Increased Lung Volume as Controller Therapy for Asthma

Not Applicable

Completed

Brief Summary: This is an early phase clinical trial to test the efficacy of elevating lung volume with positive expiratory pressure (CPAP) as a controller therapy for asthma in patients with a BMI ≥ 30 kg/m2.

There will be two phases to this trial.

Phase I:

In the first phase we will determine the optimal duration of CPAP that is effective as a controller therapy in asthma. Up to 9 participants will complete this this phase.

Phase II:

The 2nd phase will be a randomized double-blinded controlled trial of Sham CPAP versus CPAP 10 (using the duration of CPAP determined in phase I) as a controller therapy for asthma, and also to determine the effect o airway reactivity in healthy people with a BMI 30 kg/m2 and above. Twenty people with asthma and twenty controls will complete this phase.

Detailed Description: The effect of 10 versus 0 cmH2O CPAP on airways responsiveness to inhaled methacholine will be studied using an adaptive "3+3" phase I/II study design.

Dose Titration Phase (phase I):

The efficacy of 8 hours of CPAP on airway responsiveness will be tested in three subjects.

Efficacy will be defined as a 25% improvement in the impedance response to methacholine in all three subjects. If this occurs in all subjects, shorter durations of CPAP will be studied (4 hours then one hour).

Conversely, if "dose escalation" is required, 3 nights, then 7 nights of CPAP will be studied.

Randomized-controlled study phase (phase II):

Participants will be randomized to CPAP 10 or Sham 0. The duration of CPAP will be determined in the dose titration phase. The effect on response to inhaled methacholine, lung function and asthma control will be determined in patients with asthma and a BMI ≥ 30 kg/m2, and also in healthy controls without asthma

Recruitment & Eligibility

Inclusion Criteria

Not provided

Exclusion Criteria

FEV1 < 60 % predicted
Other significant disease that in the opinion of the investigator would interfere with study.
Inability to perform required testing.
Smoking within last 6 months.
≥ 20 pack year smoking history
Inability to provide informed consent
Pregnancy
Known obstructive sleep apnea/ high likelihood of obstructive sleep apnea
Asthma exacerbation in the prior 6 weeks
Stoke or heart attack in the prior 3 months
Known aortic aneurysm
Renal failure
A known severe heart, vascular, liver, renal, or hematological disease
Active allergic rhinitis
Recent eye surgery (within the last month)

Arm && Interventions

Group	Intervention	Description
CPAP 10	CPAP	Participants will be randomized to CPAP 10
Sham CPAP	CPAP	Participants will be randomized to Sham CPAP

Primary Outcome Measures

Name	Time	Method
Change in impedance of lung in response to methacholine measured by forced oscillation	Through study completion, an average of one week	Average change in impedance in response to methacholine in participants assigned to Sham CPAP versus CPAP 10

Secondary Outcome Measures

Name	Time	Method
Change in spirometric lung function (FEV1 and FVC)	Through study completion, an average of one week	Average change in lung function in response to methacholine in participants assigned to Sham CPAP versus CPAP 10
Change in asthma control	Through study completion, an average of one week	Average change in asthma control in response to methacholine in participants assigned to Sham CPAP versus CPAP 10

Receive instant email notifications about changes in this clinical trial

Receive instant email notifications about changes in this clinical trial