Effect of Prostaglandin E₂ on the Tracheobronchial Distribution of Lung Preservation Perfusate

Abstract

Complete lung preservation requires the perfusate to reach the cell it intends to protect; this is directly related to the distribution of the preserving solution throughout the lung vasculature. Several prostanoids are clinically used to enhance lung preservation. We evaluated the effect of prostaglandin E₂ (PGE₂) on the distribution of lung perfusate throughout tracheobronchial tissue, Fourteen pulmonary blocks were procured from an equal number of dogs and divided according to whether or not they had previously received a PGE₂ infusion. All lung blocks were perfused with a glucose-insulin-potassium solution, and distribution within the lung parenchyma and tracheobronchial tissue was measured using the flow reference technique and gadolinium-153-labeled microspheres. Once perfusion had taken place, samples of lung parenchyma, tracheobronchial tissue, and flow reference were measured for radioactivity, and flow was calculated per 100 g tissue. Animals receiving PGE₂ had an expected 38% decrease in systemic arterial pressure; the duration of infusion of lung perfusate during procurement was shorter in those animals receiving PGE₂ (5.75 ±.3 min, vs. no PGE₂ 8.9 ± 1.2 min; p <. 05). Perfusate flow of bronchial mucosa and cartilage increased by two to three times with the infusion of PGE₂ (p <. 01). Perfusate flow to lobar bronchus or lung parenchyma was similar in both groups. Flow within the lung parenchyma did not differ statistically when compared to its lobar distribution. In conclusion, PGE₂-treated animals had a two-to threefold increase in perfusate flow to mainstem bronchi (including mucosa); these findings to some extent support the rationale for utilizing prostanoids in order to enhance lung preservation in clinical lung transplantation.

Key Words:

• bronchial circulation
• lung preservation
• prostaglandins