Correlational Study Of Impulse Oscillometry Combined With CaNO In Common Small Airway Dysfunction Diseases

Objective:1.This study aims to analyze the characteristics of lung function and airway inflammation in patients with several common small airway dysfunction diseases.2.To analyze the diagnostic efficacy of impulse oscillometry and CaNO in small airway dysfunction（SAD）,and to explore the sensitive indexes for evaluating small airway function.Methods:A total of 247 patients with newly diagnosis or stable small airway dysfunction examined in the Lung function Room of the first Hospital of Shanxi Medical University from April 2021 to October 2022 were collected,and the pulmonary ventilation dysfunction grade（ATS/CRS 2005/2019 standard five-point method）was mild to moderate.There are two grouping methods:first,according to medical history and pulmonary function test,all of the patients are divided into COPD group（group 1）,asthma group is divided into cough variant asthma group（group 2）and classic asthma group（group 3）,ACO group（group 4）,simple SAD group（group 5）and Lung function test normal group（group 6）.The general data,spirometer examination,carbon monoxide diffusion function,impulse oscillation and exhaled nitric oxide were recorded,and the characteristics of pulmonary function and airway inflammation in each group were analyzed.The second is divided into group A and group B according to spirometer to examine whether there is small airway dysfunction.The study aims to analyze the diagnostic efficacy of impulse oscillation and CaNO in small airway dysfunction（SAD）and to explore sensitive indexes for evaluating small airway function.。Results:1.Compared with the general data among the six groups,there were statistically significant differences in age,sex and smoking between group 1 and the other groups（P<0.05）.And the age of group 2 was lower than that of group 1,group 4 and group 3,the difference was statistically significant（P<0.05）.2.There was statistically significant difference in some indexes among the six groups（P<0.05）,and the six groups were compared in pairs.Spirometer:FVC%in group1 was lower than that in group 2,group 3,group 6.And FVC%in group 5 was lower than group 2,group 3.MMEF%,MEF_50%%,MEF_25%%and FEV₁%in group 6 were highest,while those in group 1 were lower than those in other groups except group 4.FEV₁/FVC and FEV_1/FEV₆was highest in group 6,group 1 and group 4 were lower than other groups.Carbon monoxide diffusion function:RV%in group 1,group 3 and group 4was higher than that in group 6,and that in group 4 was higher than that in group 5.There was no statistically significant difference in D_LCO%,ERV%,RV/TLC,FRC%and FRC/TLC among the six groups（P>0.05）.Impulse oscillometry:Fres,Z5,Z5%,R5,R5%and AX in group 6 were lowest,and Fres of group 1 was higher than that of group 2and group 3.Z5 and AX of group 1 was higher than that of group 3.And R20 in group 6was lower than that of other groups except group 1,while that of group 2 and group 5was higher than group 1.R20%in group 6 was lower than that of other groups except group 4.Delta R5-R20 of group 1 was higher than that of group 2,group 3 and group 6.All of the six group,group 6 had the highest X5,and X5 of group 1 was lower than that of group 3.There was no statistical difference in Fe NO and CaNO among the six groups（P>0.05）.3.The correlation analysis of some indexes among the six groups showed that FEV₁/FEV₆,ERV%and X5 were positively correlated with MMEF%,MEF_50%%and MEF_25%%（r>0,P<0.05）,while RV%and R20 show relevant relations with MMEF%,MEF_50%%and MEF_25%%（r<0,P<0.05）.RV/TLC,Fres,Z5,Z5%,R5,R5%,R20,Delta R5-R20 and AX were negatively correlated with FEV₁/FEV₆,MMEF%,MEF_50%%and MEF_25%%（r<0,P<0.05）.Fe NO was negative correlation with FEV₁/FVC,MMEF%and MEF_50%%（r<0,P<0.05）.CaNO was negatively related to FEV₁/FVC,MEF_50%%and MEF_25%%（r<0,P<0.05）.4.There were significant differences in impulse oscillation indexes（Fres,AX,Z5,X5）between group A and group B（P<0.05）,Fres,AX and Z5 in group A were higher than those in group B,but there was no significant difference in CaNO between group A and group B（P>0.05）.5.The area under ROC curve of impulse oscillation indexes（Fres,AX,Z5）combined with CaNO is 0.731（95%CI:0.666～0.795）,and the area under AX curve is0.723（95%CI:0.657～0.788）.Conclusion:1.Small airway dysfunction exists in patients with COPD,asthma and ACO,and the involvement of small airway is more serious in patients with COPD.2.There was correlation between impulse oscillation index,CaNO and small airway index examined by spirometer.3.Imulse oscillation indexes（AX,Z5,Fres）has certain clinical value in the diagnosis of small airway dysfunction,and the diagnostic efficacy of AX is slightly better than others,and the best cut-off value is 4.380cm H₂O/L.