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Characteristics of a Blood Pump Combining the Centrifugal and Axial Pumping Principles: The Spiral Pump
Author(s) -
Andrade Aron,
Biscegli José,
Dinkhuysen Jarbas,
Sousa José Eduardo,
Ohashi Yukio,
Hemmings Sarah,
Glueck Julie,
Kawahito Koji,
Nosé Yukihiko
Publication year - 1996
Publication title -
artificial organs
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.684
H-Index - 76
eISSN - 1525-1594
pISSN - 0160-564X
DOI - 10.1111/j.1525-1594.1996.tb04489.x
Subject(s) - impeller , centrifugal pump , conical surface , volumetric flow rate , hemolysis , materials science , rotational speed , axial flow pump , ventricular assist device , progressive cavity pump , axial compressor , pressure head , reciprocating pump , spiral (railway) , mechanics , biomedical engineering , variable displacement pump , mechanical engineering , physics , composite material , engineering , cardiology , medicine , heart failure , gas compressor , immunology
Two well‐known centrifugal and axial pumping principles are used simultaneously in a new blood pump design. Inside the pump housing is a spiral impeller, a conically shaped structure with threads on the surface. The worm gears provide an axial motion of the blood column through the threads of the central cone. The rotational motion of the conical shape generates the centrifugal pumping effect and improves the efficiency of the pump without increasing hemolysis. The hydrodynamic performance of the pump was examined with a 40% glycerin‐water solution at several rotation speeds. The gap between the housing and the top of the thread is a very important factor: when the gap increases, the hydrodynamic performance decreases. To determine the optimum gap, several in vitro hemolysis tests were performed with different gaps using bovine blood in a closed circuit loop under two conditions. The first simulated condition was a left ventricular assist device (LVAD) with a flow rate of 5 L/min against a pressure head of 100 mm Hg, and the second was a cardiopulmonary bypass (CPB) simulation with a flow rate of 5 L/min against 350 mm Hg of pressure. The best hemolysis results were seen at a gap of 1.5 mm with the normalized index of hemolysis (NIH) of 0.0063 ± 0.0020 g/100 L and 0.0251 ± 0.0124 g/100 L (mean ± SD; n = 4) for LVAD and CPB conditions, respectively.