Importance of the Infusion Rate for the Plasma Expanding Effect of 5% Albumin, 6% HES 130/0.4, 4% Gelatin, and 0.9% NaCl in the Septic Rat.

OBJECTIVES:: To compare the plasma volume (PV) expanding effect of a fast infusion rate with that of a slow infusion rate of a fixed volume of 5% albumin, of the synthetic colloids, 6% hydroxyethyl starch 130/0.4 and 4% gelatin, and of 0.9% NaCl in a rat sepsis model and to compare the plasma-expanding effect among these fluids. DESIGN:: Prospective, randomized animal study. SETTING:: University hospital laboratory. SUBJECTS:: One hundred and twelve adult male rats. INTERVENTIONS:: Sepsis was induced by cecal ligation and incision followed by closure of the abdomen. After 3 hrs, an infusion of the PV expander under study was started at a volume of 12 mL/kg for the colloids and of 48 mL/kg for 0.9% NaCl, either for 15 mins or for 3 hrs. A control group underwent the same experimental procedure but no fluid was given. MEASUREMENTS AND MAIN RESULTS:: Three hours after start of the infusion (end of experiment), the plasma-expanding effect was better with a slow than a fast infusion rate for the colloids, especially albumin, but the NaCl groups did not differ significantly from the control group. The PV for the control group was 28.7 ± 3 mL/kg. In the slow and the fast infusion groups, it was 38.9 ± 4.3 and 32.6 ± 4.2 mL/kg for albumin (p < 0.001), 32.9 ± 4.3 and 29.5 ± 4.4 mL/kg for hydroxyethyl starch 130/0.4 (p < 0.05), 31.8 ± 3.9 and 28.2 ± 4.1 mL/kg for gelatin (p < 0.05), and 31.8 ± 5.3 and 30.7 ± 6.6 mL/kg for NaCl (n.s), respectively. CONCLUSIONS:: The study showed that the PV expansion by a colloid was greater when given at a slow than at a fast infusion rate, an effect more pronounced for albumin. This difference was not seen for NaCl. The PV-expanding effect was poor for NaCl and better for albumin than for the other colloids