Respiratory Function Tolerance of Rats with Vaying Degrees of Thoracic Volume Reduction

Area of Science:

• Biomedical Engineering
• Thoracic Surgery
• Respiratory Physiology

Background:

• Rib fractures can lead to thoracic collapse and reduced thoracic volume.
• The impact of varying degrees of thoracic volume reduction on respiratory function requires further investigation.
• Assessing thoracic volume as a metric for rib fracture severity is crucial for clinical management.

Purpose of the Study:

• To compare the effects of different degrees of reduced thoracic volume on respiratory function in rats.
• To evaluate the tolerance of rats with reduced thoracic volume.
• To assess the feasibility of using thoracic volume as a measure of rib fracture severity.

Main Methods:

• 24 female Sprague-Dawley rats underwent bilateral rib fractures with displacements of 2, 4, 6, and 8 mm.
• Respiratory function was measured using whole-body barometric plethysmography for 14 days post-operation.
• Chest CT scans and 3D reconstructions were used to quantify thoracic and lung volume reduction.

Main Results:

• Thoracic volume reduction ranged from 5.20% to 20.74% with increasing fracture displacement.
• Significant lung volume reduction was observed in the 8 mm group.
• Postoperative tidal volume decreased in all groups, with the 8 mm group showing the most significant reduction (1.23 ± 0.12 mL).

Conclusions:

• Displaced rib fractures cause thoracic collapse, reducing thoracic volume and affecting tidal volume.
• Thoracic volume reduction is a reliable objective parameter for evaluating the severity of multiple rib fractures.
• Early surgical intervention to restore thoracic volume may improve early respiratory function, with potential for long-term compensation and recovery.