NCT03105843

Sensory-Mechanical Responses to Eucapneic Voluntary Hyperventilation and Mannitol

Sensory-Mechanical Responses to Eucapneic Voluntary Hyperventilation and Mannitol in Individuals With Cough Variant Asthma and Chronic Cough

• Status: Recruiting
• Phase: Phase 4
• Study type: Interventional
• Enrollment: 30 (estimated)
• Sponsor: Dr. Diane Lougheed · Academic / Other
• Sex: All
• Age: 18 Years – 65 Years
• Healthy volunteers: Accepted

Summary

The objectives of this study are to determine the sensory-mechanical responses to Eucapneic Voluntary Hyperventilation (EVH) and Mannitol in individuals with cough variant asthma (CVA) and methacholine-induced cough with normal airway sensitivity (COUGH) and compare these responses to a control group of healthy individuals without asthma or chronic cough. We hypothesize: 1. EVH and Mannitol cause dyspnea, cough, small airway obstruction with resultant dynamic hyperinflation, gas trapping and autoPEEP in individuals with CVA and COUGH, but not healthy controls. 2. The sensory-mechanical responses to both hyperosmolar challenges (EVH and Mannitol) are comparable within groups (CVA, COUGH and healthy controls).

Detailed description

Asthma is a chronic respiratory condition characterized by eosinophilic airway inflammation. Individuals with classic asthma experience paroxysmal symptoms including cough, wheeze, shortness of breath and chest tightness. Cough variant asthma (CVA) is asthma in which chronic cough (cough lasting eight weeks or more) is the sole or predominant symptom of asthma. The pathophysiologic mechanisms which differentiate asthma, CVA, and eosinophilic bronchitis without asthma are not fully understood. We have recently identified individuals with chronic cough who cough during methacholine but have normal airway sensitivity (ie. do not have asthma or CVA) (COUGH) and may or may not have eosinophilic bronchitis. The purpose of this research is to further explore the pathophysiologic basis for cough in these conditions using two 'indirect' inhalation challenge tests: eucapneic voluntary hyperventilation (EVH) and Mannitol), which induce osmotic and/or temperature changes in airway. Specifically, this study will collect preliminary data on the sensory-mechanical responses of individuals with CVA, COUGH and healthy controls to EVH and Mannitol Challenges.

Conditions

• Asthma
• Cough
• Cough Variant Asthma

Interventions

Type	Name	Description
DRUG	Methacholine (MCh) Challenge Testing	Visit 1: Informed consent, Baseline screening and pulmonary function tests and Low-dose methacholine challenge testing using partial and full flow-volume loops.
DIAGNOSTIC_TEST	Eucapneic Voluntary Hyperventilation (EVH)	Visit 2 or 3: Will be conducted in random order and subjects will perform one of the two challenge tests at either visit.
DRUG	Mannitol Inhalation Kit	Visit 2 or 3: Will be conducted in random order and subjects will perform one of the two challenge tests at either visit.

Timeline

• Start date: 2022-03-01
• Primary completion: 2026-06-01
• Completion: 2026-06-30
• First posted: 2017-04-10
• Last updated: 2025-03-20

Locations

1 site across 1 country: Canada