Metered-dose inhaler to deliver methacholine in bronchial provocation testing: a pilot study.
BACKGROUND
Nonspecific bronchial provocation tests may be simplified by the use of hand-held devices to deliver methacholine.


OBJECTIVE
To study the feasibility of using a metered-dose inhaler (MDI) to administer methacholine in bronchial provocation tests, and the ability of such a device to diagnose bronchial hyperresponsiveness (BHR) accurately.


METHODS
In an open randomized crossover pilot study, we compared the provocative dose that induces a 20% fall in FEV1 (PD20 FEV1) obtained with the methacholine MDI with that obtained using a conventional nebulizer in 20 hyperresponsive and 20 nonhyperresponsive subjects. The MDI delivers 400 doses of 100 microg of methacholine, and was used via a spacer. Bronchial hyperresponsiveness (BHR) was defined as a PD20 FEV1 <2,000 microg with the conventional test using the nebulizer. The tests were performed in each subject in a randomized order, 1 to 7 days apart.


RESULTS
Of the subjects who had a nebulizer PD20 FEV1 <2,000 microg, all but one had an MDI PD20 FEV1 <800 microg. When 800 microg was taken as the threshold for the diagnosis of BHR with the MDI test, the accuracy of this test to diagnose BHR was 97.5%, and the two tests were highly concordant for the diagnosis of BHR (Pearson chi2, 36.19; p<0.0001).


CONCLUSIONS
A hand-held device may be suitable for delivery of methacholine during bronchial provocation tests, if these results are confirmed in large samples.
Roche
N
N
Laboratoire de Biologie et Pharmacologie des Epithéliums Respiratoires, Université de Paris René Descartes, Boulogne, France.
El Husseini
F
F
Labrune
S
S
Giraud
V
V
Chinet
T C
TC
Huchon
G J
GJ
D000328:Adult; D016535:Bronchial Hyperreactivity / Q000175:diagnosis; D001985:Bronchial Provocation Tests / Q000295:instrumentation*; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D008297:Male; D016210:Methacholine Chloride / Q000008:administration & dosage*; D009330:Nebulizers and Vaporizers; D010865:Pilot Projects
D016210:Methacholine Chloride