| Objective:The study of fractional exhaled nitric oxide(Fe NO) had an about 20 years history. Nitric oxide(NO) was found in human and animals’ expiration in 1991, and it was higher in asthmatic people. It was reported that Fe NO could apply to diagnose, treat and manage asthma according to American Thoracic Society(ATS)’s guideline, 2011. To analyze the application of Fe NO values in 1-4 years asthmatic children and values distribution in these children. Discuss the cut-off value of Fe NO between asthmatic children and control group by receiver operating characteristic(ROC) curve. It was reported that there was a positive correlation between Fe NO and the degree of eosinophilis in blood, sputum, bronchoalveolar lavage specimens, or bronchial mucosa. It still had controversy in the correlation among Fe NO and lung function parameters. The article aimed to analyze the relationship among Fe NO and lung function parameters and eosinophilia counts(EOS). Evaluate the changes of Fe NO values with high blood leukocytes. Summarize relevant experience in order to enrich clinical knowledge.Methods:A total of 138 asthmatic children aged 1-4 years with average age(3.16±0.96) years(82 boys and 56 girls) attending the Department of Respiratory, Children’s Hospital of Hebei Province during May to October, 2014, were recruited, with 60 healthy children(the same age) as control group. After getting parents’ informed consent, Fe NO were measured for all as well as lung function and peripheral blood routine. The asthmatic children were divided into two groups, acute stage group(n=63) and remission stage group(n=75). Collect Fe NO values, peak expiratory flow(PEF), expiratory flow rate 75%(TEF75), expiratory flow rate 50%(TEF50), expiratory flow rate 25%(TEF25), EOS counts, peripheral blood leukocyte counts, neutrophilic granulocyte percentage and CRP. Analyze the best cut-off value of Fe NO between asthmatic children and healthy children by ROC. Discuss the correlation among Fe NO and EOS and lung function parameters by Spearman’s correlation. The remission stage group children were divided into two groups according peripheral blood leukocyte counts(>12×109/L and <12×109/L), asthma with high-leukocyte group and asthma with normal-leukocyte group. Analyze the influence of peripheral blood leukocyte counts and neutrophilic granulocyte percentage and CRP to Fe NO values. Statistical analyses were performed using SPSS 13.0. Normality test of measurement data were carried out. If the data accord with normal distribution, they would be presented as means±SD( x ±s), data of skewed distribution be presented as M(P25,P75). If Fe NO levels were normally distributed, all groups were compared using the variance analysis, otherwise, using Kruskl-Wallis H test. Every two groups were compared by Two-samples T test, if the data according with normally distribution, otherwise, by Mann-Whitney U test. The cut-off value of Fe NO between asthmatic children and control group was analyzed by receiver operating characteristic(ROC) curve. Correlations among Fe NO levels and asthma stages, EOS counts and lung function were examined using Spearman’s correlation. P values <0.05 were statistically significant.Results:The medians and quartile ranges of Fe NO for 3 groups were [20.90(14.80, 29.50)]ppb(acute stage group), [19.50(15.60, 24.50)]ppb(remission stage group) and [13.50(12.00, 18.00)]ppb(the controls)(P<0.001). The correlation among Fe NO values and EOS counts and lung function parameters(PEF、TEF75、TEF50、TEF25) had no statistical significance and the correlation coefficient(r=-0.08, 0.08,-0.06,-0.09, P>0.05). And the asthma stages(acute stage and remission stage) produced no impact on the relationship. The best cut-off value of Fe NO between asthmatic children and control group is 20.50 ppb by ROC curve. The medians and quartiles of Fe NO in asthma children with high-leukocyte group were [16.00(12.80, 34.90)] ppb in acute stage group, [30.07(18.08, 36.30)] ppb in remission group and the [13.50(12.00, 18.00)] ppb in control group(P<0.001). The average neutrophilic granulocyte percentages of remission group were(52.38±3.87)% for high-leukocyte group and(43.28±4.56) % for normal-leukocyte group(P>0.05); the CRP values were(13.64±2.35)mg/L for high-leukocyte group and(9.68±3.21)mg/L for normal-leukocyte group(P>0.05).Conclusion:1 The asthmatic children have higher Fe NO values than the healthy.2 The Fe NO values, EOS count and lung function parameters have no correlation, their meanings are irreplaceable in asthma children.3 20.50 ppb is considered to be the best cut-off value of Fe NO between asthmatic children and the healthy.4 High-leukocyte can decrease the Fe NO values in asthma children. |
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