Original Article
The Use of Exhaled Nitric Oxide in the Diagnosis of Asthma in School Children

https://doi.org/10.1016/j.jpeds.2009.02.034Get rights and content

Objectives

To evaluate the yield of the fractional exhaled nitric oxide (FeNO) in the diagnosis of asthma compared with spirometry and induced sputum cytologic study in school-age children.

Study design

Consecutive children referred for evaluation of possible asthma were included. At referral, all children completed FeNO measurement, sputum induction for eosinophil count (eos%) and spirometry. The diagnosis of asthma was performed after 18 months with conventional criteria. Receiver operating curves were used to determine cutoff points for disease status, and accuracy was calculated.

Results

A total of 150 children were included: 69 with steroid-naïve asthma, 44 without asthma, and 37 with asthma treated with controllers. FeNO and eos% levels were significantly higher in those with steroid-naïve asthma (P < .0001). The area under the receiver operating curve for FeNO and eos% were very high compared with forced expiratory volume in 1second (0.906, 0.921, 0.606, respectively). The sensitivity, specificity, and positive and negative predictive values for best cutoff points of FeNO (19 parts per billion) were 80%, 92%, 89%, and 86%, respectively, and were similar to eos% (best cutoff = 2.7%): 81%, 92%, 89%, 85%, respectively.

Conclusions

FeNO measurement is useful in early diagnosis of pediatric asthma. We suggest considering FeNO measurement in the evaluation of children suspected of having asthma, especially in cases where the diagnosis is not clear.

Section snippets

Methods

Consecutive children referred for possible asthma to the outpatient pediatric pulmonary clinic of the Dana Children's Hospital at the Tel-Aviv Medical Center were included. Inclusion criteria were (1) nonspecific respiratory symptoms suggestive of asthma for at least 3 months' duration, including cough, wheezing, and shortness of breath with or without trials of treatment with bronchodilators and inhaled corticosteroids; (2) children were cooperative and successfully completed all 3 tests: FeNO

Results

One-hundred fifty children completed all 3 tests and complied with the inclusion and exclusion criteria. All were Caucasian. Six children who were unable to produce adequate sputum were not included in the study. Symptoms for which patients were referred were cough (n = 41), dyspnea (n = 31), wheezing episodes (n = 23), dyspnea on exercise (n = 9), cough and dyspnea (n = 19), cough and wheeze (n = 13), and dyspnea and wheeze (n = 14). None of the children were receiving long-acting beta 2

Discussion

This study demonstrates that FeNO in children with asthma is significantly increased when compared with patients with similar symptoms in the absence of asthma. The measurement of FeNO as an inflammatory biomarker in patients with clinical suspicion of asthma provides very similar results to eosinophil count in induced sputum and offers a significantly higher diagnostic yield than the standard approach on the basis of spirometry.

A number of studies reported good sensitivity and specificity for

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    The authors declare no conflicts of interest.

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