Abstract

Objective: To perform the compatative evaluation of a quality of lung preservation following one-time cold perfusion and developed two-time perfusion in different regimes of hypothermia.

Material and Methods: Investigations were carried out on Wistar rats of the body weight 270--330 g. Lungs were preserved by perfusion with modified Euro-Collins solution (mECS). The preservation of the lungs during 6 hours was followed by 30 minutes reperfusion with heated donor blood. In the 1st series of experiments (n = 28), we evaluated a quality of conservation after one-time cold perfusion, and after two-time perfusion with variations of perfusion tension and mECS temperature. In the 2nd series (n = 28), the influence of preservation temperature on a quality of conservation was studied.

Results: After two-time perfusion, the washing off the blood was complete. There were no signs of alterations of pulmonary capillaries endothelium. After one-time cold perfusion, lungs were washing off the blood incompletely The electron microscopy revealed swelling of endotheliocytes cytoplasm, thickening of basal membrane, accumulation of sticked and alterated erythrocytes into capillary lumen. In cases of the reperfusion with blood, the lung condition was better following two-time perfusion and preservation at 10°C: arterial-venous O₂ tension difference (ΔPO₂) - 34.39 ± 2.86 mmHg; maximum blood flow rate during reperfusion (U_P.MAX) - 8.76 ± 0.42 ml/min; increase in lungs weight following perfusion (Δm) - 1.53 ± 0.15 g. Histologic analysis showed interstitial edema with mild thickening of interalveolar walls. A quality of lungs conservation was worse following one-time cold perfusion and preservation at 4°C: ΔPO₂ - 18.43 ± 1.33 mmHg; U_P.MAX - 6.54 ± 0.23 ml/min; Δm - 2.89 ± 0.19 g. Significant decrease in ΔPO₂ up to 12.03 ± 1.48 mmHg, a decrease in U_P.MAX up to 3.44 ± 0.26 ml/min, highest Δm - 3.14 ± 0.12 g were observed following lungs preservation at 20°C. Histologic analysis revealed alveolar edema with fluid transudation into alveolar lumen.

Conclusion: The two-time perfusion of lungs with mECS allows to prevent the vascular constriction and endothelial alterations during the washing lungs off blood. The method of two-time perfusion with mECS, and lungs preservation at 10°C provides the optimal preservation of lung function during 6 hours.