Dynamic Hyperinflation During Maximal Voluntary Ventilation in Healthy Subjects

Study Overview
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Brief Summary
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Maximal Voluntary Ventilation (MVV) correlates well with maximal exercise capacity and is used to assess the ventilatory function during exercise in COPD (Chronic Obstructive Pulmonary Disease) patients. Dynamic hyperinflation (DH) often occurs during MVV in COPD and is believed to be due to expiratory flow limitation. The present study is intended to assess whether DH can also occur during MVV in normal subjects without expiratory flow limitation.

Detailed Description
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Maximal voluntary ventilation (MVV) correlates well with maximal exercise capacity and is used to assess the ventilatory function during exercise in COPD (Chronic Obstructive Pulmonary Disease) patients. Dynamic hyperinflation (DH) often occurs during MVV in COPD and is believed to be due to expiratory flow limitation. The present study is intended to assess whether DH can also occur during MVV in normal subjects without expiratory flow limitation. Study design: healthy subjects with normal lung function will perform MVV at increasing breathing frequencies and maximal tidal volume, from 10 to 100 cycles per minute. Inspiratory capacity (IC) will be measured at rest and after each 12 seconds of MVV in order to detect DH. From the moment DH appeares at a given frequency, only one additional MVV at a higher breathing frequency will be conducted to confirm DH.

Official Title
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Dynamic Hyperinflation During Maximal Voluntary Ventilation in Healthy Subjects

Conditions
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Dynamic Hyperinflation

Intervention / Treatment
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* Behavioral: Healthy Subjects


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy subjects Exclusion Criteria: History of asthma, obstructive syndrome on basic lung function

Ages Eligible for Study
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Minimum Age: 40 Years
Maximum Age: 69 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: healthy subjects<br>Subjects with normal lung function between 40 and 70 years old. | Behavioral: Healthy Subjects<br>* Subjects with normal lung function performed MVV at increasing breathing frequencies and maximal tidal volume, from 10 to 100 cycles per minute. Inspiratory capacity (IC) was measured at rest and after each 12 seconds of MVV in order to detect DH. From the moment DH appeared at a given frequency, only one additional MVV at a higher breathing frequency was conducted to confirm DH.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Frequency which induces Dynamic Hyperinflation | We analyze Frequency of Maximal Voluntary Ventilation (MVV) which induces a significant decrease of the Inspiratory Capacity (IC) post MVV compared to the IC at rest. | day one | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Correlation between the frequency which induces Dynamic Hyperinflation (DH) and Forced Expiratory Volume in one second | We analyze if there is a good correlation between the frequency which induces a significant Dynamic Hyperinflation (DH) and Forced Expiratory Volume in one second | day one | 
| Correlation between the frequency which induces Dynamic Hyperinflation (DH) and Forced Vital Capacity | We analyze if there is a good correlation between the frequency which induces a significant Dynamic Hyperinflation (DH) and Forced Vital Capacity | day one | 
| Correlation between the frequency which induces Dynamic Hyperinflation (DH) and Forced Expiratory Flows at 25%, 50% and 75% of Forced Vital Capacity | We analyze if there is a good correlation between the frequency which induces a significant Dynamic Hyperinflation (DH) and Forced Expiratory Flows at 25%, 50% and 75% of Forced Vital Capacity | day one | 
| Correlation between the frequency which induces Dynamic Hyperinflation (DH) and age | We analyze if there is a good correlation between the frequency which induces a significant Dynamic Hyperinflation (DH) and age | day one | 
| Correlation between the frequency which induces Dynamic Hyperinflation (DH) and body mass index | We analyze if there is a good correlation between the frequency which induces a significant Dynamic Hyperinflation (DH) and body mass index | day one | 
| Correlation between the frequency which induces Dynamic Hyperinflation (DH) and Inspiratory Capacity at rest | We analyzed if there is a good correlation between the frequency which induces a significant Dynamic Hyperinflation (DH) and Inspiratory capacity at rest | day one | 
| Correlation between the frequency which induces Dynamic Hyperinflation (DH) and IC/FVC ratio (IC : Inspiratory Capacity at rest ; FVC : Forced Vital Capacity) | We analyze if there is a good correlation between the frequency which induces a significant Dynamic Hyperinflation (DH) and IC/FVC ratio (IC : Inspiratory Capacity at rest ; FVC : Forced Vital Capacity) | day one | 
| Comparison Maximal Voluntary Ventilation with Forced Expiratory Volume in one second multiplied by 35 | We compare Maximal Voluntary Ventilation at the different frequencies with the common predictive value of maximal ventilation obtained by multiplying Forced Expiratory Volume in one second by 35 | day one | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Dynamic hyperinflation, Maximal Voluntary Ventilation, Inspiratory capacity, healthy subjects