Page 38 - Journal of Special Operations Medicine - Spring 2016

Note that (1) it is anticipated that if XStat is being pur- clavicle; 61% of patients with penetrating trauma to the
chased in large quantity by the DoD, production costs subclavian vessels died before arriving at a hospital in
and price to the government will drop in the future; one large case series. Interestingly, isolated injuries to
28
the proposed target price for a single XStat applicator the subclavian vein have been reported to be associated
is $130 ; and (2) more than one applicator of XStat with a higher mortality rate than isolated injuries to the
22
may be required to fill a wound cavity and achieve the subclavian artery. 28,29 Two possible reasons proposed for
internal increase in pressure in the wound cavity needed this observation have been offered: the first is that the
to achieve hemostasis. Up to eight applicators of XStat vein is not able to contract as effectively as the artery af-
were allowed in the Cestero et al. and Mueller et al. ter an injury; the second is that subclavian vein injuries
studies. 7,26 The median number of XStat applicators may result in the introduction of air into the venous sys-
used in the Cestero et al. study was six. 7 tem and produce death by impeding pulmonary artery
blood flow or causing cardiac or cerebral ischemia in in-
dividuals with a patent foramen ovale or other right-to-
Discussion left shunts in the heart or lungs. Bleeding that occurs
28
from wounds in this area, as well as other wounds from
The Need for XStat deep, narrow wound tracts, may be difficult to control if
For deep-tract or narrow-entrance wounds, visualiza- the bleeding is at a location not amenable to junctional
tion of the source of bleeding is difficult and packing or extremity tourniquet use.
the wound can be time consuming and possibly painful
for the casualty. In addition, using one of the CoTCCC- The initial study by Mueller et al. of a chitosan-coated,
26
recommended hemostatic dressings requires that manual compressed-sponge-based hemostatic system used a
compression be maintained on the wound for 3 minutes. swine model of subclavian artery and vein bleeding cre-
This period of manual compression is not required with ated through a 4.5cm wound. This model was chosen
XStat. because the bleeding subclavian vessels are difficult to
compress, in contrast to the flatter geometry of wounds
XStat Efficacy Studies in the inguinal junctional area that allows for more effec-
The current recommendation for controlling junctional tive pressure when applying Combat Gauze. There were
hemorrhage in TCCC is the immediate application of eight animals in the minisponge study group and eight
Combat Gauze and manual pressure followed by the use in a control Combat Gauze group. There was no exter-
of one of the three junctional tourniquets as soon as one nal compression used in the minisponge group and up
is available. 3,27 to eight applicators of the minisponges per animal were
used to fill the wound cavity. The minisponges were ap-
XStat was specifically designed for the battlefield treat- plied within the 4-minute application time window. One
ment of junctional bleeding from narrow-tract wounds. Combat Gauze and one Kerlix gauze (MedTronic; http://
XStat is a hemostatic adjunct that applies internal pres- www.medtronic.com) were used to pack the wound in
sure to bleeding sites in the depths of cavitary wounds, the control group. These dressings were applied with 3
as opposed to hemostatic dressings, which are designed minutes of direct pressure, per the manufacturer’s direc-
and labeled for external use and require manual pres- tions. At 60 minutes, survival was 100% (eight of eight)
sure after application. This may be especially important in the minisponge group and 37.5% (three of eight) in
when dealing with small wounds that do not allow for the Combat Gauze group. 26
direct visualization of the bleeding vessel. The XStat sys-
tem enables the required quantity of compressed sponges Cestero et al. compared XStat with Combat Gauze
7
to be placed quickly into a narrow-tract wound. The (with and without compression) in a porcine model of
subsequent expansion of the compressed minisponges subclavian artery and vein transection similar to that
provides internal pressure in the wound cavity and fa- used in the Mueller et al. study. (Note on the terminol-
26
cilitates hemostatic interaction (adherence) of the chi- ogy: the wound that both groups of investigators created
tosan coating with the bleeding tissues with little or no in their pigs was an axillary wound and the vessels that
external pressure needed. were transected were, in actuality, the axillary artery and
vein. To access the subclavian artery in pigs, the surgeon
One point to note about the bleeding model used in must penetrate the pleural space, which was not done
the two studies discussed in the following paragraphs in either study. The only vessels that can be accessed at
is that injuries to the subclavian vessels are associated the upper-extremity junctional region in porcine models
with a high mortality rate, because of the large diam- are axillary vessels. The terminology used in these stud-
eter of these vessels, the resultant high bleeding rate that ies is used in this article, with this caveat.) Access to
injuries to them produce, and the difficulty in applying the left subclavian artery and vein was made through a
pressure to the bleeding site because of the overlying 4.5cm skin incision, approximately 4cm parallel to the

22 Journal of Special Operations Medicine Volume 16, Edition 1/Spring 2016