Evaluating the Feasibility and Reliability of Using Handheld Nebulizers to Conduct Cough Sensitivity Testing With Citric Acid

May 20, 2026 updated by: University of Montana
Objective cough reflex sensitivity testing is typically restricted to specialized research laboratories due to reliance on expensive dosimeter-controlled aerosol delivery systems. This study evaluates the feasibility and reliability of a low-cost alternative method using a handheld nebulizer for citric acid cough challenge testing. Healthy adult participants will complete cough reflex sensitivity testing using both a standard dosimeter-controlled nebulizer system (Cosmed QuarkSpiro) and a handheld nebulizer (DeVilbiss 45). The study will compare cough threshold outcomes between methods to determine whether handheld nebulizer-based testing produces comparable and reproducible measurements.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Cough reflex sensitivity testing is widely used in respiratory research to quantify airway sensory responsiveness. Traditional testing protocols use dosimeter-controlled nebulizer systems to deliver precise concentrations of aerosolized tussive agents such as citric acid. However, these systems are costly and require specialized laboratory infrastructure, limiting access to objective cough testing in outpatient and community-based settings.

This study investigates the feasibility and reliability of using a commercially available handheld nebulizer as a low-cost alternative for cough reflex sensitivity testing. Healthy adult volunteers will undergo standardized cough challenge testing using citric acid delivered through two aerosol delivery systems: a laboratory dosimeter-controlled nebulizer (Cosmed QuarkSpiro) and a handheld nebulizer (DeVilbiss 45). The primary outcomes will be cough threshold measures (e.g., C2 and C5), defined as the citric acid concentration that elicits two or five coughs.

Participants will complete testing sessions using both delivery methods under controlled conditions. Findings from this proof-of-concept study will inform future research aimed at expanding access to objective cough assessment in clinical and community settings.

Study Type

Interventional

Enrollment (Estimated)

10

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 Contact Backup

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

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Healthy adults at least 18 years of age
  • Consent to audio/video recording of the research sessions for research purposes
  • Spirometry testing results obtained by study team on same day of first testing session with FEV1/FVC ratio and FEV1 percent predicted values of at least 0.70

Exclusion Criteria:

  • Pregnant or trying to become pregnant (if capable of becoming pregnant- a urine pregnancy test will be provided onsite and a negative result must be obtained prior to the first testing session)
  • Smoking of any substance in the last six months
  • Diagnosed or suspected pulmonary disease (e.g., asthma, COPD)
  • History of chronic cough
  • History of head or neck cancer
  • History of neurological disease (e.g., cerebrovascular accident)
  • History of dysphagia (swallowing difficulty)
  • Current complaint of a voice problem
  • Current upper respiratory infection

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: Diagnostic
  • Allocation: Non-Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Dosimeter-Controlled Cough Reflex Sensitivity Testing
Participants will undergo cough reflex sensitivity testing using a dosimeter-controlled nebulizer system (Cosmed QuarkSpiro) to deliver aerosolized citric acid.
Device: Cosmed QuarkSpiro Dosimeter-Controlled Nebulizer
Laboratory spirometry system equipped with a dosimeter-controlled nebulizer used to deliver standardized aerosolized citric acid during cough challenge testing.
Experimental: Handheld Nebulizer Cough Reflex Sensitivity Testing
Participants will undergo cough reflex sensitivity testing using a handheld nebulizer (DeVilbiss 45) to deliver aerosolized citric acid.
Device: DeVilbiss 45 Handheld Nebulizer
Commercial handheld nebulizer used to deliver aerosolized citric acid during cough challenge testing.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Test-retest reliability of the concentration of citric acid that elicits two or more coughs (C2)
Time Frame: Cough sensitivity testing to determine cough thresholds (C2) will be performed at each of four weekly study visits, with visits occurring every 7 days across a 4-week study period.
The test-retest reliability (Intraclass correlation coefficient) of the citric acid concentration required to elicit two coughs during cough challenge testing will be evaluated and compared for each testing method.
Cough sensitivity testing to determine cough thresholds (C2) will be performed at each of four weekly study visits, with visits occurring every 7 days across a 4-week study period.
Test-retest reliability of the concentration of citric acid that elicits five or more coughs (C5)
Time Frame: Cough sensitivity testing to determine cough thresholds (C5) will be performed at each of four weekly study visits, with visits occurring every 7 days across a 4-week study period.
The test-retest reliability (Intraclass correlation coefficient) of the citric acid concentration required to elicit five coughs during cough challenge testing will be evaluated and compared for each testing method.
Cough sensitivity testing to determine cough thresholds (C5) will be performed at each of four weekly study visits, with visits occurring every 7 days across a 4-week study period.

Collaborators and Investigators

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

Sponsor

University of Montana

Collaborators

National Institute of General Medical Sciences (NIGMS)

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 (Estimated)

May 26, 2026

Primary Completion (Estimated)

February 1, 2027

Study Completion (Estimated)

February 28, 2027

Study Registration Dates

First Submitted

March 17, 2026

First Submitted That Met QC Criteria

April 13, 2026

First Posted (Actual)

April 15, 2026

Study Record Updates

Last Update Posted (Actual)

May 26, 2026

Last Update Submitted That Met QC Criteria

May 20, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • IRB-FY2026-31
  • 2P20GM130418-06 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

De-identified individual participant data supporting the results reported in publications will be available upon reasonable request to the Principle Investigator following publication of study findings.

IPD Sharing Time Frame

IPD and supporting information will be available as soon as one month after data are published and available for up to three years after publication.

IPD Sharing Access Criteria

Data will be shared with qualified investigators who provide a methodologically sound proposal and documentation of appropriate institutional approvals, where required. Data will be shared in a de-identified format consistent with institutional policies and applicable privacy protections. Due to the small sample size, additional safeguards may be implemented to prevent potential participant re-identification.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP
  • ICF

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

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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