Hydrodynamic characteristics of a membrane oxygenator: modeling of pressure-flow characteristics and their influence on apparent viscosity. (September 2015)

• Record Type: Journal Article
• Authors: Okahara, S; Tsuji, T; Ninomiya, S; Miyamoto, S; Takahashi, H; Soh, Z; Sueda, T
• Is Part Of: Perfusion. Volume 30:Number 6(2015)
• Page Start: 478
• Page End: 483
• Publication Date: 2015-09
• Subjects: cardiopulmonary bypass -- oxygenator -- blood viscosity -- pressure gradient -- pressure-flow characteristics; Perfusion (Physiology) -- Periodicals; Blood -- Circulation, Artificial -- Periodicals; Heart -- Surgery -- Periodicals; Extracorporeal Circulation -- Periodicals; Perfusion -- Periodicals; Circulation extracorporelle -- Périodiques; Perfusion -- Périodiques; 617.41
• DOI: 10.1177/0267659114562101
• Languages: English
• ISSNs: 0267-6591

Abstract

The viscosity obtained from pressure-flow characteristics of an oxygenator may help to detect factors that change oxygenator resistance. The objective of this study was to model pressure-flow characteristics of a membrane oxygenator with an integrated arterial filter and to quantify their influence on apparent viscosity of non-Newtonian fluids. One Newtonian fluid (glycerin solution) and two non-Newtonian fluids (whole bovine blood and a human red blood cell suspension) were perfused through an oxygenator and their pressure-flow characteristics examined systematically. Four resistance parameters for the pressure gradient characteristics approximation equation were obtained by the least squares method from the relational expression of pressure-flow characteristics and viscosity. For all three fluids, a non-linear flow to pressure change was observed with a coefficient of determination of almost 1 by exponential approximation. The glycerin solution had a higher pressure gradient (10-70%) than the other fluids; the apparent viscosity of the non-Newtonian fluids was around 35% lower than the static one measured by a torsional oscillation viscometer. Overall, our study demonstrated that the influence on the apparent viscosity of non-Newtonian fluids can be quantified by pressure gradient differences in a membrane oxygenator with an integrated arterial filter.