Ventilatory Responses to Hypercapnic and Hypoxic Conditions in Hyperventilants

NCT05189158 | Completed

• 1 other identifier: B076201836758 -2
• Study Type: interventional
• Target: 24
• Locations: 1 country
• Sites: 1

Brief Summary

For almost a century, many hypotheses have converged on the idea of altered chemosensitivity in patients suffering from hyperventilation syndrome (HVS). Given the evolution of current technical equipment and the ability to maximise true positives in HVS ( using the revised hyperventilation provocation test), it seems reasonable to investigate central and peripheral chemosensitivities in HVS subjects.

Conditions

Hyperventilation Syndrome; Hypercapnia; Hypoxia

Outcome Measures

Primary Outcomes (4)

• The slope of the ventilatory response to hypercapnia (HCVR)

  Ventilation increase (litres/min) per unit increase in PetCO2 (mmHg) using Read's method

  baseline - during the test

• The slope of the ventilatory response to hypoxia (HOVR)

  Ventilation increase (litres/min) per unit decrease in SpO2 (%) using Read's method

  baseline - during the test

• Ventilatory recruitment threshold (VRT) of the HCVR

  From the average baseline ventilation and PetCO2, the VRT id the PetCO2 level at which the ventilatory response is activated

  baseline - during the test

• Ventilatory recruitment threshold (VRT) of the HOVR

  From the average baseline ventilation and SpO2, the VRT is the level of SpO2 at which the ventilatory response is activated

  baseline - during the test

Secondary Outcomes (2)

• Extrapolated apnoeic threshold of the HCVR

  baseline - during the test

• Dyspnea

  baseline, end of the test

Study Arms (2)

HVS-

OTHER

subjects with no complaint AND a Nijmegen questionnaire score of \< 23/64 AND a negative hyperventilation provocation test (criteria revised in 2021) (HVS-)

Diagnostic Test: Hypercapnic hyperoxic ventilatory response; Diagnostic Test: Hypoxic eucapnic ventilatory response

HVS+

OTHER

subjects with complaints AND a Nijmegen questionnaire score of ≥23/64 AND a negative hyperventilation provocation test (criteria revised in 2021) (HVS+)

Diagnostic Test: Hypercapnic hyperoxic ventilatory response; Diagnostic Test: Hypoxic eucapnic ventilatory response

Interventions

Hypercapnic hyperoxic ventilatory response DIAGNOSTIC_TEST

The hypercapnic ventilatory response (HCVR) described by Read in 1967 (Read's rebreathing method) is a clinical way to assess the central and peripheric sensitivity to CO2, using a small bag (4-6 l) to achieve prompt equilibrium between the apparatus compartments and the lungs. By rebreathing a hyperoxic mixture with an initial composition of 70% O2, 7% CO2 and 23% N2, this equilibrium is assumed to be achieved after 15 seconds of rebreathing, when the relationship between VE and PetCO2 has become linear.

HVS+; HVS-

Hypoxic eucapnic ventilatory response DIAGNOSTIC_TEST

The hypoxic eucapnic ventilatory response (HOVR) is a clinical way to assess the peripheric chemosensitivity to O2, using a small bag (4-6 l) to rebreathe a gas mixture initially composed of 20% O2, 0% CO2 and Δ% N2. Eucapnia is achieved by the activation of a CO2 reabsorption cell during the course of the test.

HVS+; HVS-

Eligibility Criteria

• Age: 18 Years - 99 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• A plethysmography within subject's predicted values
• A negative metacholine test (no documented allergy)
• A hyperventilation provocation test result that is consistent with the Nijmegen questionnaire score, confirming either group classification (HVS+ or HVS-)

You may not qualify if:

• Each of the following known or documented conditions: chronic bronchitis (COPD), emphysema, asthma, cardiac disorder, neurological disorder, gastrointestinal disorder, thyroid disorder or psychological/psychiatric disorder
• Suspicious cardio-pulmonary exercise testing (CPET) with cardiac or respiratory limitation
• Pregnant women or women in the process of becoming pregnant
• Persons with a diving practice (amateur or professional),
• High-level athletes,
• Active smokers and
• persons using morphine, and/or barbiturates, and/or anxiolytics and/or sleeping pills

Sponsors & Collaborators

• Centre Hospitalier Universitaire Saint Pierre: lead
• Université Libre de Bruxelles: collaborator

Study Sites (1)

CHU St Pierre

Brussels, Brabant, 1000, Belgium

Location

MeSH Terms

Conditions

Hypercapnia; Hypoxia

Condition Hierarchy (Ancestors)

Signs and Symptoms, Respiratory; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: DIAGNOSTIC
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: October 18, 2021
• First Posted: January 12, 2022
• Study Start: October 15, 2021
• Primary Completion: October 15, 2021
• Study Completion: October 15, 2021
• Last Updated: January 12, 2022

Record last verified: 2021-12

Data Sharing

• IPD Sharing: Will not share

Locations

BE (1)