Elsevier

Respiratory Medicine

Volume 96, Issue 11, November 2002, Pages 895-900
Respiratory Medicine

Regular Article
Short-term variability of exhaled nitric oxide in young male patients with mild asthma and in healthy subjects

https://doi.org/10.1053/rmed.2002.1378Get rights and content
Under an Elsevier user license
open archive

Abstract

Background: Exhaled nitric oxide (NOexp) is an indicator of eosinophilic airways inflammation. This study evaluated short-term variability of NOexp in 13 healthy subjects (19–41 years, eight males) and in 31 patients with asthmatic respiratory symptoms (19–21 years, all male) to obtain data for assessment of short-term changes of NOexp in clinical situations. Methods: Mild asthma was confirmed in 10 patients (Group = asthma). Twenty-one patients with asthmatic respiratory symptoms did not fulfill the functional criteria of asthma (Group = respiratory symptoms). The procedure to determine NOexp followed the European Respiratory Society (ERS) guidelines; the mean expiratory flow used during sampling was 0.09—0.12 l/s. NOexp for each subject was determined as the mean of at least three successive measurements at the baseline, followed by determinations at 10 min, 6 h and 24 h after the baseline. Results: At the baseline, the mean (sd) value of NOexp was 6.6 (2.3) parts per billion (ppb) in the healthy controls, and significantly higher both in patients with respiratory symptoms (14.6 (11) ppb,P = 0.0076) and in those with asthma (34.2 (43) ppb, P<0.001). Intra-class correlation coefficient of NOexp measured at baseline and after an interval of 10 min was 0.959 in healthy subjects, 0.986 in patients with respiratory symptoms and 0.936 in asthma patients, respectively. Short-term variability in terms of coefficient of variation (Co V) of repeated measurements of NOexp at 10 min, 6 h and 24 h was 5.1, 10.8 and 11.7% in healthy subjects, 7.1, 16.4 and 22.2% in patients with respiratory symptoms and 13.5, 19.4 and 26.4% in asthma patients, respectively.Conclusions: Reproducibility of NOexp using standardized methods was good both in healthy subjects and in asthmatic patients. However, in asthmatics the short-term variation of NOexp was over two times as high as in healthy subjects. The level of NOexp was elevated, except in asthma, also in patients with asthmatic respiratory symptoms who did not fulfill the functional criteria of asthma.

Keywords

exhaled nitric oxide
variability
healthy subjects
asthma.

Cited by (0)

f1

Correspondence Should be addressed to: Prof. Dr. Anssi Sovijärvi, MD, PhD, Laboratory of Clinical Physiology, Helsinki University Hospital, PL 340, 00029 HUS, Helsinki, Finland. Fax: +358 9 471 74592; E-mail: [email protected]