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Ann Am Thorac Soc. 2015 Jul;12(7):1039-43. doi: 10.1513/AnnalsATS.201412-571BC.

Comparison of the provocative concentration of methacholine causing a 20% fall in FEV1 between the AeroEclipse II breath-actuated nebulizer and the wright nebulizer in adult subjects with asthma.

Author information

1
1 Department of Medicine, McMaster University, Hamilton, Ontario, Canada; and.
2
2 Department of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.

Abstract

RATIONALE:

The American Thoracic Society guidelines for methacholine testing for the diagnosis of asthma recommends the 2-minute tidal breathing protocol with the Wright nebulizer, which produces more aerosol than required, generates a small particle size, and requires cleaning between tests.

OBJECTIVES:

To evaluate methacholine testing using a disposable, breath-actuated AeroEclipse II, which produces aerosol during inspiration and was developed for single-patient use.

METHODS:

Forty-six adult subjects with asthma (19 men), aged 27.3 (SD, 9.5) years, with FEV1 98.5 (SD, 18.1) % predicted participated in a randomized, crossover, observational study. Subjects were first screened using the Wright nebulizer, then assigned to 2 minutes of tidal breathing from the Wright or 20 seconds of tidal breathing from the AeroEclipse nebulizer on 2 separate days, in random order. Provocative concentration of methacholine causing a 20% fall in FEV1 (PC20) values were calculated by linear interpolation of log dose-versus-response curves, log-transformed, and compared using paired Student t test and Pearson correlation.

MEASUREMENTS AND MAIN RESULTS:

The 38 subjects demonstrating reproducible PC20 measurements of within 1.5 doubling concentrations were included in the comparison. The geometric mean methacholine PC20 measured with the AeroEclipse nebulizer was approximately 1 doubling concentration lower than the geometric mean methacholine PC20 of the Wright nebulizer (Pā€‰<ā€‰0.05). The Pearson correlation coefficient between the two nebulizers was 0.86 (Pā€‰<ā€‰0.05).

CONCLUSIONS:

The PC20 measurements using the two nebulizers were highly correlated; however, the PC20 determined with the AeroEclipse nebulizer was significantly lower than those determined using the Wright nebulizer. Clinical trial registered with www.clinicaltrials.gov (NCT 01919424).

KEYWORDS:

airway hyperresponsiveness; asthma; nebulizer

PMID:
25871542
DOI:
10.1513/AnnalsATS.201412-571BC
[Indexed for MEDLINE]

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