Mechanistic Study of Inspiratory Training in Childhood Asthma (MICA) (MICA)

August 18, 2025 updated by: Duke University
This is single-center cross-sectional mechanistic study in lean and obese children with moderate-severe asthma, followed by a randomized, SHAM-controlled trial of Inspiratory Training (IT). The primary outcome is to describe the contributions of inspiratory muscle dysfunction (IMD) and Small Airway Dysfunction (SAD) to obesity-related versus non-obesity-related asthma. The study will involve training (IT) for 8 weeks at three intensity levels (SHAM, low and high). Target dose: 150 inspirations three times weekly. The population includes 6 to 17-year-old children with moderate to severe asthma and with a body mass index qualifying as normal habitus (BMI 5th to 84th CDC percentile) or obese habitus (≥95th percentile BMI and less than 170% of the 95th CDC percentile). Participants will be involved for 10 weeks. The investigators will use analysis of covariance (ANCOVA) to estimate and test the difference in mean values of baseline measures between obese and non-obese cohorts. Covariates will include age, sex (male/female), race/ethnicity, baseline asthma severity (NAEPP step 2 vs ≥3), and atopy status

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Cross-sectional analytic study of pulmonary mechanics comparing lean and obese children with asthma followed by a randomized, SHAM-controlled 3-arm intervention trial of inspiratory training on small airway dysfunction and inspiratory muscle function.

The central objective of the MICA (Mechanistic Study of Inspiratory Training in Childhood Asthma) study is to assess key respiratory mechanisms in 6-17 year olds with symptomatic asthma (with and without obesity) in response to IT. Our central hypothesis is that obesity promotes dyspnea and worse asthma control via inspiratory muscle fatigue/dysfunction (IMD) and small airway dysfunction (SAD), and that IT will improve inspiratory muscle function and small airway measures.

The sample size calculations and main analyses for the IT trial are designed as a traditional parallel arm intervention trial (any dose IT vs. SHAM control) with visits 1-2 serving as the baseline evaluation and the main IT endpoints being collected at the 8-week visit.

In depth phenotyping involving measures of respiratory mechanics and muscle functioning and a RCT involving inspiratory training will address these objectives.

Study Type

Interventional

Enrollment (Estimated)

76

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • United States
    • North Carolina
      • Durham, North Carolina, United States, 27704
        • Recruiting
        • Duke Healthy Lifestyles Clinic
        • Contact:
      • Durham, North Carolina, United States, 27703
        • Recruiting
        • Duke Health Center Creekstone
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • 6-17 years of age
  • Documented clinician-diagnosed asthma
  • Currently requiring 2 or more controller prescriptions to treat disease (i.e. moderate to severe persistent disease)
  • Either obese (≥95th percentile BMI and less than 170% of the 95th CDC percentile) or have a normal BMI (BMI 5th to 84th CDC percentile)

Exclusion Criteria:

  • ACT (asthma control test) score <17
  • Ever intubated for asthma
  • FEV1 < 50% of predicted at enrollment
  • Currently pregnant
  • Legal guardian unable to consent in English or Spanish
  • Any major chronic illness that, in the opinion of the PI, would interfere with participation
  • Younger than 6 years of age

