Plasma substitutes for volume replacement in hemorrhagic shock: Comparisonof low and medium molecular weight hydroxyethyl starch

Objective: The aim of this study was to assess the relative efficacy of 2 v olume replacement therapies in a canine model of induced hemorrhagic shock. Methods: Anesthetized dogs were bled to maintain mean arterial pressure (mA P) at 50 mm Hg for 30 minutes and then administered a single bolus injectio n of 6% hydroxyethyl starch (HES) with a molecular weight of 70 kd (HES70 g roup) or 200 kd (HES200 group) at a volume equivalent to the blood withdraw n. We examined the efficacy of both therapies in maintaining hemodynamic va riables and splanchnic organ blood flow (ie, blood flow through the renal c ortex, renal medulla, Liver, and pancreas). Results: After resuscitation, hemodynamic variables were better maintained in the HES200 group than in the HES70 group. In particular, HES200 better p reserved mAP, cardiac index, mean pulmonary arterial pressure, pulmonary ar terial 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 bloo d flow was significantly greater in the HES200 group than in the HES70 grou p (P < 0.05). Conclusions: The results of this study suggest that HES200 is more effectiv e 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.