title: The viscous characterization of hydroxyethyl starch (HES) plasma volume expanders in a non-Newtonian blood analog.
abstract: Although information pertaining to the viscous characterization of HES 130/0.4 Voluven® and HES 260/0.45 Pentaspan® is available, quantification is limited to 100% concentrations. We focus here on the quantification of their viscous behavior along with HES 130/0.4 Volulyte® in a shear thinning non-Newtonian blood analog of aqueous xanthan gum and glycerol. Dynamic viscosities of multiple batches of HES fluids were measured through capillary viscometry. The viscous behavior of 100%, 25% and 12.5% concentrations were then measured through a closed flow loop across physiologically relevant flow rates. Measured viscosities were 2.57 millipascal second (mPa·s) 6.52 mPa·s and 2.48 mPa·s for HES 130/0.4 Voluven®, HES 260/0.45 and HES 130/0.4 Volulyte®, respectively. Pipe flow analysis found that all HES fluids displayed Newtonian behavior at 100% concentrations. 25% concentrations of both HES 130/0.4 fluids decreased analog viscosity 23%-29% at a flow rate of 1.0 ml/s and 16%-21% at a flow rate of 22.5 ml/s. At a flow rate of 22.5 ml/s, 25% and 12.5% concentrations of HES 260/0.45 resulted in analog viscosity changes of 3.9%-4.5%. Capillary viscosity reductions of approximately 7% and 14.5% in HES 130/0.4 Voluven® and HES 260/0.45 suggest changes in molecular composition to batches previously measured. Maintenance of analog viscosity suggests that HES 260/0.45 would be suitable as a high viscosity plasma expander in extreme hemodilution through preservation of microcirculatory function and wall shear stress (WSS).
authors.affiliation: Department of Mechanical and Manufacturing Engineering, University of Calgary, Calgary, AB, Canada. walkeram@ucalgary.ca
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Walker
authors.forename: Yao
authors.initials: Y
authors.lastname: Xiao
authors.forename: Clifton R
authors.initials: CR
authors.lastname: Johnston
authors.forename: David E
authors.initials: DE
authors.lastname: Rival
mesh_terms: D001783:Blood Flow Velocity; D006801:Humans; D006895:Hydroxyethyl Starch Derivatives / Q000737:chemistry*; D008833:Microcirculation; D010952:Plasma Substitutes / Q000737:chemistry*; D011135:Polysaccharides, Bacterial / Q000737:chemistry; D014783:Viscosity
chemical_list: D006895:Hydroxyethyl Starch Derivatives; D010952:Plasma Substitutes; D011135:Polysaccharides, Bacterial; C002563:xanthan gum