The role of FENO and spirometry in the evaluation of obstruction in pediatric asthma.

INTRODUCTION The fractional exhaled nitric oxide concentration (FENO) is used as a noninvasive biomarker for asthmatic inflammation. The role in establishing an asthma diagnosis is still under research. Spirometry remains the main investigation for the diagnosis and monitoring of asthma. OBJECTIVES The aim of the study was to assess the correlation between FENO level and the values of spirometric parameters defining airflow obstruction. MATERIALS AND METHODS The longitudinal study included a group of 89 children admitted to the Pediatric Clinic of "Grigore Alexandrescu" Emergency Clinical Hospital for Children. The inclusion criteria were: (i) a previously known diagnosis of asthma, (ii) age range between 5 and 18 years old. All patients underwent pulmonary function testing and measurement of FENO. RESULTS Significant correlations were identified between FENO and a part of spirometric parameters: MEF75 (p=0.007), MEF50 (p=0.0.28), MEF25 (p=0.011) and PEF (p=0.020), but not with FEV1 (p=0.090), nor FVC (p=0.308). However, multiple linear regression analysis revealed that spirometric parameters poorly predict FENO variation (R=0.062, p=0.82). In adition, binary logistic regression analysis (LR) showed that FENO can not be used as a reliable biomarker (p=0.169) for the estimation of the risk for obstructive dysfunction. CONCLUSION The level of exhaled nitric oxide does not correlate with the values of spirometric values. More studies with a large number of patients are needed for establishing the role of FENO in the evaluation of airflow obstruction.