Pilot Validation of a Hemodilution Technique to Estimate Blood Volume in Vivo

The BVA-100 measures the hematocrit and residual plasma radioactivity of each sample in a semi-automated process, and the residual radioactivity is compared from that of the pre-injection sample to determine plasma volume. The plasma volume and BVA-100-measured hematocrit are then used to calculate the red cell volume and actual blood volume. The BVA-100 is FDA approved for blood volume measurement in vivo, has a reported precision of ± 2.5%, and has demonstrated accuracy and specificity in blood volume assessment in clinical and research settings (Van, P.Y., et al., 2011, Borovka, M., et al., 2013).

Hemodilution uses the ideal blood volume and serial hematocrit measures drawn before and after administration of a known quantity of IV fluid to estimate blood volume. Ideal blood volume is calculated using the methods described by Feldschuh and colleagues (Feldschuh, J. and Y. Enson, 1977; Feldschuh, J. and S. Katz, 2007). Hematocrit is measured using the Abbot iSTAT point of care testing device and the lab. Urine output is measured in ml. The ideal blood volume, pre and post-bolus hematocrit, fluid bolus volume, and urine output will be used to calculate estimated blood volume using a mathematical model previously described by the investigators (D'Angelo, M., et al., 2015).