title: Pulse conductance and flow-induced hemolysis during pulsatile cardiopulmonary bypass.
abstract: In this study, the hypothesis was tested that a low-resistant, high-compliant oxygenator provides better pulse conductance and less hemolysis than a high-resistant, low-compliant oxygenator during pulsatile cardiopulmonary bypass. Forty adults undergoing coronary artery bypass surgery were randomly divided into two groups using either an oxygenator with a relatively low hydraulic resistance (Quadrox BE-HMO 2000, Maquet Cardiopulmonary AG, Hirrlingen, Germany) or with a relatively high hydraulic resistance (Capiox SX18, Terumo Cardiovascular Systems, Tokyo, Japan). The phase shift between the flow signals measured at the inlet and outlet of the oxygenator was used to assess compliance. Pulse conductance in terms of pressure attenuation was calculated by dividing the outlet pulse pressure of the oxygenator by the inlet pulse pressure. A normalized index was used to assess hemolysis. The phase shifts in time of the flow pulses were 36 +/- 6 ms in the low-resistant (high-compliant) oxygenator, and 14 +/- 2 ms in the high-resistant (low-compliant) oxygenator group (P < 0.001). The low-resistant, high-compliant oxygenator provided 27% better pulse conductance compared with the high-resistant, low-compliant oxygenator (0.84 +/- 0.02 and 0.66 +/- 0.01, respectively, P < 0.001). Inlet pulse pressures were significantly higher (29%) in the high-resistant, low-compliant (Capiox) group than in the low-resistant, high-compliant (Quadrox) group (838 +/- 38 mm Hg and 648 +/- 25 mm Hg respectively, P < 0.001), but no significant difference in hemolysis was found. A low-resistant, high-compliant oxygenator provides better pulse conduction than a high-resistant, low-compliant oxygenator. However, the study data could not confirm the association of high pressures with increased hemolysis.
authors.affiliation: Department of Cardiothoracic Surgery and Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands. antoinepsimons@ctc.unimaas.nl
authors.forename: Antoine P
authors.initials: AP
authors.lastname: Simons
authors.forename: Pieter
authors.initials: P
authors.lastname: Wortel
authors.forename: Rob A T
authors.initials: RA
authors.lastname: van Kan
authors.forename: Frederik H
authors.initials: FH
authors.lastname: van der Veen
authors.forename: Patrick W
authors.initials: PW
authors.lastname: Weerwind
authors.forename: Jos G
authors.initials: JG
authors.lastname: Maessen
mesh_terms: D000368:Aged; D001794:Blood Pressure; D002315:Cardiopulmonary Bypass / Q000009:adverse effects* / Q000295:instrumentation*; D001026:Coronary Artery Bypass / Q000009:adverse effects* / Q000295:instrumentation*; D004867:Equipment Design; D005260:Female; D006339:Heart Rate; D006461:Hemolysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D010106:Oxygenators; D011673:Pulsatile Flow