Calcium Supplementation of Saline-Based Colloids Does Not Produce Equivalent Coagulation Profiles to Similarly Balanced Salt Preparations

Objectives: The primary objective of this study was to test the hypothesis that calcium alone does not account for the observed coagulation differences between saline-based and balanced electrolyte IV fluid preparations. Design: Controlled, nonblinded, in vitro observational study. Setting: University-based anesthesia research laboratory. Participants: Ten healthy volunteers. Interventions: The volunteers donated fresh blood for in vitro 40% and 60% dilution with 6 intravenous fluid preparations (lactated Ringer's solution, human albumin solution, and 4 hydroxyethyl starch preparations). All saline-based fluids were supplemented with calcium chloride to obtain ionized concentrations ≥1.0 mmol/L. Measurements and Main Results: After dilution of the fresh blood with the study fluids, samples were analyzed by using the Thrombelastograph®. Three colloid preparations produced minimal coagulation derangement, even at 60% dilution (human albumin solution, tetrastarch in saline, and pentastarch in balanced electrolyte solution), whereas pentastarch in saline and hetastarch in balanced electrolyte produced a mildly hypocoagulable state at 60% dilution. Conclusions: The different coagulation profiles between the 2 pentastarch preparations, as well as similar profiles of pentastarch in saline and hetastarch in balanced electrolyte solution, suggest that calcium is not solely responsible for previously observed effects.