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


Name: Kenneth Wofford

Rank: CDR

Organization: Henry M. Jackson Foundation

Performance Site: Uniformed Services University of the Health Sciences, Duke University School of Nursing

Year Published: 2016

Abstract Status: Project Completed


The primary goal of perioperative fluid therapy is to optimize patient total blood volume (TBV) for a given degree of cardiac function and thereby promote adequate end organ tissue perfusion. Commonly used methods to assess perioperative TBV and manage intravenous (IV) fluids are insensitive and nonspecific for identifying TBV abnormalities.

There is strong evidence from the civilian anesthesia and surgical literature that the use of indicators of cardiac output as markers of TBV to guide fluid therapy (Goal Directed Fluid Therapy, or GDFT), leads to significantly better patient outcomes. However, current GDFT relies heavily on technology not feasible for use in the military field setting. Therefore, the primary objective of this study is to assess the accuracy of determining a patient’s TBV using military relevant point-of-care measurement of red blood cell volume (hematocrit, or HCT) before and after hemodilution with a standard IV solution. The specific aims of the proposed research are to:

  1. Determine subject total blood volume using the gold standard DAXOR Blood Volume Analyzer-100 Analysis System (Radiotracer Dilution Technique).
  2. Compute estimated subject total blood volume using venous blood hematocrit values drawn before and after an intravenous fluid bolus (Hemodilution Technique).
  3. Correlate inter-subject radiotracer dilution technique-derived total blood volume with hemodilution technique-derived total blood

We will use a prospective validation design to test the hypothesis that the TBV predicted by a simple, clinically applicable hemodilution technique will highly correlate with the TBV measured the gold standard laboratory radiotracer dilution technique. A sample of 33 male subjects will undergo repeated TBV measurement using both an iodine 131 radiotracer technique and a normal saline hemodilution technique. Blood volume estimated by the hemodilution technique will be assessed for correlation, agreement, and bias within subject against the actual blood volume determined by the radiotracer technique.

Current techniques for accurately estimating blood volume require complex equipment and extensive training. If successful, this project will provide initial validation for a simple method of estimating blood volume that could be translated into a sensitive and specific technique for assessing adequacy of resuscitation using readily available point of care testing devices at the bedside and in austere settings.


Final report is available on NTRL: https://ntrl.ntis.gov/NTRL/dashboard/searchResults/titleDetail/PB2018101...