When a patient undergoes major surgery, intravenous fluid therapy, or fluid replacement, is a critical part of the intraoperative care to optimize a patient’s blood volume, flow and oxygenation of the tissues. The current “gold standard” method to determine a patient’s total blood volume requires an injection of a radioactive tracer and serial blood sampling and is only suitable for laboratory use. 

Unfortunately, the gold standard method isn’t conducive for military practitioners to use in the battle field trauma surgical setting. Therefore, the military is interested in a simpler blood volume method that does not rely on sophisticated technology.

Charles “Chuck” Vacchiano, PhD, CRNA, FAAN, professor for Duke University School of Nursing (DUSON) and site principal investigator, received funding from the TriService Nursing Research Program to evaluate a mathematical method to calculate a patient’s total blood volume during a surgical procedure in the battle field surgical setting.

 “My colleagues and I developed a theoretical mathematical model to estimate blood volume in humans in the clinical setting in 2015,” said Vacchiano. “This funding provides a means to test the ability of the mathematical model to accurately estimate blood volume by a head-to-head comparison with the gold standard radioactive tracer method in human subjects.”

Vacchiano’s calculation requires measurement of a patient’s red blood cell concentration with a device that can be used in the field before and after giving a small volume of intravenous fluid. The dilution of the red blood cell concentration is a fundamental factor in the calculation method.

Vacchiano and his team will complete the comparison of methods in a group of volunteer subjects to determine its usefulness in the battle field setting.

Commander Ken Wofford, PhD ’12, consulting associate for DUSON, serves as the study principal investor. Wofford is an active duty U.S. Navy nurse anesthetist on the faculty of the Uniformed Services University of Health Sciences for the Daniel K. Inouye Graduate School of Nursing Nurse Anesthesia Program.

“Having a simple, reliable, accurate low-tech method to determine a patient’s blood volume in the battle field surgical setting would permit administration of IV fluids based on an objective measure associated with blood flow and tissue oxygenation,” Wofford said. “This ability could lead to reduced surgical- and anesthesia-related morbidity and mortality.”

The TriService Nursing Research Program’s mission is to facilitate nursing research to optimize the health of military members and their beneficiaries. The funding is for more than $350,000, and the study will continue until June 30, 2018.