Contemporary Oxygenator Design: Shear Stress‐Related Oxygen and Carbon Dioxide Transfer

• Published in: Artificial organs 2018-06, Vol.42 (6), p.611-619
• Main Authors: Hendrix, Rik H. J., Ganushchak, Yuri M., Weerwind, Patrick W.
• Format: Article
• Language: English
• Subjects: Aortic valve; Bivariate analysis; Blood flow; Blood levels; Carbon dioxide; Carbon dioxide transfer; Cardiopulmonary bypass; Concentration gradient; Coronary artery; Correlation analysis; Data processing; Design; Fluid dynamics; Gas exchange; Gas flow; Heart surgery; Hemoglobin; Loess; Oxygen; Oxygen transfer; Oxygenator; Shear stress; Surgical apparatus & instruments; Turbulence
• ISSN: 0160-564X; 1525-1594
• DOI: 10.1111/aor.13084

Design of contemporary oxygenators requires better understanding of the influence of hydrodynamic patterns on gas exchange. A decrease in blood path width or an increase in intraoxygenator turbulence for instance, might increase gas transfer efficiency but it will increase shear stress as well. The aim of this clinical study was to examine the association between shear stress and oxygen and carbon dioxide transfer in different contemporary oxygenators during cardiopulmonary bypass (CPB). The effect of additional parameters related to gas transfer efficiency, that is, blood flow, gas flow, sweep gas oxygen fraction (FiO2), hemoglobin concentration, the amount of hemoglobin pumped through the oxygenator per minute—Qhb, and shunt fraction were contemplated as well. Data from 50 adult patients who underwent elective CPB for coronary artery bypass grafting or aortic valve replacement were retrospectively analyzed. Data included five different oxygenator types with an integrated arterial filter. Relationships were determined using Pearson bivariate correlation analysis and scatterplots with LOESS curves. In the Capiox FX25, Fusion, Inspire 8F, Paragon, and Quadrox‐i groups, mean blood flows were 4.8 ± 0.9, 5.3 ± 0.7, 4.9 ± 0.7, 5.0 ± 0.6, and 5.7 ± 0.6 L/min, respectively. The mean O2 transfer/m2 membrane surface area was 44 ± 14, 51 ± 9, 60 ± 10, 63 ± 14, and 77 ± 18, respectively, whereas the mean CO2 transfer/m2 was 26 ± 14, 60 ± 22, 73 ± 29, 74 ± 19, and 96 ± 20, respectively. Associations between oxygen transfer/m2 and shear stress differed per oxygenator, depending on oxygenator design and the level of shear stress (r = 0.249, r = 0.562, r = 0.402, r = 0.465, and r = 0.275 for Capiox FX25, Fusion, Inspire 8F, Paragon, and Quadrox‐i, respectively, P