Page 90 - Journal of Special Operations Medicine - Spring 2017

Clinical Image
Visual Estimation of Blood Loss

Benjamin Donham, MD; Robby Frondozo, CRNA; Michael Petro, MD;
Andrew Reynolds; Jonathan Swisher, MD; Ryan Knight, MD

ABSTRACT

Military prehospital providers frequently have to make of more advanced monitoring such as cardiac monitors
important clinical decisions with only limited objec- and manual blood pressure auscultation. Therefore,
tive information and vital signs. Because of this, ac- many prehospital providers make important clinical de-
curate estimation of blood loss, at the point of injury, cisions based on limited vital signs.
can augment any available objective information. Prior
studies have shown that individuals significantly over- Visual Estimation of Blood Loss
estimate the amount of blood loss when the amount of
hemorrhage is small, and they tend to underestimate the To complement what limited vital signs measurements
amount of blood loss with larger amounts of hemor- are available, providers frequently use the character and
rhage. Furthermore, the type of surface on which the intensity of pulses, in addition to visual estimation of
blood is deposited can impact the visual estimation of blood loss, to assess the amount of hemorrhage. Un-
the amount of hemorrhage. To aid providers with the fortunately, the visual estimation of blood loss in the
ability to accurately estimate blood loss, we took several field medical-care environment can be significantly inac-
units of expired packed red blood cells and deposited curate. In these circumstances, injuries with minimal
1–5
them in different ways on varying surfaces to mimic the blood loss tend to result in an overestimate of hemor-
visual impression of combat casualties. rhage, while with large volumes of blood loss, the ten-
dency is the opposite, with an underestimation of the
4,6
Keywords: hemorrhage diagnosis; war; military medicine; amount of hemorrhage. Additionally, the surface on
emergency medical services which blood is deposited can affect the perception of
the amount of blood loss, with a surface of sandy soil
causing a decrease in the appreciation for the amount
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Introduction of hemorrhage. For example, Kreutziger et al. showed
that blood deposited on hard, nonabsorbent surfaces
Providers in the military prehospital environment fre- such as concrete or polyvinyl chloride floors resulted in
quently have to make assessments about the amount of blood pools 13 times larger than that deposited on for-
blood loss sustained by a patient on the battlefield. The est soil or carpet. Consistent with these findings, it is
estimation of blood loss is important because it impacts our experience that in hot, dry climates, such as Sahara
multiple decisions such as the required speed of evacua- Desert regions of Africa, there is significant absorption
tion, the need for transfusion of blood products, and the of blood by the soil, causing significant underapprecia-
use of tranexamic acid. These decisions are frequently tion of the volume of hemorrhage.
made in difficult environments with limited objective
measurement of vital signs available to assist the deci- Background
sion-making process. During a deployment, we were exposed to a clinical case
that illustrated the difficulties with visual estimation of
Because of space and weight restrictions, military pre- blood loss. A coalition soldier sustained a wound that
hospital providers typically carry only a small amount resulted in point-of-injury personnel reporting massive
of patient-monitoring equipment. A finger pulse oxim- blood loss based on visual estimation. Because of this
eter is often the only piece of equipment providers carry report of large blood loss combined with tachycardia,
to evaluate vital signs objectively, because of its small the individuals caring for the patient provided treatment
size and reliability. Additionally, in certain operational for massive hemorrhage. However, after definitive treat-
environments, such as aeromedical evacuation, vibra- ment was provided at the Role 3 facility, the patient’s
tions and noise can significantly affect the functionality providers informally critiqued the prehospital treatment

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