Determining Responsiveness to Anti-inflammatory Therapy

An important benefit of measuring fractional exhaled nitric oxide (FeNO) is its ability to identify patients who are likely to benefit from treatment with corticosteroids.1

It has been shown that FeNO predicts the likelihood of steroid responsiveness more consistently than spirometry, bronchodilator response, peak flow variation, or airway hyperresponsiveness to methacholine.2-4

FeNO = fractional exhaled nitric oxide; ICS = inhaled corticosteroid.
*Increasing is defined as an increase >10 ppb from last measurement.
Chronic cough and/or wheeze and/or shortness of breath for >6 weeks.
For example, rhinosinusitis, bronchiectasis, primary ciliary dyskinesia, anxiety-hyperventilation, cardiac disease, gastroesophageal reflux disease, or vocal cord dysfunction.

References: 1. Dweik RA, Boggs PB, Erzurum SC, et al; on behalf of the American Thoracic Society Committee on Interpretation of Exhaled Nitric Oxide Levels (FeNO) for Clinical Applications. 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. 2. Knuffman JE, Sorkness CA, Lemanske RF Jr, et al; for the Childhood Asthma Research and Education Network of the National Heart, Lung, and Blood Institute. Phenotypic predictors of long-term response to inhaled corticosteroid and leukotriene modifier therapies in pediatric asthma. J Allergy Clin Immunol. 2009;123:411-416. 3. Szefler SJ, Martin RJ, King TS, et al; for the Asthma Clinical Research Network of the National Heart, Lung, and Blood Institute. Significant variability in response to inhaled corticosteroids for persistent asthma. J Allergy Clin Immunol. 2002;109:410-418. 4. Smith AD, Cowen JO, Brassett KP, et al. Exhaled nitric oxide: a predictor of steroid response. Am J Respir Crit Care Med. 2005;172:453-459.

Measuring FeNO may help healthcare providers avoid an empiric trial of steroids.1