Correlation Between FeNO And Peripheral Blood Eosinophils In Patients With Acute Exacerbation Of COPD

Objective:To investigate the relationship between exhaled nitric oxide（Fe NO）levels and peripheral blood eosinophils（EOS count>300/μl,≤300/μl）,age,gender,lung function,and so on in patients with acute exacerbation chronic obstructive pulmonary disease（AECOPD）.To investigate whether Fe NO value can also be used as a biological indicator to distinguish AECOPD patients with bleeding EOS counts≤300/μl and>300/μl,and guide doctors to evaluate the benefits of increasing ICS treatment to prevent future acute exacerbations.Methods:A total of 169 AECOPD patients admitted to the Department of Respiratory Medicine of Dalian Central Hospital from January 2017 to October 2019 were selected.Among them,46 patients had a blood EOS count>300/μl and 123 patients had a blood EOS count≤300/μl.The basic patient information（age,gender,smoking history,height,weight,BMI）was collected,the Fe NO value of the patient was recorded by using a Naculum nitric oxide detector（SV-Eno-03）,the patient’s lung function level（FEV₁%pred,FEV₁/FVC）was recorded by GHESTAC-8800 lung function meter,and the patient’s peripheral blood eosinophil count was measured by using a fully automatic blood cell analyzer.Data analysis was performed by using SPSS23 analysis software to study the correlation between Fe NO value and peripheral blood eosinophils,age,height and other variables,and draw the receiver operating（ROC）curve to analyze the predictive value of Fe NO value on blood EOS count>300/μl.The maximum value of the Youden index corresponded to the optimal limit of Fe NO.Results:1.The Fe NO value of 169 patients with AECOPD was 25（14.00,36.00）ppb,there were no significant differences in Fe NO values between the groups of male and female,smoking and no-smoking,different ages,heights,weights,BMI and different lung function levels（P>0.05）;2.Using Fe NO value as the dependent variable,age,gender,smoking history,height,weight,BMI,FEV₁%pred,and FEV₁/FVC as independent variables,the correlation analysis was performed,and the results showed that Fe NO value was not correlated with the above independent variables（P>0.05）;3.Fe NO values were positively correlated with EOS in peripheral blood with counts>300/μl and≤300/μl,but the correlation between Fe NO values and blood EOS with a count>300/μl（r=0.687）was stronger than the correlation with blood EOS with a count≤300/μl（r=0.470）;the EOS count>300/μl group（46 cases）had a Fe NO value of 39.5（33.00,48.25）ppb,and the EOS count≤300/μl group（123 cases）had a Fe NO value of 18（11.00,27.00）ppb,the mean Fe NO in the group>300/μl was higher than the mean Fe NO in the group≤300/μl,the differences between two groups were statistically significant（P<0.0001）;4.The ROC curve analysis showed that the baseline Fe NO prediction value for blood EOS count>300/μl was significant（AUC=0.888）,and the best cut-off point for Fe NO was 29.5ppb（sensitivity 0.848,specificity 0.854）.Conclusion:1.AECOPD patients’Fe NO values are positively correlated with peripheral blood eosinophils（EOS counts>300/μl,≤300/μl）,and can be used as a marker to reflect the eosinophilic inflammation of the airways.2.The Fe NO value can be used as a biological indicator to predict the preventive effect of increasing ICS on the future acute exacerbation of COPD patients on the basis of bronchodilator therapy.3.The results of this study show that there is no correlation between Fe NO value and age,gender,smoking history,height,weight,BMI and lung function（FEV₁%pred,FEV₁/FVC）in AECOPD patients.