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Relationships between abdominal and diaphragmatic volume displacements
H Knight1, W M Petroll, D F Rochester
1Department of Medicine, University of Virginia, School of Medicine, Charlottesville, Virginia 22908.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|August 1, 1991
Summary
Diaphragmatic volume displacement (Vdi) exceeded abdominal wall displacement (Vabd) in dogs. The chest wall
Area of Science:
- Respiratory Physiology
- Biomechanics
Background:
- Understanding diaphragm and abdominal wall mechanics is crucial for respiratory physiology.
- The interplay between diaphragmatic and abdominal volume displacement during breathing is not fully elucidated.
Purpose of the Study:
- To investigate the relationship between diaphragmatic volume displacement (Vdi) and abdominal wall volume displacement (Vabd) during spontaneous breathing.
- To determine how chest wall and abdominal compliance influence this relationship.
Main Methods:
- Measurements were taken in supine anesthetized dogs.
- Diaphragmatic volume displacement (Vdi) calculated using fluoroscopic images and a geometric model.
- Abdominal wall volume displacement (Vabd) measured with a calibrated Respitrace.
- Diaphragm muscle bundle shortening measured using radiopaque beads.
Main Results:
- Vdi consistently exceeded Vabd.
- The ratio Vabd/Vdi increased with greater abdominal wall compliance.
- Vdi correlated better with costal than crural diaphragm shortening.
- The difference between Vdi and Vabd, reflecting lower rib cage displacement, correlated strongly with costal shortening.
Conclusions:
- Coupling between Vdi and Vabd is influenced by relative chest wall and abdominal compliances.
- Costal diaphragm shortening is closely linked to lower rib cage expansion.
- Regional diaphragm shortening may not directly correlate with overall volume displacement.