2008 – “eNO and PC20 – What to Expect?”
Joint with A Antunes, J gomes, M. Guimarães, L. costa J. Machado and B. Parente
Revista Portuguesa de Pulmonologia, Volume 14, Supplement 4-179 (Conference proceedings)
Abstract:Before the clinical suspect of asthma, one of the the pulmonary function tests we can conduct is bronchoprovocation testing, which measures bronchial hyperresponsiveness. On the basis of asthmatic illness, underlies inflammation and with the possibility of quantifying that inflammation with easy, non-invasive tests, such as measurement of exhaled Oxide Nitric (eNO), is important to checkout how the results of these two test are related. 106 patients who were clinically suspect of suffering from asthma were referenced to our Laboratory of Respiratory Physiopathology and included in this study. Applying regression analysis, we see that average eNO value of the patients that tested negative (PC20>8) in the methacholine is 21.762ppb and on average a patient tested positive on the methacholine test has a eNO value 12.928ppb higher than a patient tested negative, being these results statistically significant at the 1% level. These results corroborate previous studies, where asthmatic patients have eNO values higher than not-asthmatic. However, although this study show us that positive methacholine test is correlated with an eNO measurement higher than patients with negative test (12.928 on average) it does not give us a eNO cut-off to predict a positive methacholine test, since eNO is dependent of other factors (sex, weight, smoking habits).