Dynamic Hyperinflation During Maximal Voluntary Ventilation in Healthy Subjects

Dynamic Hyperinflation During Maximal Voluntary Ventilation in Healthy Subjects

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.

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.

Inclusion Criteria:

• Healthy subjects

Exclusion Criteria:

• History of asthma, obstructive syndrome on basic lung function