ObjectiveThe aim of this study was to assess the relative efficacy of 2 volume replacement therapies in a canine model of induced hemorrhagic shock. MethodsAnesthetized dogs were bled to maintain mean arterial pressure (mAP) at 50 mm Hg for 30 minutes and then administered a single bolus injection of 6% hydroxyethyl starch (HES) with a molecular weight of 70 kd (HES70 group) or 200 kd (HES200 group) at a volume equivalent to the blood withdrawn. We examined the efficacy of both therapies in maintaining hemodynamic variables and splanchnic organ blood flow (ie, blood flow through the renal cortex, renal medulla, liver, and pancreas). ResultsAfter resuscitation, hemodynamic variables were better maintained in the HES200 group than in the HES70 group. In particular, HES200 better preserved mAP, cardiac index, mean pulmonary arterial pressure, pulmonary arterial wedge pressure, left ventricular stroke work index, and maximum rate of left ventricular pressure change. In both groups splanchnic organ blood flows decreased significantly after hemorrhagic shock but increased after volume replacement resuscitation. After resuscitation splanchnic organ blood flow was significantly greater in the HES200 group than in the HES70 group (P< 0.05). ConclusionsThe results of this study suggest that HES200 is more effective than HES70 as volume replacement therapy in a canine model of hemorrhagic shock, as measured by improvements in hemodynamic variables and splanchnic organ blood flow.