Centrifugal pump performance during low-flow extracorporeal CO2 removal; safety considerations

• Published in: Perfusion Vol. 30; no. 1; pp. 17 - 23
• Main Authors: Simons, AP, Martens, EGHJ, Ganushchak, YM, Weerwind, PW
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.01.2015; Sage Publications Ltd
• Subjects: Carbon Dioxide - blood; Cardiopulmonary Bypass - instrumentation; Centrifugation - instrumentation; Extracorporeal Circulation - instrumentation; Extracorporeal Circulation - methods; Gases - blood; Gases - isolation & purification; Humans; Hydrodynamics; Infusion Pumps; Pressure; Safety; gaseous microemboli; extracorporeal life support; degassing; centrifugal pump; CO2 removal
• ISSN: 0267-6591; 1477-111X
• DOI: 10.1177/0267659114540024

Aim: The aim of this study was to examine the hydrodynamic performance and gaseous microemboli (GME) activity of two centrifugal pumps for possible use in low-flow extracorporeal CO2 removal. Materials & Methods: The performance of a Rotassist 2.8 and a Rotaflow 32 centrifugal pump (Maquet Cardiopulmonary AG, Hirrlingen, Germany) was evaluated in a water-glycerine mixture-filled in vitro circuit that enabled measurement of pressures and GME at the pump inlet and pump outlet. Pressure-flow curves were acquired in a 1,000 to 5,000 rpm range while increasing drainage resistance in one series and outlet resistance in another. Results: Respective minimum pump inlet and maximum pump outlet pressures were −539 mmHg and 754 mmHg for the Rotassist 2.8 and −606 mmHg and 806 mmHg for the Rotaflow 32. Maximum standard deviations on pump pressures and flow amounted to 3.0 mmHg and 0.03 L/min, respectively, regardless of pump type and drainage or outlet resistance. The GME at the pump outlet were detectable at pump inlet pressures below −156 mmHg at 0.2 L/min and 2,500 rpm for the Rotassist 2.8 and below −224 mmHg at 0.9 L/min and 3,000 rpm for the Rotaflow 32. Conclusion: Both the Rotassist 2.8 and Rotaflow 32 centrifugal pumps show a comparably high hydrodynamic stability, but potential GME formation with decreasing pump inlet pressures should be taken into account to ensure safe centrifugal pump-based low-flow extracorporeal CO2 removal.