Physiologic constraints in autoperfused heart-lung preservation.
The lungs usually deteriorate earlier than the heart in the autoperfused heart-lung preservation technique for transplantation; however, precise lung function during preservation has not yet been examined. The present study evaluated the physiologic changes in the autoperfused heart-lung preparation. Four dogs were tested with a conventional model, however, it was difficult to measure physiologic changes in the lungs. Seven preparations therefore were studied with a modified model in which the preload was kept constant. Stable hemodynamics could then be maintained throughout the experiment. Although pH and PaCO2 could be kept within normal range during preservation by adjusting the ventilator rate, PaO2 during 100% oxygen ventilation decreased significantly after 6 hours. Pulmonary vascular resistance increased transiently after the harvest; thereafter it normalized and remained constant for several hours but again increased markedly after 8 hours. Pulmonary compliance decreased after 7 hours. Complement activation occurred during preservation. There was a significant transpulmonary leukosequestration in the earlier phase of preservation. Platelet aggregation appeared to occur simultaneously, but counts recovered to some extent. In conclusion, autoperfused heart-lung preparation showed good viability up to 5 hours by present techniques. Lung deterioration is multifactorial and includes complement activation, trapping of leukocytes, and platelet aggregation.
D000818:Animals; D001706:Biopsy; D004285:Dogs; D006321:Heart / Q000502:physiology; D016027:Heart Transplantation; D016041:Heart-Lung Transplantation; D008168:Lung / Q000473:pathology / Q000502:physiology; D016040:Lung Transplantation; D009926:Organ Preservation / Q000295:instrumentation / Q000379:methods*; D010477:Perfusion / Q000295:instrumentation / Q000379:methods*; D014655:Vascular Resistance