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Completed

NCT Number: NCT04001465

Determining Baseline Respiratory Duty Cycles in Subjects With and Without Airway Hyperresponsiveness

The study investigates the inspiratory duty cycle in subjects with and without airway hyper-responsiveness both at rest and during a bronchoprovocation challenge. The primary goal is to determine an average inspiratory duty cycle for standard use in the calculation of bronchoprovocation test results.

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Key information

Conditions

Airway Hyper Responsiveness Hypersensitivity Hypersensitivity, Immediate Immune System Diseases Respiratory Hypersensitivity Respiratory Tract Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Asthma Research Lab - University of Saskatchewan

Saskatoon, Saskatchewan, S7N 0W8, Canada

About this study

At least fifteen subjects with airway hyper-responsiveness and fifteen without airway hyper-responsiveness will be recruited to participate in this randomized, crossover study. Subjects will complete 2 methacholine challenges at least 24 hours apart. One methacholine challenge will entail the volumetric method using a vibrating mesh nebulizer. The second methacholine challenge will be performed identically except that the nebulizer will be fitted onto an ultrasonic nebulizer so as to measure the inspiratory duty cycle throughout the bronchoprovocation challenge.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Must be 18 years of age or older
  • Participants with airway hyper-responsiveness must have a positive methacholine challenge
  • Forced expiratory volume (FEV1) of at least 65% of predicted (based on age, height, and gender)
  • Participants without airway hyper-responsiveness must have a negative methacholine challenge
  • All participants must avoid strenuous exercise on test days
  • No short-acting beta-2 agonist use within 6 hours of study visit

Exclusion criteria

  • Participants without known airway hyper-responsiveness cannot have a current or historical respiratory condition (e.g. asthma, allergic rhinitis)
  • Participants cannot be taking long-acting bronchodilators
  • Participants cannot be pregnant or lactating
  • Participants cannot have cardiovascular problems

Treatment and study plan

Volumetric methacholine challenge unmodified

Procedure

Bronchoprovocation challenge performed per volumetric method

Modified volumetric methacholine challenge

Procedure

Bronchoprovocation challenge performed per volumetric method modified to include use of ultrasonic spirometer fitted with vibrating mesh nebulizer

Primary outcomes

  1. Average inspiratory duty cycle in subjects with airway hyper-responsiveness measured using ultrasonic spirometer and tidal breathing

    Time frame: 24 hours

    The inspiratory duty cycles measured for each participant (in duplicate over at least 24 hours) will be averaged for all participants with airway hyper-responsiveness and for all participants without airway-hyperresponsiveness

  2. Average inspiratory duty cycle in subjects without airway hyper-responsiveness

    Time frame: 24 hours

    The inspiratory duty cycles measured for each participant (in duplicate over at least 24 hours) will be averaged for all participants without airway hyper-responsiveness

Secondary outcomes

  1. Within-subject variability in inspiratory duty cycle measured using ultrasonic spirometer and tidal breathing during room air inhalation

    Time frame: 24 hours

    Repeat measurements of inspiratory duty cycle during tidal breathing of room air collected at least 24 hours apart

  2. Between-subject variability within subject group (i.e. airway hyper-responsiveness group)

    Time frame: 1 hour

    Investigation of whether subjects differ in their inspiratory duty cycles (within their respective study group)

  3. Variability in inspiratory duty cycle within subjects when inhaling room air versus an aerosol while using tidal breathing through an ultrasonic spirometer

    Time frame: 1 hour

    Investigation of whether participants differ in their inspiratory duty cycle when inhaling room air versus a saline vapor (i.e. does an aerosol influence people's breathing pattern)

  4. Within-subject variability in provocative dose of methacholine causing a 20% fall in forced expiratory volume (PD20) between repeat methacholine challenges

    Time frame: 24 hours

    Repeat PD20 measures collected for each participant will be compared to determine if there is any significant within-subject variability in PD20

  5. Variability in inspiratory duty cycle with progressive airway constriction induced through methacholine challenge testing

    Time frame: 24 hours

    The inspiratory duty cycle in each subject will be measured throughout a methacholine challenge during each inhalation period, which will allow for determination of whether the inspiratory duty cycle changes with the progressive airway constriction (or lack thereof) induced through methacholine challenge testing

  6. Variability in in inspiratory duty cycle between airway hyper-responsiveness group and group without airway-hyperresponsiveness

    Time frame: 1 hour

    Analysis of variance to determine whether subjects differ in their inspiratory duty cycles based on their status as having or as not having airway-hyperresponsiveness

  7. Within-subject variability in inspiratory duty cycle measured using ultrasonic spirometer and tidal breathing during saline inhalation

    Time frame: 24 hours

    Repeat measurements of inspiratory duty cycle during tidal breathing of nebulized saline collected at least 24 hours apart

  8. Between-subject variability within subject group (no airway hyper-responsiveness group)

    Time frame: 1 hour

    Investigation of whether subjects differ in their inspiratory duty cycles (within their respective study group)

Sponsors and collaborators

Lead sponsor

University of Saskatchewan

Other

Registry information

Important dates

Study start
2019
Primary completion
2019
Study completion
2019
First posted
Jun 28, 2019
Registry last updated
Mar 27, 2020

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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