title: Effect of plasma expander viscosity on the cell free layer.
abstract: The effect of low and high viscosity hemodilution with plasma expanders on the extent of the cell free layer (CFL) width was analyzed in the microcirculation of the exteriorized cremaster muscle preparation of Sprague-Dawley male rats. Anesthetized animals were subjected to 40% hemodilution by blood volume, using 5% human serum albumin (HSA) or 6% Hetastarch (hydroxyethyl starch 670 kDa). Arterioles (n=5 for each treatment) were investigated. Mean arterial pressure, heart rate, vessel flow velocity and CFL width were measured at baseline and 5, 20 and 40 min post-exchange transfusion. Blood and plasma viscosity was determined from terminal blood collections. CFL width and pseudoshear rate, diameter and flow, normalized to baseline, were significantly elevated at all post-exchange assessments. Peripheral vascular resistance decreased. The increase of the CFL width was greater with HSA by comparison with Hetastarch hemodilution (p<0.05). Hetastarch blood and plasma viscosities increased significantly compared to those of HSA (p<0.05). This study shows that CFL widths are influenced by plasma expander viscosity, a phenomenon proportional to the increase in molecular weight of the colloids in solution.
authors.affiliation: Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093-0412, USA. cmhighto@ucsd.edu
authors.forename: C Makena
authors.initials: CM
authors.lastname: Hightower
authors.forename: Ozlem
authors.initials: O
authors.lastname: Yalcin
authors.forename: Beatriz Y Salazar
authors.initials: BY
authors.lastname: Vázquez
authors.forename: Paul C
authors.initials: PC
authors.lastname: Johnson
authors.forename: Marcos
authors.initials: M
authors.lastname: Intaglietta
mesh_terms: D000818:Animals; D001160:Arterioles / Q000166:cytology* / Q000187:drug effects*; D001809:Blood Viscosity / Q000187:drug effects* / Q000502:physiology; D006339:Heart Rate / Q000187:drug effects; D006438:Hemodilution; D018056:Hemorheology; D006801:Humans; D006895:Hydroxyethyl Starch Derivatives / Q000494:pharmacology; D008297:Male; D023421:Models, Animal; D010952:Plasma Substitutes / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012709:Serum Albumin / Q000494:pharmacology
chemical_list: D006895:Hydroxyethyl Starch Derivatives; D010952:Plasma Substitutes; D012709:Serum Albumin