Page 91 - Journal of Special Operations Medicine - Spring 2017

for hemorrhage. Their clinical impression was that hem- Figure 1 PRBCs (330mL) Applied Without Force to
orrhage was minimal. Although the critique did not Moderately Dry Sand/Rock Soil.
appear to be accurate given the environment and infor-
mation available at the time, it did stimulate discussion
among the study authors about the accuracy of visual
estimation of blood volume and the tendency to overes-
timate small volumes of hemorrhage.

As part of our normal duties, we regularly store, trans-
port, and destroy blood products. Unfortunately, be-
cause of logistical constraints, no fresh whole blood or
platelets were readily available to take clinical images.
Therefore, available packed red blood cells (PRBCs)
were used for illustrative purposes. During photography
of simulated blood loss, the study authors were used as
a size reference. However, there was no increased risk
of blood product exposure above and beyond the risks
encountered during the performance of our daily duties.
Figure 2 PRBCs (330mL) Applied With Force to Moderately
Clinical Images Dry Sand/Rock Soil.
Given these issues, we sought to visually illustrate dif-
ferent amounts of blood on multiple surfaces to improve
visual estimation of blood loss by medical personnel. To
do this, we took several units of expired PRBCs (250–
350mL) and placed their contents onto several differ-
ent surfaces. We applied the blood in different ways to
mimic different possible wounding patterns and took
photographs with a study author as a size reference
who is 72 inches tall and 195 lb. Figure 1 shows 1 unit
of PRBCs on a moderately dry surface of mixed sand
and stone similar to what is encountered in Afghani-
stan. Figure 2 shows the same volume of blood applied
to similar ground with greater force, resulting in more
of a splatter pattern. Figure 3 shows 1 unit of PRBCs
deposited on the same sand/rock soil while moving, to
simulate a wounded casualty who continued to move af-
ter injury, creating a blood trail. To simulate a different Figure 3 PRBCs (330mL) applied while moving to dry sand/
surface, Figure 4 shows 1 unit of PRBCs applied on a rock soil.
concrete surface. Finally, Figure 5 shows 3 units, or ap-
proximately 990mL, of blood deposited on moderately
dry sandy/rocky soil.

One unit of PRBCs contains approximately 330mL of
blood product. The average individual has approxi-
mately 70mL/kg total blood volume. For example, a
8
150-lb (70kg) Soldier would have a 4.9L blood volume
and a 200-lb (90kg) Soldier would have 6.3L of total
blood volume. The volume of 1 unit of PRBCs depicted
in Figures 1–4 would thus represent 5% to 7% of the
total blood volume, depending upon the size of the
individual.

The Committee on Tactical Combat Casualty Care
guidelines recommend treating hemorrhagic shock with
hypotensive resuscitation. Their guidelines state that re-
9
suscitation should be started with blood products when

Visual Estimation of Blood Loss 69