Tissue hypoxaemia causes oedema, inflammation and fibrosis in porcine bronchial transsection

Abstract

Objectives. Bronchial artery revascularization in lung transplantation is disputed. This study examined the physiological consequences of porcine bronchial transsection and reanastomosis with and without bronchial artery blood supply with relation to lung transplantation. Design. Translational, controlled animal study. Twelve pigs were operated through a left lateral thoracotomy. The left bronchus was transsected and reanastomosed. In the control group (n = 6), the bronchial arteries were preserved and in the study group (n = 6) they were severed. Bronchial mucosa blood flow (BMBF) was measured with laser-Doppler velocimetry and bronchial mucosa haemoglobin saturation and concentration with diffuse reflectance spectrophotometry. Measurements were made preoperatively, postoperatively and after 1 week. Results. In the study group, left postoperative BMBF was significantly lower than preoperatively (115 vs. 210 PU/s, p = 0.0001) and lower than in the control group (115 vs. 205 PU/s, p = 0.002). Repeated measurement ANOVA showed a significant treatment effect depending on time (p = 0.0034). The left mucosal haemoglobin saturation in the study group was significantly reduced postoperatively, 92% versus 61%, with a treatment effect depending on time (p = 0.0080). The reduction in left/right ratio of the mucosal haemoglobin concentration 1 week postoperatively in the study group was insignificant. Conclusion. Bronchial transsection and reanastomosis without bronchial artery blood supply was followed by significant decrease in mucosal blood flow and saturation postoperatively, and also in tissue haemoglobin concentration at section, and provides a physiologic explanation of histological changes.

Key words::

• bronchial mucosal ischaemia
• bronchial pathophysiology
• animal model

Acknowledgements

This work was supported by grants from the following institutions and foundations: The Danish Medical Association Research Foundation, The Danish National Association against Lung Diseases, The Danish Hospital Foundation for Medical Research, The Beckett Fund, The Leo Research Foundation, Felo Aps, The Ib Henriksen Fund, The Dagmar Marshall Fund and the Research Fund at the Aalborg Hospital (University Hospital of Århus). Laboratory technician Karin Jensen is thanked for valuable assistance throughout the study, medical students Bettina Breitowicz and Heidi Jacobsen are thanked for operative assistance and Ph.D. Peter Snoer Jensen, Department of Optics and Fluid Dynamics, Risø, Denmark, is specially thanked for the development of programs for data acquisition.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.