Changes in exhaled nitric oxide and breath pH during fluticasone wean in asthma.
BACKGROUND
Inhaled corticosteroid (ICS) therapy improves asthma outcome. Both the anti-inflammatory efficacy and toxicities of ICS therapy are dose dependent. Therefore, there is interest in monitoring airway inflammation during ICS dose adjustments.


OBJECTIVE
Fraction of expired nitric oxide (FENO) and exhaled breath condensate (EBC) pH were studied as noninvasive, corticosteroid-responsive markers of airway inflammation.


METHODS
We prospectively studied the effect of stepwise ICS wean on FENO and EBC pH over 6 months in otherwise healthy adults with moderate persistent asthma.


RESULTS
Eighteen subjects completed the initial dose titration and 13 completed the protocol. Of these, 7 weaned off ICS completely and 6 had exacerbations. FENO rose significantly with ICS withdrawal, though there was heterogeneity in the starting level and the degree of rise. EBC pH was collected at home in all subjects and fell more in subjects who had an exacerbation than in those who did not. The decrease in pH was associated with hazard of exacerbation.


CONCLUSIONS
FENO can be a patient-specific index of airway inflammation during ICS dose titration; change in EBC pH is one home marker that might possibly be used during ICS dose titration. However, additional studies are required.
Departments of Pediatric Respiratory Medicine and Public Health Sciences, The University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
Lei
L
Liu
Peter
P
Urban
John F
JF
Hunt
Patricia
P
Wilkinson
Kappy
K
Laning
Benjamin
B
Gaston
D000293:Adolescent; D000328:Adult; D000730:Androstadienes / Q000008:administration & dosage; D001249:Asthma / Q000188:drug therapy / Q000378:metabolism*; D001944:Breath Tests; D001993:Bronchodilator Agents / Q000008:administration & dosage; D005260:Female; D000068298:Fluticasone; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism*; D011446:Prospective Studies; D013375:Substance Withdrawal Syndrome / Q000378:metabolism; D055815:Young Adult
D000730:Androstadienes; D001993:Bronchodilator Agents; D009569:Nitric Oxide; D000068298:Fluticasone