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Active Low Dose inspiratory muscle rehabilitation (IMR) group
Each participant will be provided a PrO2™ device and trained on its use as well as its accompanying PrO2 Fit™ app. Participants will be instructed to inspire forcefully through PrO2™ until the device signals that the user has achieved the target resistance (via audible alarm and visible light signal). The research team will implement biofeedback signals at a specific inspiratory resistance to provide precise and individualized training target. Successful IMR repetitions will require that subjects achieve a pressure target that is 40% of their MIP (maximum inspiratory pressure).
Device: Pro2 - Low Dose - 40% of participant's MIP
Each participant will be provided a PrO2™ device and trained on its use as well as its accompanying PrO2 Fit™ app. The PrO2™ is a flow-resistive device that provides inspiratory resistance via a fixed 2mm orifice and has Bluetooth connectivity to most IOS/Android devices or Mac/Windows computers. The PrO2™ device and app allows for both 100% adherence monitoring and immediate user biofeedback. Successful IMR repetitions will require that subjects achieve a pressure target that is 40% of their MIP (maximum inspiratory pressure).
Experimental: Active High Dose inspiratory muscle rehabilitation (IMR) group
Each participant will be provided a PrO2™ device and trained on its use as well as its accompanying PrO2 Fit™ app. Participants will be instructed to inspire forcefully through PrO2™ until the device signals that the user has achieved the target resistance (via audible alarm and visible light signal). The research team will implement biofeedback signals at a specific inspiratory resistance to provide precise and individualized training target. Successful IMR repetitions will require that subjects achieve a pressure target that is 75% of their MIP (maximum inspiratory pressure).
Device: Pro2 - High Dose - 75% of participant's MIP
Each participant will be provided a PrO2™ device and trained on its use as well as its accompanying PrO2 Fit™ app. The PrO2™ is a flow-resistive device that provides inspiratory resistance via a fixed 2mm orifice and has Bluetooth connectivity to most IOS/Android devices or Mac/Windows computers. The PrO2™ device and app allows for both 100% adherence monitoring and immediate user biofeedback. Successful IMR repetitions will require that subjects achieve a pressure target that is 75% of their MIP (maximum inspiratory pressure).
Active Comparator: SHAM
Each participant will be provided a PrO2™ device and trained on its use as well as its accompanying PrO2 Fit™ app. Participants will be instructed to inspire forcefully through PrO2™ until the device signals that the user has achieved the target resistance (via audible alarm and visible light signal). The research team will implement biofeedback signals at a specific inspiratory resistance to provide precise and individualized training target. Successful IMR repetitions will require that subjects achieve a pressure target that is 15% of their MIP (maximum inspiratory pressure).
Device: Pro2 - SHAM - 15% of participant's MIP
Each participant will be provided a PrO2™ device and trained on its use as well as its accompanying PrO2 Fit™ app. The PrO2™ is a flow-resistive device that provides inspiratory resistance via a fixed 2mm orifice and has Bluetooth connectivity to most IOS/Android devices or Mac/Windows computers. The PrO2™ device and app allows for both 100% adherence monitoring and immediate user biofeedback. Successful IMR repetitions will require that participants achieve a pressure target that is 15% of their MIP (maximum inspiratory pressure).

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Number of participants with inspiratory muscle dysfunction in obesity-related versus non-obesity-related asthma
Time Frame: 10 weeks
10 weeks
Number of participants with small airway dysfunction in obesity-related versus non-obesity-related asthma
Time Frame: 10 weeks
10 weeks

Secondary Outcome Measures

Outcome Measure
Time Frame
Inspiratory muscle endurance (sustained maximal inspiratory pressure)
Time Frame: 10 weeks
10 weeks

Other Outcome Measures

Outcome Measure
Time Frame
Small airway dysfunction as measured by impulse oscillometry
Time Frame: 10 weeks
10 weeks
Small airway dysfunction as measured by residual volume
Time Frame: 10 weeks
10 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Duke University

Collaborators

National Institutes of Health (NIH)

Investigators

  • Principal Investigator: Jason Lang, MD, Duke University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

August 1, 2024

Primary Completion (Estimated)

October 30, 2027

Study Completion (Estimated)

October 30, 2027

Study Registration Dates

First Submitted

July 6, 2023

First Submitted That Met QC Criteria

July 6, 2023

First Posted (Actual)

July 14, 2023

Study Record Updates

Last Update Posted (Actual)

August 19, 2025

Last Update Submitted That Met QC Criteria

August 18, 2025

Last Verified

June 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • Pro00112858

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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