Fractional nitric oxide measurement in exhaled air (FeNO): perspectives in the management of respiratory diseases

Abstract

Exhaled nitric oxide (NO) production, upregulated by inflammatory cytokines and mediators in central and peripheral airways, can be easily and non-invasively detected in exhaled air in asthma and other respiratory conditions as a promising tool for disease monitoring. The American Thoracic Society and European Respiratory Society released recommendations that standardize the measurement of the fractional exhaled NO (FeNO). In asthma, increased FeNO reflects eosinophilic-mediated inflammatory pathways and, as a biomarker of T2 inflammation can be used to identify asthma T2 phenotype. In this setting its measurement has shown to be an important tool especially in the diagnostic process, in the assessment and evaluation of poor adherence or predicting positive response to inhaled corticosteroids treatment, in phenotyping severe asthma patients and as a biomarker to predict the response to biologic treatments. The discovery of the role of NO in the pathogenesis of different diseases affecting the airways and the possibility to estimate the predominant site of increased NO production has provided new insight on its regulatory role in the airways, making it suitable for a potential extended use in clinical practice for different pulmonary diseases, even though its role remains less clear than in asthma. Monitoring FeNO in pulmonary obstructive lung diseases including chronic bronchitis and emphysema, interstitial lung diseases, obstructive sleep apnea and other pulmonary diseases is still under debate but has opened up a window to the role NO may play in the management of these diseases. The use of FeNO is reliable, cost effective and recommendable in both adults and children, and should be implemented in the management of patients with asthma and other respiratory conditions.

The Fractional exhaled Nitric Oxide (FeNO)- test as add-on test in the diagnostic work-up of asthma: a study protocol

“…The FeNO-test (Niox-Vero, Aerocrine AB, Sweden) will be measured at a constant flow rate of 50 mL/s and expressed as ppb following the guidelines [ 11 , 12 ]. The FENO measurements are performed with a deep inhalation through the mouth and slow exhalation (constant flow rate of 50 mL/s).…”

The Accuracy and Utility of Nasal FeNO Measurement with Handle Device in Patients with Allergic Rhinitis: A Single Center Study

“…There are different techniques used to measure exhaled NO concentration and the most commonly used is chemiluminescence. This technique is highly sensitive and exhaled NO can be detected at part per billion, allowing a direct measurement of exhaled NO in subjects with upper and lower airway diseases [8][9][10]. Recently a new NO analysis method based on an electroluminescent technique has been developed and used for measuring exhaled NO [11,12].…”

Lung Involvement in Patients with Ulcerative Colitis: Relationship between Exhaled Nitric Oxide and Lung Function

“…Some reports have indicated that these abnormalities also persist and have been observed during clinical remission of the disease, suggesting a latent subclinical inflammatory reaction [5]. Among recent, straightforward, non-invasive methods for assessing airway inflammation, fractional exhaled nitric oxide (FeNO) measurement has proven effective in detecting and safely monitoring airway inflammatory status in various clinical conditions, in both adults and children [6]. Standardized procedures for measuring FeNO concentration have gained approval from the American Thoracic Society (ATS) and the European Respiratory Society (ERS) [7,8].…”