The design and application of a pediatric centrifugal pump.

This centrifugal pump (CP) includes two parts: the blood pump and the driving apparatus. They are connected by six twin magnetic disc plates and driven by a magnetic DC motor (120W). The blood pump had six leaves deadlocked between two plastic discs. Six leaves were set at 30 degrees angles, separately. In the lower chamber of the CP, there was an inlay magnetic disc, which is connected with the disc leaves by an axis. This axis was sealed by silicon rubber and a ceramic ring. The priming volume of the blood chamber was 34 ml. In vitro testing showed that the free hemoglobin caused by the CP was much less than that caused by a roller pump after 180 min. The effect of this CP on blood cell damage was also studied in an animal model. Six goats were placed on cardiopulmonary bypass for 180 min. Perfusion flow rates were maintained between 1.5 and 2.5 L/min. The plasma free hemoglobin was lower in the CP group (6.04 mg/dL) than in the roller pump group (32.25 mg/dL), p < 0.01. The CP has been used in ten pediatric patients undergoing cardiopulmonary bypass surgery. The patients' ages were from three to five years, and body weights were from 15 to 20 kg. Perfusion flow rates were maintained between 1.8 and 2.5 L/min, and bypass times were from 30 to 50 min. The rotation speeds were from 2000 to 2500 rpm. All the patients recovered smoothly, and no hemoglobinuria occurred.