Cardiorespiratory function and pathological findings in heart-lung block reimplanted after hypothermic preservation.

A good result from the heart-lung transplantation depends on the quality of the preservation of cardiopulmonary transplants. To determine the functional and pathological status of the heart-lung block after preservation for several hours, we performed 10 heterologous heart-lung transplantations in Beagle dogs (weight 13.5 kg) under extracorporeal circulation. Weight and length compatibility between donor and receiver was ensured. Measurements of hemodynamics, lung mechanics and blood gases were performed in the donor and in the receiver before the transplantation, and in the receiver after heart-lung reimplantation. Histological studies were carried out by biopsy on the heart and on the lung of the donor before removal, at the beginning of the preservation at low temperature, after 3 h of ischemia in cold, and every hour after recirculation in the heart-lung block. Myocardial preservation was conducted with cold cardioplegia at 4 degrees C (Ringer lactate solution with high potassium). Lung preservation was achieved by injecting a Euro-Collins solution at 4 degrees C, with addition of dog plasma, into the pulmonary artery; during the whole ischemic phase, the lung parenchyma was maintained at 0 degrees C, and inflated at a 10 cm H2O pressure. After transplantation, we observed that cardiac output was low in all cases, with normal or subnormal pulmonary arterial pressure. Dynamic lung compliance was very low immediately after transplantation, and increased when restarting the circulation, but deteriorated again after several hours. At the same time alveolo-arterial O2 pressure difference and arterio-alveolar CO2 pressure difference progressively increased, due to the extensive gas exchange impairment.(ABSTRACT TRUNCATED AT 250 WORDS)