Exhaled nitric oxide in the diagnosis and management of asthma.
OBJECTIVE
Gaseous nitric oxide is present in our exhaled breath and may be a biomarker for asthma. The purpose of the present paper is to review recent studies that have explored the potential of exhaled nitric oxide as a biomarker for asthma diagnosis and treatment.


RESULTS
The upper limit of exhaled nitric oxide has been described in several populations, using a standard methodology. Measurements of exhaled nitric oxide have good specificity but relatively poor sensitivity for diagnosing asthma. The inter- and intra-subject variability of exhaled nitric oxide values in asthmatics remains uncertain. Clinical trials have used exhaled nitric oxide to guide steroid treatment in asthmatics with varied success. The greatest success is in studies where inhaled corticosteroids are reduced and/or withdrawn in stable asthmatics. These pioneering clinical trials have given insight into how exhaled nitric oxide might be a useful index of control of eosinophilic airway inflammation.


CONCLUSIONS
Measurements of exhaled nitric oxide have the potential to be useful in the management of allergic asthma and the answers to a number of important questions are awaited.
Turner
Steve
S
Department of Child Health, University of Aberdeen, Aberdeen, UK. s.w.turner@abdn.ac.uk
D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D001249:Asthma / Q000175:diagnosis* / Q000378:metabolism / Q000628:therapy; D029662:Betula; D001944:Breath Tests; D002675:Child, Preschool; D002986:Clinical Trials as Topic; D045853:Exhalation; D006801:Humans; D009569:Nitric Oxide / Q000032:analysis* / Q000378:metabolism; D011237:Predictive Value of Tests; D006255:Rhinitis, Allergic, Seasonal / Q000175:diagnosis; D014221:Triamcinolone / Q000627:therapeutic use
D000305:Adrenal Cortex Hormones; D014221:Triamcinolone; D009569:Nitric Oxide