Vocal Cord Responses During Hyperventilation in Normal Individuals and in Mild and Severe Asthmatics.

NCT05565430 | Completed

• 1 other identifier: 16151A
• Study Type: observational
• Target: 24
• Locations: 1 country
• Sites: 1

Brief Summary

The Investigators aim to:

1. 1.Study the effect of hyperventilation on the development of paradoxical vocal cord movement (PVCM) in healthy individuals and in patients with mild and severe asthma,
2. 2.Relate PVCM to airway symptoms and measurements of intra- and extra-thoracic airway hyperresponsiveness (ET-AHR),
3. 3.Evaluate the effects of inhaled anti-cholinergic agents on PVCM induced by hyperventilation.
4. 4.In health PVCM will not occur in response to hyperventilation,
5. 5.In asthma PVCM will occur in response to hyperventilation,
6. 6.Airway symptoms and ET-AHR will develop in parallel with PVCM,
7. 7.Inhaled anticholinergic agents will prevent PVCM induced by hyperventilation.

Conditions

Hyperventilation; Larynx; Asthma

Keywords

Hyperventilation; Asthma; Vocal Cords; Extra-thoracic airway hyper-responsiveness; Anti-cholinergics

Outcome Measures

Primary Outcomes (1)

• Vocal cord aperture measured using continuous laryngoscopy after hyperventilation in normal subjects and asthmatics

  For each experiment, the subject will sit in a comfortable armchair and breathe though a rubber mouthpiece and turbine pneumotachometer (Oxycon Delta, Jaeger, Wurzburg, Germany). The airflow and volume signals and that from the carbon dioxide (CO2) analyser will be displayed on a monitor and recorded. Subjects will breath through the spirometer during endoscopy to record respiratory phase for later correlation with laryngeal recording. Laryngeal movement analysis - Image stills will be taken from the continuous laryngoscopy recording, at end inspiration and end expiration. Measurement of narrowing of the laryngeal structures in relative terms during one breathing cycle, which is independent of the distance between the laryngoscope and the glottis.

  6 years

Secondary Outcomes (3)

• Lung function indices after hyperventilation in normal and asthmatic patients.

  6 years

• Role of the extra-thoracic airway hyper-responsiveness measured using bronchial provocation test to identify asthma like symptoms.

  6 years

• Vocal cord changes after anti-cholinergic inhalers and/or exercise.

  6 years

Study Arms (3)

Healthy Control

1. Acute Hyperventilation and effects on vocal cord movement. 2. Chronic Hyperventilation and effects on vocal cord movement. 3. Effects of anticholinergic medication on paradoxical vocal cord movement.

Other: Acute Hyperventilation; Other: Chronic hyperventilation; Drug: Effects of anticholinergic medication

Mild Asthmatics

1. Acute Hyperventilation and effects on vocal cord movement. 2. Chronic Hyperventilation and effects on vocal cord movement. 3. Effects of anticholinergic medication on paradoxical vocal cord movement.

Other: Acute Hyperventilation; Other: Chronic hyperventilation; Drug: Effects of anticholinergic medication

Severe Asthmatics

1. Acute Hyperventilation and effects on vocal cord movement. 2. Chronic Hyperventilation and effects on vocal cord movement. 3. Effects of anticholinergic medication on paradoxical vocal cord movement.

Other: Acute Hyperventilation; Other: Chronic hyperventilation; Drug: Effects of anticholinergic medication

Interventions

Acute Hyperventilation OTHER

Laryngoscopy to assess vocal cord function during acute hyperventilation in normal subjects and asthmatics.

Also known as: Acute Hyperventilation in normal subjects and asthmatics

Healthy Control; Mild Asthmatics; Severe Asthmatics

Chronic hyperventilation OTHER

Laryngoscopy to assess vocal cord function during acute hyperventilation in normal subjects and asthmatics.

Healthy Control; Mild Asthmatics; Severe Asthmatics

Effects of anticholinergic medication DRUG

Laryngoscopy to assess vocal cord function after administration of anticholinergic medication.

Also known as: Effects of anticholinergic medication on vocal cord movement

Healthy Control; Mild Asthmatics; Severe Asthmatics

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Healthy controls: We shall recruit 8 normal healthy subjects (Group 1). Inclusion criteria for healthy controls include age \>18 to 65 years old, non-smokers and no history of chronic respiratory symptoms. Asthmatics: We shall recruit a total of 16 patients with asthma - 8 patients with mild asthma (Group 2) and 8 patients with severe asthma (Group 3). Mild asthma will be defined as patients with forced expiratory volume in 1 second (FEV1) \>80% predicted. Severe asthma will be defined as patients with FEV1 50-60% predicted. Asthmatics will also have a forced expiratory ratio (FER) less than the lower limit of normal, indicating obstruction.

You may qualify if:

• age \>18 to 65 years old
• non-smokers
• No history of chronic respiratory symptoms.

You may not qualify if:

• Age \< 18 or \> 65, smokers or smoking history \>10 pack years
• Any history of respiratory disorders such as asthma or chronic obstructive pulmonary disease (COPD)
• Known vocal cord pathology (i.e. laryngeal cancer) or diagnosed voice condition
• Known brain or brainstem cancer
• Known head and neck cancer
• Known neurological disorders (i.e. stroke)
• Use of medications (i.e. beta-blockers or anti-cholinergic agents which may interfere with vocal cord function)
• Singers
• Pregnancy.
• The Investigators shall recruit a total of 16 patients with asthma - 8 patients with mild asthma (Group 2) and 8 patients with severe asthma (Group 3).
• Mild asthma will be defined as patients with forced expiratory volume in 1 second (FEV1) \>80% predicted.
• Severe asthma will be defined as patients with FEV1 50-60% predicted.
• Asthmatics will also have a forced expiratory ratio (FER) less than the lower limit of normal, indicating obstruction.
• age 18-65 years
• A history of asthma defined as a bronchodilator response with increase in FEV1 \>12% and 200mls or positive bronchoprovocation testing (methacholine).

Sponsors & Collaborators

• Monash Medical Centre: lead

Study Sites (1)

Monash Medical Centre

Clayton, Victoria, 3169, Australia

Location

MeSH Terms

Conditions

Hyperventilation; Laryngeal Diseases; Asthma

Condition Hierarchy (Ancestors)

Respiration Disorders; Respiratory Tract Diseases; Signs and Symptoms, Respiratory; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Otorhinolaryngologic Diseases; Bronchial Diseases; Lung Diseases, Obstructive; Lung Diseases; Respiratory Hypersensitivity; Hypersensitivity, Immediate; Hypersensitivity; Immune System Diseases

Study Officials

• Laurence Ruane, BSc

  Monash Health and Monash University

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: observational
• Observational Model: OTHER
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Respiratory Scientist

Study Record Dates

• First Submitted: May 31, 2016
• First Posted: October 4, 2022
• Study Start: June 1, 2018
• Primary Completion: February 10, 2025
• Study Completion: February 10, 2025
• Last Updated: May 8, 2025

Record last verified: 2024-10

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF, CSR
• Time Frame: 10 years
• Access Criteria: All

Locations

AU (1)