Systemic and Microcirulatory Responses to Hemorrhage and Resuscitation with Fluids Containing Drag Reducing Polymers

Over the past century, resuscitation of victims of hemorrhage with crystalloid or colloid solutions has proven time and again to enhance survival. Recent animal studies have shown even further improvement if drag reducing polymers (DRPs) were added in nanomolar concentrations to these resuscitation fluids. Nevertheless, our fundamental understanding of how the microcirculation responds to hemorrhage is incomplete, as well as how properties of resuscitation fluids may modulate microvascular blood flow and tissue oxygen delivery. In the present study, we examined the systemic and microcirculatory responses to hemorrhage, as they relate to hemodynamics and oxygenation, and how resuscitation fluids modify these responses. Fourteen anesthetized, male Sprague-Dawley rats were subjected to a volume hemorrhage that reduced their blood volume by 30%. After 30 minutes of hemorrhagic hypotension, the animals were resuscitated either with a conventional colloid solution of Hespan (6% hetastarch), or Hespan plus 10 parts per million of the drag reducing polymer polyethylene oxide. A volume of either fluid equal to the shed blood volume was infused over a period of one hour. All the animals were observed for two hours following the initiation of fluid resuscitation or until they expired, with measurements made at 30-minute intervals during this time. Unlike previous studies, this study found no significant improvement in blood flow and tissue oxygenation, and no significant difference between the Control and DRP groups