[Correlation between fractional exhaled nitric oxide and airway reversibility in children with IgE-mediated asthma].

Objective: To study the correlation between fractional exhaled nitric oxide (FeNO) and airway reversibility in children with IgE-mediated asthma.

Methods: A total of 86 children, aged 6-14 years, who were initially diagnosed with acute attack of asthma from September 2016 to August 2018 were enrolled as subjects. According to the results of serum specific IgE, they were divided into IgE mediated group with 61 children and non-IgE mediated group with 25 children. According to the results of allergen detection, the IgE mediated group was further divided into four groups with one, two, three, and four or more positive allergens. FeNO and the parameters of pulmonary ventilation function before and after dilation test were measured. Pearson correlation analysis was used to evaluate the correlation of FeNO with each parameter of pulmonary function.

Results: The IgE mediated group had significantly higher FeNO than the non-IgE mediated group (P<0.05). FeNO increased with the increase in the number of positive serum specific allergens (P<0.05). In the IgE mediated group, FeNO level was positively correlated with the change in forced expiratory volume in the first second (FEV1) and the improvement in percentage of predicted FEV1 after medication in bronchial dilation test (r=0.655 and 0.473 respectively, P<0.05). The FeNO level was not correlated with FEV1, percentage of predicted FEV1, peak expiratory flow (PEF), change in PEF after medication, percentage of predicted PEF (PEF%pred), and improvement in PEF%pred after medication (P>0.05). In the non-IgE mediated group, FeNO level was not correlated with the above indicators (P>0.05).

Conclusions: FeNO level is associated with the degree of allergies. For children with IgE-mediated asthma, FeNO is positively correlated with airway reversibility, which has a certain value in the diagnosis of asthma, disease evaluation, and understanding of airway reversibility. For children with non-IgE-mediated asthma, FeNO cannot be used to evaluate airway reversibility. These two types of asthma should be treated differently.