Experimental study of nutating centrifugal blood pump in vivo

Summary

The nutating centrifugal pump, dubbed the teaspoon pump (TS pump), was developed by Bauermeister and Affeld [1]. Later, it was improved by Akamatsu and colleagues at Kyoto University Faculty of Technology [2–4]. We have recently performed experimental studies in vivo with the TS pump, and examined its safety and efficacy. Five male sheep, weighing 48–64 kg, were used in this study. Drainage and return cannulae were inserted into the left atrium and the descending aorta, respectively. The TS pump was then driven in totally assisted circulation in first four experiments, and in partial assist (almost 50%) in the last experiment. In all cases, the entire circulation was easily maintained, and the mean arterial pressure was maintained at over 65 mmHg. Blood samples showed no remarkable abnormality concerning hemolysis; the values of free hemoglobin 48 hours after the initiation of total assist circulation were 12–13 mg/dl. Blood cell counts and total bilirubin values were within normal limits. The antithrom bogenicity of the system remained satisfactory. However, some problems were observed: (1) when ventricular fibrillation occurred while the animal was in a hypovolemic state, the drainage was found inadequate; (2) none of the sheep were able to maintain a standing position postoperatively. In order to achieve more reliable results, we need to resolve these problems.