The Use of Exhaled Nitric Oxide Monitoring in Primary Care Asthma Clinics: a Pilot Study

Aim: Although asthma is defined as a chronic inflammatory disease, inflammation is rarely assessed. The fraction of exhaled nitric oxide (FeNO) is a biomarker of airways inflammation. We assessed the feasibility of FeNO monitoring in general practice.

Methods: Prospective observational study of volunteers attending primary care asthma clinics. Consenting subjects were seen at their own surgery for 2-weekly reviews over 12 weeks, with assessment of FeNO, lung function, symptoms and health status.

Results: 22 adults and 15 children provided informed consent. Two subjects were unable to perform the FeNO expiratory manoeuvre. In the remaining subjects, measurements conforming to highest ERS/ATS recommendations were made on 211 of 236 occasions, and on 21 further occasions acceptable readings were made. Acceptability was high to subjects and staff. Correlations between FeNO readings and other parameters were weak and non-significant except for statistically significant correlation between longitudinal FeNO changes and changes in lung function (r= -0.33, p<0.001) and health status (r= -0.22, p=0.022).

Conclusions: Exhaled nitric oxide monitoring is technically feasible and acceptable to staff and patients within the context of a primary care asthma clinic.