Relationship of exhaled nitric oxide to clinical and inflammatory markers of persistent asthma in children
Posted Mar 03 2010 10:07pm
Exhaled nitric oxide (eNO) is a noninvasive test that measures airway inflammation.eNO provides information about the asthmatic state consistent with information from other markers of inflammation. It is a noninvasive technique that could be used in decisional management of children with asthma.
Asthma control is monitored by means of symptoms using pulmonary function tests, particularly FEV1 and FEV1/forced vital capacity (FVC), to supplement the clinical information. There is growing interest in determining the role of biomarkers in asthma care. Most of these studies have been conducted in adults. Peripheral blood eosinophils,and sputum eosinophils correlate with response to oral corticosteroids. Studies in adults have shown that improved asthma control can be attained by use of airway responsiveness to methacholine and sputum eosinophils to modulate asthma therapy rather than waiting for clinical symptoms to appear or pulmonary functions to deteriorate. Because the application of biomarkers to assessment of asthma management has become more widespread, exhaled nitric oxide (eNO) has been studied to predict the clinical course with reductions in or response to medications. eNO levels correlate with response to inhaled corticosteroids (ICSs), in that patients with higher levels have better responses.Jones et al demonstrated that increases of eNO have a positive predictive value for loss of control of asthma as ICSs are withdrawn, providing information about control of asthma equal to induced sputum eosinophils and methacholine responsiveness. eNO is a particularly attractive biomarker, because the test requires little effort from the patient, can be measured even in young children,and the results of the test can be immediately available.