Advantages of a narrow-range, medium molecular weight hydroxyethyl starch for volume maintenance in a porcine model of fecal peritonitis.

Abstract

To compare the effectiveness of two hydroxyethyl starch solutions of different molecular weight ranges for volume maintenance in a porcine model of fecal peritonitis. Randomized prospective trial. Laboratory investigation. Adolescent female pigs weighing approximately 30 kg. We compared diafiltered 6% pentastarch with 6% high molecular weight hetastarch for volume maintenance in a porcine model of fecal peritonitis. The number average molecular weight of pentastarch is higher than hetastarch, although the weight average molecular weight is lower, i.e., a narrow range of medium weight molecules. The infusion rate of each agent was adjusted to maintain baseline arterial Hct for less than or equal to 7 hr after instrumentation and induction of fecal peritonitis. The volume of fluid required to maintain arterial Hct was compared along with comparisons of hemodynamic and histologic responses associated with the two agents. Significantly less pentastarch was required to prevent hemoconcentration than hetastarch (109 +/- 22.8 vs. 150 +/- 10.3 mL/kg; p less than .05) while hemodynamics, colloid osmotic pressure, and oxygen transport responses were similar. Capillary patency was greater (21.99 +/- 3.68 vs. 10.09 +/- 1.17%; p less than .05) and mean alveolar capillary barrier thickness was less (2.36 +/- 0.13 vs. 3.06 +/- 0.17 microns; p less than .05) with pentastarch than with hetastarch, as judged by electron microscopy. These data suggest that pentastarch is better retained in the circulation in capillary leak syndromes compared with hetastarch.