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Journal of Veterinary Medicine
Volume 2015, Article ID 152730, 4 pages
http://dx.doi.org/10.1155/2015/152730
Research Article

Blood Density Is Nearly Equal to Water Density: A Validation Study of the Gravimetric Method of Measuring Intraoperative Blood Loss

1Department of Anesthesiology, Jesse Brown VA Medical Center, University of Illinois at Chicago, 820 S. Damen Avenue, Chicago, IL 60612, USA
2Department of General Surgery, Jesse Brown VA Medical Center, University of Illinois at Chicago, 820 S. Damen Avenue, Chicago, IL 60612, USA

Received 15 October 2014; Accepted 1 December 2014

Academic Editor: Paola Paradies

Copyright © 2015 Dominic J. Vitello et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose. The gravimetric method of weighing surgical sponges is used to quantify intraoperative blood loss. The dry mass minus the wet mass of the gauze equals the volume of blood lost. This method assumes that the density of blood is equivalent to water (1 gm/mL). This study’s purpose was to validate the assumption that the density of blood is equivalent to water and to correlate density with hematocrit. Methods. 50 µL of whole blood was weighed from eighteen rats. A distilled water control was weighed for each blood sample. The averages of the blood and water were compared utilizing a Student’s unpaired, one-tailed t-test. The masses of the blood samples and the hematocrits were compared using a linear regression. Results. The average mass of the eighteen blood samples was 0.0489 g and that of the distilled water controls was 0.0492 g. The t-test showed and . The hematocrit values ranged from 24% to 48%. The linear regression value was 0.1767. Conclusions. The value comparing the blood and distilled water masses suggests high correlation between the two populations. Linear regression showed the hematocrit was not proportional to the mass of the blood. The study confirmed that the measured density of blood is similar to water.