Correlation Between Fractional Exhaled Nitric Oxide Levels And Different Airway Inflammation Phenotypes In Asthmatic Patients

Objective:To study the level of fractional exhaled nitric oxide(FeNO)in asthma patients and its correlation with different airway inflammatory phenotypes.Methods:From April 2017 to June 2018,102 patients with acute asthma in the Department of Respiratory Medicine and hospitalization in Cangzhou Central Hospital as Asthma Groupwere selected as the case group,and divided into eosinophilic asthma group(EA);neutrophilic asthma group(NA);mixedgranulocytic asthma group(MA);paucigranulocytic asthm group(PA)four groups according to the classification of induced sputum cytology.35healthy outpatients in the same period were selected as the control group.To explore the diagnostic value of fractional exhaled nitric oxide level in asthma by drawing ROC curve,and to compare the different levels of fractional exhaled nitric oxide in four groups of asthma patients and healthy people.To further study the value of fractional exhaled nitric oxide in asthma with different airway inflammation.Results:1.The fractional exhaled nitric oxide level in eosinophilic asthma was(91.79±53.52)ppb.The fractional exhaled nitric oxide level in mixedgranulocyticl asthma was(76.58±45.88)ppb.The fractional exhaled nitric oxide level of neutrophilic asthma was(41.43±19.08)ppb.The fractional exhaled nitric oxide level of paucigranulocytic asthma was(35.20±17.88)ppb.The levels of fractional exhaled nitric oxide in eosinophilic granulocytic asthma and mixedgranulocyticl asthma were significantly higher than those in normal subjects(25.71±15.04)ppb,the difference is statistically significant(P<0.05).There was no significant difference in fractional exhaled nitric oxide level between neutrophilic asthma paucigranulocytic asthmand normal group(P>0.05).There was no significant difference between eosinophilic asthma and mixedgranulocytic asthma in fractional exhaled nitric oxide level(P>0.05).There was no significant difference in the level of fractional exhaled nitric oxide between neutrophilic asthma and paucigranulocytic asthm(P>0.05).The fractional exhaled nitric oxide levels in eosinophilic asthma and mixedgranulocytic asthma were higher than those in neutrophilic asthma and paucigranulocytic asthm(P<0.05).2.The serum eosinophil level in eosinophilic asthma was(0.41±0.30)×10~9/L,and that in mixedgranulocytic asthma was(0.29±0.21)×10~9/L,there is a statistically significant difference between the two,(P<0.05).The level of eosinophils in serum of eosinophilic asthma was higher than that of paucigranulocytic asthm.The serum eosinophil level was(0.11±0.09)×1010~9/L in neutrophilic asthma and(0.11±0.06)×10~9/L in paucigranulocytic asthm,there was no statistical difference between them(P>0.05).The levels of eosinophils in serum of eosinophilic asthma and mixedgranulocytic asthma were higher than those of paucigranulocytic asthm and neutrophilic asthma,and there was significant difference between the two groups(P<0.05).3.The fractional exhaled nitric oxide level in asthma patients was(65.08±45.82)ppb higher than that in normal subjects(25.71±15.04)ppb,the difference was statistically significant(P<0.05).The optimal threshold for the diagnosis of asthma was 32.5 ppb,and specificity was 0.800,sensitivity was 0.765,the area under ROC curve was 0.843,and the confidence interval was(0.773~0.914).The level of fractional exhaled nitric oxide was not correlated with age,body weight,pulmonary function,macrophage,lymphocyte in sputum and serum IgE(P>0.05).The levels of fractional exhaled nitric oxide were correlated with height(r=0.211,P<0.05),sputum neutrophils(r=0.269,P<0.05),and eosinophils in sputum(r=0.531,P<0.05).Conclusion:1.The fractional exhaled nitric oxide levels contribute to the diagnosis of asthma,and the optimal threshold of 32.5 ppb.The levels of fractional exhaled nitric oxide in asthma with different airway inflammatory phenotypes were different.The level of FeNO in patients with eosinophilic asthma was higher than that in patients with mixedgranulocytic asthma.The fractional exhaled nitric oxide levels in eosinophilic asthma and mixedgranulocytic asthma were higher than those in paucigranulocytic asthm and neutrophilic asthma.2.The levels of eosinophils in blood of asthma patients with different airway inflammatory phenotypes were different.Eosinophilic asthma was the highest,mixedgranulocytic asthma was the second,and neutrophilic asthma and paucigranulocytic asthm were the last.3.The level of fractional exhaled nitric oxide(65.08±45.82)ppb,was positively correlated with eosinophils in sputum and negatively correlated with neutrophils in sputum in asthmatic patients.It was not related to pulmonary function,macrophages and lymphocytes in sputum,and so on.