Domiciliary diurnal variation of exhaled nitric oxide fraction for asthma control

Abstract

A major goal of asthma management is maintaining optimal control. Current assessment is based on symptoms and lung function.We evaluated whether domiciliary daily home exhaled nitric oxide fraction (FeNO) monitoring could be useful as an index of asthma control. 50 asthmatic subjects and 15 healthy volunteers with a range of asthma severity underwent asthma control questionnaire (ACQ), spirometry before and after salbutamol and sputum induction. FeNO and peak expiratory flow (PEF) were measured twice daily for 2 weeks. A record of exacerbations was obtained 3 months later.Diurnal FeNO variation in uncontrolled asthmatics was significantly greater than in controlled asthmatics (p,0.01). PEF variation was not different. The daily variation of FeNO levels was also greater in uncontrolled asthmatics compared with controlled asthmatic and healthy subjects (p,0.01). 80% of uncontrolled asthmatics experienced at least one or more exacerbations over the 3 months after the enrolment. The combination of diurnal FeNO variation o16.6% and ACQ scores o1.8 was best at predicting uncontrolled asthma (area under curve 0.91, 95% CI 0.86-0.97; p,0.001).Diurnal variation in FeNO can be used as a biomarker of asthma control and as a predictor of the risk of future exacerbation. Prospective studies are warranted. @ERSpublications Diurnal variation in FeNO can be used as a biomarker of asthma control and a predictor of the risk of future exacerbation

The Clinical Relevance of Periostin in Asthma

“…As with healthy adults, mean serum periostin levels in asthma patients reduce gradually during the day with a fall of approximately 5%, from 53.5 ng/ml at 0800 hr to 50.9 ng/ml at 1800 hr 43 . This daytime variation is similar to that observed in other type-2 biomarkers such as sputum and blood eosinophils [60][61][62][63][64] , and FeNO [65][66][67] which are higher in the early morning compared with late afternoon or evening. This suggests that the time of day in which a blood sample is taken is unlikely to influence clinical decision-making for asthma patients.…”

A European Respiratory Society technical standard: exhaled biomarkers in lung disease

“…Bronchoconstriction may cause a decrease in FENO 50 and bronchodilation an increase [245,246]. FENO 50 can vary in uncontrolled asthma and is proposed to be a biomarker of asthma control and a predictor of exacerbation [247]. Drugs that may affect airway calibre should be documented as well as anti-inflammatory drugs.…”

Application of nitric oxide measurements in clinical conditions beyond asthma

“…However, as disease activity shows day to day variation, and even variation within the same day, it is desirable to perform more frequent measurements. An increased diurnal variability in FeNO levels was associated with loss of asthma control whereas peak flow variability did not differ between controlled and uncontrolled asthmatics ( 134 ). We also need to know whether NO measurements on a regular, preferably daily, basis can help to predict a deteriorating disease beyond asthma.…”