Development of a rabbit animal model for miniaturized heart-lung machines.

The utilization of a heart-lung machine (HLM) for the correction of congenital heart defects can lead to various complications, which can culminate in multiorgan failure and death. To reduce the considerable risk of complications, we developed a miniaturized, highly integrated HLM (MiniHLM) for use in infants and children. For the purpose of testing the MiniHLM, we developed a new rabbit animal model. In all, surgery was performed on 32 rabbits. In the first series, 13 New Zealand white rabbits were placed on cardiopulmonary bypass (CPB) for 1 hour with the use of an initial version of the MiniHLM. In the second series, we operated on 19 Chinchilla Bastard rabbits using the further developed MiniHLM 02 or the Dideco Kids D100 system. While several adjustments had to be made to the operating protocol in the first series in order to lower the mortality rate, 15 of the 19 rabbits were successfully weaned from the HLM in the second series. Blood tests pertaining to hemolysis and the expression of inflammation were performed. In addition, tissue samples were taken from the right atrial auricle for the purpose of investigating the expression of inflammatory parameters. The newly developed MiniHLM prototype was tested successfully in an animal model in terms of technical function, hemolysis, and the expression of inflammation. On account of the comparability of their blood values, as well as their anatomy, Chinchilla Bastard rabbits serve as excellent models for the testing of CPB and support systems for infants and children that do not require the administration of foreign blood.