,-12.729,all P<0.01).It indicates that the incomplete obstruction of small airway in group A continued to exist after dilation test,which was statistically significant compared with group B.4.After inhaling salbutamol broncnodilator.the obstruction of small airway in the two groups was obviously improved,and there was a significant difference in the improvement rate of FEF75%and FEF25%-75%.The improvement rate of FEF75%and FEF25%-75%in group B was significantly higher than that in group A(P<0.05).These results suggest that small airway inflammation,airway narrowing,remodeling and irreversible damage in group A lead to decrease in airway expansibility and sensitivity to dilators.Conclusion:In the course of disease progression of patients with bronchial asthma,there is irreversible impairment of small airway function.The change of small airway resistance before and after the measurement of airway reactivity are benefit to the earlv detection of asthma-COPD overlap.It is helpful to prevent the risk of bronchial asthna developing into irreversible damage of small airway and leading to chronic obstructive pulmonary ventilation dysfunction and to provide intervention strategies for early diagnosis and early treatment of asthma-COPD overlap.