Dynamic Hyperinflation
Conditions
Keywords
Dynamic hyperinflation, Maximal Voluntary Ventilation, Inspiratory capacity, healthy subjects
Brief summary
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
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.
Interventions
BEHAVIORALHealthy Subjects
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.
Sponsors
Centre Hospitalier Universitaire Saint Pierre
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
40 Years to 69 Years
Healthy volunteers
Yes
Inclusion criteria
* Healthy subjects
Exclusion criteria
* History of asthma, obstructive syndrome on basic lung function
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Frequency which induces Dynamic Hyperinflation | day one | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Correlation between the frequency which induces Dynamic Hyperinflation (DH) and Forced Vital Capacity | day one | We analyze if there is a good correlation between the frequency which induces a significant Dynamic Hyperinflation (DH) and Forced Vital Capacity |
| Correlation between the frequency which induces Dynamic Hyperinflation (DH) and Forced Expiratory Flows at 25%, 50% and 75% of Forced Vital Capacity | day one | 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 |
| Correlation between the frequency which induces Dynamic Hyperinflation (DH) and age | day one | We analyze if there is a good correlation between the frequency which induces a significant Dynamic Hyperinflation (DH) and age |
| Correlation between the frequency which induces Dynamic Hyperinflation (DH) and Forced Expiratory Volume in one second | day one | 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 |
| Correlation between the frequency which induces Dynamic Hyperinflation (DH) and Inspiratory Capacity at rest | day one | We analyzed if there is a good correlation between the frequency which induces a significant Dynamic Hyperinflation (DH) and Inspiratory capacity at rest |
| Correlation between the frequency which induces Dynamic Hyperinflation (DH) and IC/FVC ratio (IC : Inspiratory Capacity at rest ; FVC : Forced Vital Capacity) | day one | 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) |
| Comparison Maximal Voluntary Ventilation with Forced Expiratory Volume in one second multiplied by 35 | day one | 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 |
| Correlation between the frequency which induces Dynamic Hyperinflation (DH) and body mass index | day one | We analyze if there is a good correlation between the frequency which induces a significant Dynamic Hyperinflation (DH) and body mass index |
Countries
Belgium
Contacts
Primary ContactAudrey Herpeux
Backup ContactInge Muylle, MD
Outcome results
None listed