Exhaled Nitric Oxide in Children: A Noninvasive Marker of Airway Inflammation

• Published in: Archivos de bronconeumología (English ed.) 2008, Vol.44 (1), p.41-51
• Main Authors: Barroso, Nicolás Cobos, Pérez-Yarza, Eduardo G., Prado, Olaia Sardón, Bover, Conrado Reverté, Gartner, Silvia, Murua, Javier Korta
• Format: Article
• Language: eng ; spa
• Subjects: Asma; Asthma; Child; Children; Exhalation; Exhaled nitric oxide; Humans; Inflammation - diagnosis; Medidores portátiles; Methodology; Metodología; Nitric Oxide - analysis; Nitric Oxide - metabolism; Nitric Oxide - physiology; Niños; Portable analyzers; Respiration Disorders - diagnosis; Óxido nítrico exhalado
• ISSN: 1579-2129; 0300-2896; 1579-2129
• DOI: 10.1016/S1579-2129(08)60007-5

This article is an academic review of the application in children of the measurement of fractional exhaled nitric oxide (FE NO). We outline the joint American Thoracic Society/European Respiratory Society recommendations for online measurement of FE NO in both cooperating children and children unable to cooperate, offline measurement with uncontrolled exhalation flow rate, offline measurement with controlled exhalation flow rate using a dynamic flow restrictor, and offline measurement during tidal breathing in children unable to cooperate. This is followed by a review of the normal range of values for single-breath online measurements obtained with a chemiluminescence FE NO analyzer (geometric mean, 9.7 parts per billion [ppb]; upper limit of the 95% confidence interval, 25.2 ppb). FE NO values above 17 ppb have a sensitivity of 81% and a specificity of 80% for predicting asthma of an eosinophilic phenotype. We discuss the response of FE NO values to anti-inflammatory treatment and the use of this marker in the management of asthma. Results obtained with chemiluminescence and portable electrochemical analyzers are compared. The portable devices offer the possibility—in children over 5 years of age—of accurate and universal monitoring of exhaled nitric oxide concentrations, an emerging marker of eosinophilic inflammation in asthma that facilitates diagnosis, monitoring of disease progression, and assessment of response to therapy. En este artículo se presenta una revisión académica sobre la aplicabilidad de la medida de la fracción exhalada de óxido nítrico (FE NO) en niños. De acuerdo con las normas conjuntas de la American Thoracic Society/European Respiratory Society, se describen los métodos de medida on-line en niños colaboradores y no colaboradores, los registros off-line sin control de flujo de exhalación y con control de flujo de exhalación mediante restrictor de flujo dinámico, y el registro off-line a respiración corriente en niños no colaboradores. Se revisan los valores de normalidad, fundamentalmente con los analizadores de la FE NO por quimioluminiscencia, mediante registro on-line de una única respiración (media geométrica: 9,7 ppb -partes por mil millones-; límite superior del intervalo de confianza del 95%: 25,2 ppb). Los valores de la FE NO superiores a 17 ppb aportan un 81% de sensibilidad y un 80% de especificidad para predecir asma de fenotipo eosinofílico. Se analiza la respuesta de la FE NO al tratamiento antiinflamatorio y al seguimi