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Stability in lobar ventilation distribution during change in thoracic configuration
Journal of Applied Physiology
|September 1, 1975
Summary
This study shows that despite different chest movements, bilateral electrophrenic respiration (BEPR) and positive pressure-assisted ventilation (PPAV) maintain stable lobar ventilation. Lobar interdependence is key to this respiratory stability.
Area of Science:
- Respiratory Physiology
- Pulmonary Mechanics
Background:
- Understanding lobar ventilation stability is crucial for respiratory support.
- Previous research has not fully elucidated the mechanisms of lobar ventilation during different assisted breathing methods.
Purpose of the Study:
- To compare lobar ventilation stability between bilateral electrophrenic respiration (BEPR) and positive pressure-assisted ventilation (PPAV) in dogs.
- To investigate the role of lobar interdependence in maintaining upper lobe ventilation during BEPR.
Main Methods:
- Dogs were subjected to BEPR and PPAV with monitored upper lobe ventilation (VA), dead space (VD), and VD/VT ratio using the Bohr equation.
- Chest dimensions were measured via X-ray, and tantalum bronchography assessed upper lobe movement during BEPR.
Main Results:
- Despite differing thoracic dimensional changes between BEPR and PPAV, alveolar minute ventilation (VA), dead space (VD), and VD/VT ratio were comparable when tidal volume and respiratory frequency were matched.
- BEPR maintained upper lobe ventilation stability through caudal displacement, overcoming rib cage compression.
- Lobar interdependence was identified as the mechanism transmitting diaphragmatic negative pleural pressure to upper lobes.
Conclusions:
- Both BEPR and PPAV can achieve comparable lobar ventilation stability.
- Lobar interdependence plays a significant role in maintaining upper lobe ventilation during diaphragmatic breathing, even with external chest wall constraints.