A Study On The Application Of Exhaled Nitric Oxide Combined With Small Airway Lung Function In Asthmatic Children

Objective:By analyzing the results of fractional exhaled nitric oxide and small airway pulmonary function in children with asthma,and to explore the value of fractional exhaled nitric oxide,small airway function and their combined detection,so as to provide a basis for the diagnosis and differential diagnosis of childhood asthma.Methods:A total of 88 children with chronic cough admitted to the Department of Pediatrics,the First Hospital of Shanxi Medical University from September 2020 to September 2021 were retrospectively analyzed.They were divided into asthma group（50 cases）and non-asthma group（38 cases）.General data（gender,age,height,weight）,pulmonary function indicators(FVC,FEV₁,FEV₁/FVC,PEF,MMEF_25-75,MEF₅₀)and eNO measurements results（FeNO,CaNO）of the two groups were collected.The differences in general data and various indicators between the two groups were statistically analyzed,as well as the correlation between FeNO,CaNO,and pulmonary function indicators.ROC curves were also plotted to evaluate the diagnostic value of FeNO,CaNO,MMEF_25-75,MEF₅₀,and the combined use of CaNO with MMEF_25-75 and MEF₅₀ for asthma.Results:1.The pulmonary function indicators FVC,FEV₁,FEV₁/FVC,PEF,MMEF_25-75,and MEF₅₀ in the asthma group were lower than those in the non-asthma group,with statistically significant differences（P（27）0.05）.Additionally,the FeNO and CaNO levels in the asthma group were higher than those in the non-asthma group,also with statistically significant differences（P（27）0.05）.2.FeNO showed negative correlations with FVC（r=-0.239,P=0.025）,FEV₁（r=-0.356,P=0.001）,FEV₁/FVC（r=-0.478,P（27）0.001）,PEF（r=-0.267,P=0.012）,MMEF_25-75（r=-0.387,P（27）0.001）,and MEF₅₀（r=-0.379,P（27）0.001）.Similarly,CaNO exhibited negative correlations with FEV₁/FVC（r=-0.278,P=0.009）,MMEF_25-75（r=-0.222,P=0.037）,and MEF₅₀（r=-0.221,P=0.038）.However,there was no correlation between CaNO and FVC or FEV₁（P（29）0.05）.3.The area under the ROC curve of MMEF_25-75,MEF₅₀,FeNO and CaNO for the diagnosis of asthma was 0.922,0.896,0.706 and 0.645,respectively.The optimal cut-off values at this point were 66.665,70.690,17.50 ppb,and 19.25 ppb,with sensitivities of86.8%,81.6%,78.9%,and 81.6%,and specificities of 90.0%,88.0%,56.0%,and 50.0%,respectively.4.The area under the ROC curve of CaNO combined with MMEF_25-75 in the diagnosis of asthma was 0.927,with a sensitivity of 81.6%and specificity of 92.0%.The area under the ROC curve of CaNO and MEF₅₀ combined diagnosis of asthma was 0.905,with a sensitivity of 81.6%and specificity of 86.0%.The area under the ROC curve of CaNO,MMEF_25-75 and MEF₅₀ combined diagnosis of asthma was 0.926,with a sensitivity of 89.5%and specificity of 88.0%.Conclusions:1.In the asthma group,FeNO and CaNO were negatively correlated with MMEF_25-75and MEF₅₀.2.CaNO,MMEF_25-75,and MEF₅₀ are valuable diagnostic tools for children asthma.3.CaNO combined with the small airway function parameters MMEF_25-75 and MEF₅₀was valuable in the diagnosis of asthma and superior to the single parameter included.