Related Experiment Video
Updated: Jun 16, 2026

A Novel Inhalation Mask System to Deliver High Concentrations of Nitric Oxide Gas in Spontaneously Breathing Subjects
Published on: May 4, 2021
Alveolar and bronchial exhaled nitric oxide in chronic obstructive pulmonary disease
An Lehouck1, Claudia Carremans, Kristien De Bent
1Respiratory Division, University Hospital Gasthuisberg; Katholieke Universiteit Leuven, Herestraat 49, Bus 706, 3000 Leuven, Belgium. an.lehouck@med.kuleuven.be
Background:
Fractional exhaled NO (Fe,NO) has yielded inconsistent results in COPD. Measuring exhaled NO at multiple flow rates however, allows to dissect exhaled NO in an alveolar (CAlv,NO) and bronchial (J'aw,NO) fraction, which are claimed to better reflect the bronchial and alveolar inflammation in COPD. We examined whether the use of Fe,NO, CAlv,NO and J'aw,NO may contribute to the clinical diagnosis of COPD.
Methods:
One hundred and fifty one patients were included in this case-control design: 28 healthy nonsmokers, 39 healthy smokers, 55 COPD nonsmokers and 29 COPD smokers. Prior to spirometry, exhaled NO was measured at three different flow rates (50, 100 and 200 ml/s; NIOX-FLEX) from which Fe,NO, CAlv,NO and J'aw,NO were calculated.
Results:
Mean Fe,NO, mean CAlv,NO and mean J'aw,NO of healthy individuals were not significantly different from COPD patients and none of these variables correlated with FEV(1). In both healthy and COPD patients, current smoking significantly reduced Fe,NO, J'aw,NO and CAlv,NO. Multivariate analysis demonstrated that in contrast to gender, age, BMI, GOLD stage and the use of inhaled corticosteroids, current smoking was the only variable affecting CAlv,NO. (p=0.0115)
Conclusion:
We conclude that similar to single breath exhaled NO, exhaled NO at different flow rates does not contribute to the diagnosis of COPD in standard respiratory practice.
Related Concept Videos
Chronic Obstructive Pulmonary Disease III: Chronic Bronchitis Features
Chronic Obstructive Pulmonary Disease-IV: Assessement and Diagnostic Studies
Medical History
Chronic Obstructive Pulmonary Disease II: Emphysema
Chronic Obstructive Pulmonary Disease-II: Pathophysiology
Chronic Inflammation
Chronic Obstructive Pulmonary Disease
Smoking is a primary risk factor for COPD, with over 80% of patients having a history of it. Patients typically experience progressive dyspnea or labored breathing, frequent coughing, and recurrent pulmonary infections. Many eventually succumb to respiratory failure, characterized by...
COPD: Pathogenesis and Clinical Features
The primary cause for the onset of COPD is cigarette smoking and exposure to air pollution. These hazardous factors initiate a chain reaction within the lungs, resulting in chronic inflammation, damage to the airways, and a...
