Utilising exhaled nitric oxide information to enhance diagnosis and therapy of respiratory disease – current evidence for clinical practice and proposals to improve the methodology

ABSTRACT

Introduction: A non-invasive tool to diagnose respiratory diseases and to follow treatment has long been looked-for. Exhaled nitric oxide (NO) is a promising marker of inflammation in asthma but nearly 25-years of research has shown that it works in only certain endotypes of asthma. The modelling of NO dynamics of the lung can give more information than a single F_ENO value.

Areas covered: The estimation of the NO production in the conducting airways and in the gas exchange area has given new insight of the NO production in diseases beyond asthma. In this article, we discuss the importance of methodology for NO measurement in the exhaled breath and the indication of applying this technique to detect respiratory disorders. This narrative review is an attempt to examine and discuss the physiological basis underlying exhaled NO measurements and the clinical evidence of the usefulness of this method in asthma and various other respiratory disorders.

Expert commentary: Estimation of the NO parameters would aid in our understanding of the NO dynamics of the lung and thereby give more knowledge how to interpret the measured F_ENO value in clinical practice.

KEYWORDS:

• Asthma
• F_ENO
• modelling
• COPD
• primary ciliary dyskinesia
• obstructive sleep apnoea
• systemic sclerosis
• two-compartment model
• nitric oxide
• interstitial lung diseases

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Additional information

Funding

Part of this work has been funded by the Legs Poix (Paris Universities) and the Air Liquide Foundation.