title: Centrifugal pump performance during low-flow extracorporeal CO2 removal; safety considerations.
abstract: OBJECTIVE
  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.
  
  
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Deptartment of Cardiothoracic Surgery, Maastricht University Medical Centre and Cardiovascular Research Institute Maastricht, Maastricht, the Netherlands antoinepsimons@ctc.unimaas.nl.
authors.forename: A P
authors.initials: AP
authors.lastname: Simons
authors.affiliation: Department of Clinical Neurophysiology, Maastricht University Medical Centre, Maastricht, the Netherlands.
authors.forename: E G H J
authors.initials: EG
authors.lastname: Martens
authors.affiliation: Deptartment of Cardiothoracic Surgery, Maastricht University Medical Centre and Cardiovascular Research Institute Maastricht, Maastricht, the Netherlands.
authors.forename: Y M
authors.initials: YM
authors.lastname: Ganushchak
authors.affiliation: Deptartment of Cardiothoracic Surgery, Maastricht University Medical Centre and Cardiovascular Research Institute Maastricht, Maastricht, the Netherlands.
authors.forename: P W
authors.initials: PW
authors.lastname: Weerwind
mesh_terms: D002245:Carbon Dioxide / Q000097:blood*; D002315:Cardiopulmonary Bypass / Q000295:instrumentation*; D002498:Centrifugation / Q000295:instrumentation*; D005112:Extracorporeal Circulation / Q000295:instrumentation / Q000379:methods*; D005740:Gases / Q000097:blood* / Q000302:isolation & purification*; D006801:Humans; D057446:Hydrodynamics; D007260:Infusion Pumps; D011312:Pressure; D012449:Safety
chemical_list: D005740:Gases; D002245:Carbon Dioxide
keywords: CO2 removal; centrifugal pump; degassing; extracorporeal life support; gaseous microemboli