The National Heart Lung and Blood Institute guidelines finally say “yes” to fractional exhaled nitric oxide

Abstract

Exhaled nitric oxide levels were first discovered to be elevated in patients with asthma in 1993, only 2 years after the first National Heart Lung and Blood Institute (NHLBI) asthma guidelines were published. 1 Alving K Weitzberg E Lundberg JM. Increased amount of nitric oxide in exhaled air of asthmatics. Eur Respir J. 1993; 6: 1368-1370 PubMed Google Scholar Since then, more than 3600 articles have been published relating to the measurement of fractional exhaled nitric oxide (FeNO) in asthma, with an average of almost 20 articles per month being published over the past 10 years. Despite our growing understanding of the use of FeNO as a tool to assist in the evaluation and management of asthma, it has seen a particularly slow uptake among practitioners in the United States, especially in comparison to its wider acceptance and uses in other parts of the world including the United Kingdom and European Union. In 2011, the American Thoracic Society published evidence-based guidelines on the clinical use of FeNO 2 Dweik RA Boggs PB Erzurum SC Irvin CG Leigh MW Lundberg JO et al. An official ATS clinical practice guideline: interpretation of exhaled nitric oxide levels (FENO) for clinical applications. Am J Respir Crit Care Med. 2011; 184: 602-615 Crossref PubMed Scopus (1677) Google Scholar ; however, the regularly updated international Global Initiative for Asthma guidelines did not adopt or endorse these recommendations at that time. 3 Global Initiative for Asthma. Global strategy for asthma management and prevention. 2020. Available at: http://www.ginasthma.org. Accessed September 25, 2021. Google Scholar The lack of consensus guidelines has, in part, been responsible for the slow adoption of FeNO by practitioners as a unique, clinically meaningful, and important tool in the diagnosis and management of asthma, and this has also led to several third-party payers denying payment and citing its use as “experimental.”