Asthma
Conditions
Keywords
Mannitol, Methacholine, Deep inhalation, Tidal breathing
Brief summary
The study will assess how the inhalation technique used (deep inhalations versus tidal breathing) influences the results of a mannitol challenge test and a methacholine challenge test, if at all.
Detailed description
This study will look at airway responsiveness to inhaled methacholine and mannitol administered with and without deep inhalation. This study will also investigate the role of airway inflammation on these responses, using sputum differential cell counts and fractional exhaled nitric oxide. This is a single center, open label, randomized study. Individuals with stable asthma will be eligible for enrollment. The study will consist of two parts, screening and testing. Part 1: Screening Participants will undergo consent procedures and assessments of fractional exhaled nitric oxide levels, airway responsiveness to methacholine and sputum induction. If participants show airway responsiveness to methacholine (i.e. methacholine PC20 16mg/mL), they will be scheduled to undergo the testing part of the study. Part 2: Testing Participants will be randomized to undergo two methacholine or two mannitol challenges. Further randomization will occur with respect to whether the standard challenge method or the modified challenge method is performed first.
Interventions
PROCEDUREDeep inhalation technique
Use of deep inhalations for administration of inhalant
PROCEDURETidal breathing technique
Use of tidal breathing for administration of inhalant
DRUGMethacholine
Methacholine direct bronchoconstrictor used for bronchoprovocation challenge
DRUGMannitol
Mannitol indirect bronchoconstrictor used for bronchoprovocation challenge
Sponsors
University of Saskatchewan
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
OTHER
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 75 Years
Healthy volunteers
No
Inclusion criteria
* signed informed consent * men and women between 18 and 75 years of age * FEV1 at first measurement of greater than or equal to 65% predicted * methacholine provocative concentration causing a 20% in FEV1 at screening that is less than or equal to 16mg/ml * generally good health * stable asthma
Exclusion criteria
* respiratory infection within 4 weeks of screening visit * worsening of asthma within 4 weeks of screening visit * lung disease other than asthma * significant medical comorbidity * current smoker or ex-smoker with significant smoking history * currently pregnant or breastfeeding
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Effect of deep inhalation (versus tidal breathing) on mannitol provocative dose causing a 15% fall in forced expiratory volume in one second (FEV1) | 24 hours between mannitol challenges | Shift in mannitol provocative dose causing a 15% fall in forced expiratory volume |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Effect of airway inflammation on methacholine and mannitol challenge results-fractional exhaled nitric oxide | up to 2 weeks, from baseline to end of study | Collection of fractional exhaled nitric oxide at screening - analysis of resulting measurement indicative of degree of baseline airway inflammation |
| Effect of airway inflammation on methacholine and mannitol challenge results-sputum | up to 2 weeks, from baseline to end of study | Collection of sputum at screening - analysis for differential cell counts indicative of degree of baseline airway inflammation |
| Effect of deep inhalation (versus tidal breathing) on methacholine provocative | 24 hours between methacholine challenges | Shift in methacholine provocative dose causing a 20% fall in forced expiratory volume |
Countries
Canada
Outcome results
None listed