TITLE: RAPID INFUSION OF ROOM TEMPERATURE CRYSTALLOID SOLUTIONS DOES NOT RESULT IN PEAK-PLATEAU BLOOD VOLUME EXPANSION (BVE)

AUTHORS: Kirk Brauer, MD, Donald Prough, MD, Lillian Traber, RN, Dan Traber, PhD
AFFILIATION: UTMB, Galveston, Galveston, TX.

INTRODUCTION: Replacement of blood loss with crystalloid solutions conventionally is calculated as a 3:1 ratio to the hemorrhaged volume¹. Existing blood volume changes after crystalloid infusion are described in terms of non-redistributing kinetic models as a peak followed by a plateau. We measured BVE after rapid, large crystalloid fluid infusion in sheep to determine the ensuing fluid distribution kinetics.
MODEL: After a 5-day post-preparation recovery period, splenectomized, chronically instrumented, conscious adult female merino sheep (n=6; 36±3Kg) were subjected to three 3-hr protocols in random order: (1) 1L infusion of 0.9% saline over 15 min; (2) 300mL arterial blood hemorrhage over 5 min; and (3) 300mL arterial blood hemorrhage over 5 min, then 1L 0.9% saline over 15 min. Infusions were at room temperature. At least 24 hrs elapsed between protocols. Blood was returned at the conclusion of the second and third protocols. The kinetics of BVE were analyzed form changes in blood hemoglobin concentration. Data were compared via repeated measures analysis of variance, P<0.05 considered significant. Data are mean±std.
RESULTS: BVE peaked at the end of infusion, and was signifi- cantly greater with antecedent hemorrhage (3) compared to that without (1) (23±4% and 13±4%, respectively). 25 min after infusion, BVE was significantly lower than at the end of infusion in both protocols (11±2% (3) and 2±3% (1)). 60 min after infusion, BVE was still lower than that at the end of infusion, but was significantly greater than that 25 min after infusion and remained so for the remaining of the experiment (15±2% (3) and 5±3% (1)). After hemorrhage alone, BVE increased steadily (9±2%).
CONCLUSION: Antecedent hemorrhage increases apparent BVE after crystalloid infusion. Our data indicate that rapid infusion of room temperature crystalloid solutions results in a peak-trough-plateau BVE pattern, and thus that a period of rapid fluid redistribution takes place prior to the attainment of a steady BVE after infusion.
REFERENCES:

1. Anesthesia, Miller (4^thed.), Livingston, NY,1595-1617, 1994; 2. Stahle L, Nilsson A, Hahn RG: Modeling the volume of expandable body fluids during i.v. fluid therapy. Br J Anaesth 1997; 78: 138-43.