Can exhaled volatile organic compounds predict asthma exacerbations in children

Background: Asthma control falls short of current goals of asthma management guidelines. Non-invasive monitoring of airway inflammation may help to improve the level of asthma control in children. Aim: 1) To identify a set of exhaled volatile organic compounds (VOCs) that is most predictive for an asthma exacerbation in children. 2) To determine the chemical background of predictive VOCs. Methods: In an one-year prospective observational study, 96 asthmatic children were studied . At clinical visits with an interval of 2 months, asthma control, fractional exhaled nitric oxide, lung function (FEV 1 , FEV 1 /VC) and VOCs in exhaled breath by means of gas chromatography time-of-flight mass spectrometry, were determined. Random Forrest classification modeling was used to select predictive VOCs, followed by building of receiver operating characteristic-curves (ROC-curves). Results: An inverse relation between the predictive power of a set of VOCs and time between sampling of exhaled breath and the onset of an exacerbation was found. The sensitivity and specificity of the model predicting exacerbations 14 days after sampling were 88% and 75%, respectively. The area under the ROC-curve was 90%. The sensitivity for prediction of asthma exacerbations within 21 days after sampling was 63%. In total, 7 VOCs were selected for the classification model: 3 aldehydes, 1 hydrocarbon, 1 ketone, 1 aromatic compound, and 1 undefined VOC. Conclusion: VOCs in exhaled breath showed potential to predict asthma exacerbations in children within 14 days after sampling. Before use in clinical practice, the validity to predict asthma exacerbations should be studied in a larger cohort.