Peribronchial stress analysis utilizing concentric cylindrical shells of parenchyma

Area of Science:

• Pulmonary Biomechanics
• Computational Biology
• Respiratory Physiology

Background:

• Bronchial volume is influenced by lung tissue properties and pressure gradients.
• Understanding these mechanical dependencies is crucial for respiratory mechanics research.

Purpose of the Study:

• To investigate the mechanical dependence of bronchial volume on parenchymal properties and pressures.
• To analyze nonhomogeneous large deformations of lung tissue using finite elasticity theory.

Main Methods:

• Applied finite elasticity theory to model lung parenchyma as a compressible continuum.
• Used a strain-energy-density function fitted to saline-filled lung pressure-volume curves.
• Analyzed fluid-filled excised dog lobe deformations via numerical procedures, representing bronchi as thick-walled cylinders.

Main Results:

• Theoretical results aligned well with published stress and strain data for bronchial collapse.
• Peribronchial radial and circumferential stresses were concentrated at the bronchial wall.
• These stresses rapidly dissipated within 1-2 bronchial radii from the wall.

Conclusions:

• The mechanical behavior of bronchial volume is dependent on lung parenchymal properties and pressure dynamics.
• Finite elasticity theory provides a viable method for analyzing lung tissue deformations.
• Regional lung recoil around bronchi during collapse can be estimated using theoretical analysis based on lung pressure-volume relationships.