Abstract
It was stated that when the patients with pulmonary emphysema exercised, its FRC was increased because of expiratory limitation.
We calculated the change in FRC levels during excercise by measuring the tidal inspiratory volume and tidal expiratory volume by breath by breath. The results showed FRC decrease in during exercise. The mechanism of this decrease was considered due to a specific respiratory pattern during exercise. The minute ventilation increased during exercise with the increase of both respiratory frequency and tidal volume. When the tidal volume increased, respiratory frequency decreased, and when respiratory frequency increased, the tidal volume was decreased.
Minute ventilation increased with the repeat of these respiratory pattern, and the FRC level did not increase. It was considered that when tidal volume increased, expiratory frequency was limited so that enough expiratory time was needed and expiratory time prolonged to avoid air trapping due to the decrease of respiratory frequency. When respiratory frequency increased, expiratory volume was limited so that tidal volume decreaead to avoid air trapping.
FRC in the patients with pulmonary emphysema decreased during exercise.
