Effects of 24-Hour Hypothermic Storage on Isolated-Perfused Canine Heart-Lungs

Abstract

Isolated-perfused canine heart-lungs were used as a model to measure the effects of 24-hour hypothermic storage on cardiopulmonary function and metabolism. Heart-lungs were stored at 4–7°C in Euro-Collins solution (n = 6) or TP-V (n = 6). a hyperosmolar colloid solution containing dextrose, sucrose. ATP and MgCl₂. Lung inflation was maintained with 100% nitrogen. Following preservation, the heart-lungs were perfused with an albumin-mannitol perfusate for three hours at 37°C. for functional and laboratory determinations. Cold storage with TP-V soiution resulted in significantly lower enzyme activity for CPK (p < 0·0005) and LDH (p < 0·01) at 0, 1, and 3 hours of normothermic isolated perfusion. A significant reduction in lactate production (p < 0·001) was also seen in the heart-lungs stored in TP-V. No apparent differences were seen in the pH, PCO₂. and PO₂ among the two groups, nor were there any significant haemodynamic changes. Histological specimens revealed that TP-V was less damaging to both cardiac and pulmonary tissue, as only moderate oedema and congestion was apparent. These results indicate that 24 hour hypothermic storage with TP-V may be a more appropriate preservation solution for canine heart-lungs.