Hager J, Koller J, Gschnitzer F, Fitz A, Klima G, Brandstaetter F. Considerations and problems in the development of the mini-spindle pump.
Artif Organs 1995;
19:660-4. [PMID:
8572969 DOI:
10.1111/j.1525-1594.1995.tb02398.x]
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Abstract
The premise for the development of the mini-spindle pump, planned as an implantable device for assisted circulation, was to transport 4 L of water/min in mock circulation with a speed of 12-15,000 rpm against an afterload of 90 mm Hg. After calculations, the resulting first prototype had a spindle rotor with 3 threads (outer diameter, 18 mm; inner diameter, 6.2 mm; length, 45 mm) in a U-shaped housing, driven by an electric motor with a cooling system. In mock circulation, this pump moved 7.8 L of water/min at 18,000 rpm. To avoid animal experiments, its influence on the blood was tested in a Maxima oxygenator. The device circulated 4.2 L of blood/min with the same speed. Because of its high traumatic hemolysis rate (> 250 mg% of free hemoglobin after 7 h of pumping), the rotor was modified, first without effect at 2.5 threads and then at 4 threads. In addition, in this third prototype, the flow direction was reversed. This prototype was more effective (4.3 L of blood/min at 12,000 rpm in the oxygenator) and the hemolysis rate, after a pumping duration of 8 h, could only be reduced to 180 mg% of free hemoglobin. As a result, a fourth prototype was developed (i.e., the U-shape of the housing was abandoned). This device functioned better than the third prototype (4.5 L of blood/min at 12,000 rpm in the oxygenator), but the blood trauma increased (220 mg% of free hemoglobin after 7 h of pumping).(ABSTRACT TRUNCATED AT 250 WORDS)
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