AeroEclipse II Agreement

• Methacholine inhalation challenge [ Time Frame: Visit 1(Day 1) ] [ Designated as safety issue: No ]
  A methacholine inhalation challenges will be performed at each of the first two visits. At the first clinic visit each subject will be randomly assigned to use either the English-Wright continuous-mode nebulizer, or the AeroEclipse II breath actuated nebulizer. The alternate nebulizer will be used during the second clinic visit. The methacholine concentration producing a 20% decrease in Forced Expiratory Volume in 1 second (PC20) will be measured by way of a standard breathing challenge (the tidal breathing Cockcroft technique)
• Methacholine inhalation challenge [ Time Frame: Visit 2 (up to 2 weeks) ] [ Designated as safety issue: No ]
  A methacholine inhalation challenges will be performed at each of the first two visits. At the first clinic visit each subject will be randomly assigned to use either the English-Wright continuous-mode nebulizer, or the AeroEclipse II breath actuated nebulizer. The alternate nebulizer will be used during the second clinic visit. The methacholine concentration producing a 20% decrease in Forced Expiratory Volume in 1 second (PC20) will be measured by way of a standard breathing challenge (the tidal breathing Cockcroft technique)

Traditional, continuous-mode nebulizers such as the English-Wright nebulizer are designed to operate continuously with tidal breathing. As inhalation accounts for only about one-third of the respiratory cycle, two-thirds of the continuously produced aerosol is lost to the environment possibly posing a hazard any fellow-patients, family members, or health-care workers in the vicinity. The English-Wright has been the only American Thoracic Society (ATS)recommended device available on the market. Recently Roxon Medi-Tech has announced the discontinuation of the English-Wright nebulizer. For these reasons it is necessary to review the use of other nebulizers such as the AeroEclipse II breath-actuated nebulizer and further validate their performance.

The investigators expect to show equivalence between the AeroEclipse II and the English-Wright nebulizers.

This study would like to determine if the use of the Aeroeclipse II breath actuated nebulizer for the delivery of methacholine chloride bronchoprovocation agent to the lungs results in the same Provocation Concentration PC20 (provocation concentration, or dose that causes a 20% decrease in Forced Expiratory Volume in 1 sec or FEV1) as using the English-Wright nebulizer for the delivery of methacholine chloride bronchoprovocation agent to the lungs.

• Device: AeroEclipse II breath-actuated nebulizer
  The AeroEclipse II (Trudell Medicinal International, London, ON, Canada) is a breath-actuated nebulizer that allows for the creation of aerosol only in response to the patient's inspiratory flow, resulting in virtually no drug loss to the environment and providing a safer healthcare and patient environment by significantly reducing second-hand drug exposure and the possibility for transmission of viral airborne pathogens.
• Device: English-Wright continuous-mode nebulizer
  The English-Wright is a continuous-mode nebulizer, designed to operate continuously with tidal breathing, producing an aerosol which is lost to the environment possibly posing a hazard to any fellow-patients, family members, or health-care workers in the vicinity. It is the only device recommended by the American Thoracic Society guidelines that is available on the market and it has recently been discontinued. For these reasons it is necessary to review the use of other nebulizers and validate their performance.

Inclusion Criteria:

1. Aged 10 to 65 years at time of recruitment into this study,
2. Diagnosis of current asthma by a health care professional,
3. Tidal breathing Provocation Concentration ≤ 16 mg/mL,
4. Forced Expiratory Volume 1> 65% of predicted,
5. No respiratory tract infection or allergen exposure ≥ 4 weeks,
6. Able to complete 2 methacholine inhalation challenges on 2 separate days at the same time of day, at least 24-h apart, and within a 2-week period,
7. Inhaled salbutamol withheld for ≥8 hours prior to testing,
8. Inhaled corticosteroid maintained at same dose throughout study,
9. inhaled formoterol and salmeterol withheld for ≥36 hours prior to testing.

Exclusion Criteria:

1. Those born prematurely (more than 4 weeks early of the calculated date),
2. Those with chronic health conditions like diabetes or cystic fibrosis,
3. Smokers.