Development and validation of a mathematical algorithm for quantifying preoperative blood volume by means of the decrease in hematocrit resulting from acute normovolemic hemodilution

Abstract

The changes in HK(LV) determined during ANH provide a good "bedside" estimation of preoperative BV.

A Theoretical Mathematical Model to Estimate Blood Volume in Clinical Practice

“…The CF described here measures the ratio of change in the HcT between two distinct time points (HcT b /HcT 2 ), where the difference in the measure between the time points is induced with the administration of a FB of known volume. Our methodology and results are consistent with the works published by Jacob et al (2005) and Trowbridge et al (2008). As noted by Takanishi et al (2008), single HcT measurements are clinically imprecise at predicting PV and RCV.…”

“…ANH is commonly performed by removing 1-3 units of blood (approximately 500-1,500 ml), which is then replaced with a colloid or crystalloid solution. While the efficacy of ANH as a means to reduce transfusion requirements in the perioperative setting is questionable (Segal et al, 2004), the effect of the dilution of the TBV on the HcT value has been used by some authors to estimate TBV in perioperative patients (Jacob et al, 2005). Jacob et al (2005) explored the utility of using ANH to estimate perioperative TBV.…”

State of the art in fluid and volume therapy

“…Fig. 3, in the incidence of bleeding and normovolemic dilution with infusion solutions, Hct decreases logarithmically [75]. Owing to the simpler mathematics, the calculation of blood loss presented above is not logarithmic, but rather linear.…”

Blood volume is normal after pre‐operative overnight fasting

“…Determination of PV with indocyanine green (ICG). PV was determined by diluting ICG using the whole‐blood method, as described elsewhere (14–16, 23). In brief, after calibration of the system we injected a bolus of the dye via a central venous line.…”