Compared with crystalloid, colloid therapy slows progression of extrapulmonary tissue injury in septic sheep

We tested the hypothesis that the type of fluid infused to chronically maintain intravascular volumes would modify both microvascular integrity and cellular structure in extrapulmonary organs in hyperdynamic sepsis. After cecal ligation and perforation, awake sheep were treated for 48 h with 10% pentastarch (n = 9), 10% pentafraction (Du Pont Critical Care; n = 8), or Ringer lactate (n = 8) titrated to maintain a constant left atrial pressure. After 48 h of fluid therapy, biopsy samples were taken from the left ventricle and gastrocnemius for electron microscopy. At this time, all groups demonstrated a similar hyperdynamic circulatory response, increased systemic O₂ utilization and organ blood flows, measured by radioactive microsphere injection. However, greater capillary luminal areas with less endothelial swelling and less parenchymal injury were found in septic sheep treated with pentastarch vs. Ringer lactate infusion in both muscle types. Pentafraction showed few benefits in study end points over pentastarch. Thus, we conclude that chronic intravascular volume resuscitation of hyperdynamic sepsis with pentastarch ameliorated the progression of both microvascular and parenchymal injury. These findings indicate that microvascular surface area for tissue O₂ exchange in sepsis may be better preserved with chronically infused colloid, resulting in less parenchymal injury.