Experimental Trial of Long-Term Heart and Lung Replacement

The feasibility of long-term total heart and lung replacement was investigated in a series of long-term animal experiments, in three adult goats and three calves. The animals’ natural heart and lungs were completely removed and replaced with an artificial heart-lung system that provided total support for both circulation and respiration. After the extirpation of the natural heart and lungs, the mean aortic pressure decreased significantly, from 96 ± 10 to 73 ± 19 mmHg. The level of prostaglandin E2, a hormone that is removed by the natural lung, increased markedly, from the pre-surgery level of 7 ± 5 pg/ml to 245 ± 273 pg/ml 2 h after the replacement. Renal dysfunction and systemic convulsions were observed in all animals, and none survived for more than 4 days postoperatively. The resection of the natural heart and lungs compromised not only the hemodynamic and metabolic condition but also major organ function, despite the well-maintained blood gas and cardiac output. Further investigation is necessary to completely elucidate the pathophysiology of total heart-lung replacement.