Supporting the diagnosis of non-specific respiratory symptoms in primary care: the role of exhaled nitric oxide measurement and spirometry.
OBJECTIVE
To assess whether exhaled nitric oxide (FENO) measurements improve management and clinician confidence in patients presenting with non-specific respiratory symptoms.


METHODS
This observational study was based in a large primary care practice (15,500 patients, 14 GPs). Patients had non-specific respiratory symptoms for at least six weeks. FENO and spirometry measurements were performed at initial assessment. An algorithm was employed to assist interpretation of FENO and spirometry results. GPs evaluated the diagnostic contribution of FENO and spirometry at 3- month follow-up.


RESULTS
In 48/51 (94%) of cases FENO was considered significant in formulating a diagnosis. Spirometry was deemed helpful in 27/51 (54%).


CONCLUSIONS
FENO measurements improved diagnostic confidence when assessing non-specific respiratory symptoms. This may be because, in contrast to spirometry, both low and high FENO values have clinical significance.


BACKGROUND
Australian Clinical Trials Registry ACTRN012605000354684.
Hewitt
Richard S
RS
Research Fellow, Respiratory Research Department, Dunedin School of Medicine, Dunedin, New Zealand.
Modrich
Catherine M
CM
Medlicott
Timothy
T
Cowan
Jan O
JO
Taylor
D Robin
DR
D000293:Adolescent; D000328:Adult; D001944:Breath Tests; D002648:Child; D015331:Cohort Studies; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism*; D011320:Primary Health Care; D015203:Reproducibility of Results; D012140:Respiratory Tract Diseases / Q000175:diagnosis* / Q000378:metabolism / Q000503:physiopathology; D013147:Spirometry
D009569:Nitric Oxide