Page 54 - Journal of Special Operations Medicine - Fall 2015

(Figure 4A–C). Based on the interviews with SOF involving the flanks or anterior abdominal wall, severe
providers, we down-selected and prioritized a hand- blast injury with abdominal wall injuries, or high-veloc-
operated design, which resembles a caulking gun (Figure ity blunt trauma.
4D). 24
Bleeding in the abdomen may be confirmed by focused
Figure 4 A robust, fieldable delivery system was designed with assessment with sonography for trauma (FAST) or diag-
the input of Special Operations medics. (A–D) Three designs
were evaluated before developing a functional prototype. nostic peritoneal aspiration. FAST is a rapid, noninva-
sive, and sensitive test to identify fluid in the abdomen.
It is routinely performed by some (but not all) SOF
units. Evidence-based studies suggest that the technique
is easily learned, sensitive (79%–93%), highly specific
(90%–99%), and portable. 35–37 Moreover, multiple re-
ports demonstrate that military users can effectively
perform prehospital ultrasound, even in austere envi-
ronments. 38–40 In the event that FAST is not available,
users may confirm abdominal bleeding by diagnostic
peritoneal aspiration (DPA) or direct visualization upon
abdominal access, which is discussed later in this article.
Adapted from diagnostic peritoneal lavage, DPA detects
hemoperitoneum through direct aspiration of fluids af-
ter placement of a dependent intra-abdominal catheter.
The sensitivity and specificity of aspiration using a de-
pendent DPA catheter have been reported at 89% and
Following initial didactic training, all SOF end-users 100%, respectively. 41
successfully deployed the device: errors occurred in less
than 2% of critical functions. Participants rated the de- After confirming severe, exsanguinating blood loss, we
vice with an average ordinal score of 4.1 ± 0.99, demon- propose that users treat all other life-threatening co-
strating that users found it “easy” to use. morbidities. This includes control of severe bleeding
from other locations (such as extremity wounds) and
alleviation of hemo/pneumothorax. Additionally, we
Discussion
expect that foam performance will be optimized in a
Preclinical data demonstrate that self-expanding foam closed abdominal compartment: substantial disruption
has the potential to safely provide percutaneous damage of the abdominal wall (such as obvious evisceration)
control, rescuing severely injured casualties from pre- will render the foam ineffective. While the abdominal
hospital exsanguination. The following discussion con- wall can be easily assessed, end users may be unable to
ceptualizes how this device can be integrated into SOF determine the presence or absence of diaphragm inju-
medical care, including appropriate patient selection, ries, particularly in the prehospital environment. Large
preparation, and foam deployment. With the feedback reviews of the National Trauma Data Bank report the
of SOF medical providers, we have developed a delivery incidence of diaphragm injuries at an infrequent rate
system for prehospital use. of 0.43%–3%, 42,43 a rate consistent with reports from
the military. To address the safety of the foam in these
44
Patient Selection and Diagnosis cases, we previously conducted a swine study of foam
We propose that the appropriate population may be deployment in the presence of a combined liver and 1cm
identified by the coexistence of physiology consistent diameter, full-thickness diaphragm injury. Small vol-
with severe hemorrhagic shock, coupled with positive umes of foam were found in the pleural space after stud-
confirmation of bleeding within the abdominal compart- ies, and we concluded that the risk for “foamothorax”
ment. Severe hemorrhagic shock is defined in Advanced was low after penetrating injury. However, conceptu-
25
Trauma Life Support courses by elevated pulse rate ally, we believe that foam treatment should be withheld
(>120 beats/minute), decreased blood pressure (as evi- in the absence of even, bilateral breath sounds.
denced by absent peripheral pulses but palpable carotid
pulse), elevated respiratory rate (>30 breaths/minute), Once the appropriate patient is selected, users must
and altered mental status. These vital signs can be eas- intubate patients, provide analgesia and amnesia, and
34
ily assessed in the prehospital environment. Additionally, access the abdominal cavity. Based upon the expected
the casualty should have a wounding mechanism con- severity of injury and massive blood loss of casualties
sistent with the possibility of intra-abdominal bleeding, in whom we propose foam therapy, we expect that de-
such as gunshot wound to the abdomen, fragmentation finitive airway control would be required even if foam

42 Journal of Special Operations Medicine Volume 15, Edition 3/Fall 2015