Page 111 - JSOM Winter 2018

FIGURE 4 Intraabdominal pressures measured in the (A) hepatic region, (B) mesenteric region, and (C) gutters during use of the Abdominal
Aortic Junctional Tourniquet (AAJT).

*Differs significantly from baseline.

FIGURE 5 Kaplan-Meier survival curves for the Abdominal Aortic potassium levels in comparison with control animals. This dif-
Junctional Tourniquet (AAJT) and control groups at 300 minutes ference in these results is likely due to the prolonged ischemia
after the intervention. time seen in the Kheirabadi et al. study (120 minutes versus
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30 minutes). This complication can likely be avoided with de-
creased application time but may not be practical in situations
where long delays in evacuation are expected (e.g., antiaccess
area denial theaters of operation).

Despite these concerning aspects noted in previous studies,
several reports of application showed an increase in MAP and
an expected decrease in femoral arterial pressures. 11,12,18 This
is consistent with both previous studies and our current study.
The most problematic aspect of application with this modifi-
cation, however, was noted on necropsy, when it was found
that a significant number of animals had a thrombus within
the IVC, which has not been demonstrated in previous studies
with the AAJT, to our knowledge. 2,17, Compared with the un-
However, despite promising preliminary results in our pilot modified AAJT, development of thrombi may be attributable
study, we were unable to demonstrate efficacy of this approach to the plate creating a discrete pressure overlying the IVC with
in a large-animal translational model of NCTH. subsequent venous pooling. We observed an increase in central
venous pressure and femoral venous pressures after applica-
Although we demonstrated a primary response of an increase tion, which may support this theory.
in MAP after application, as seen in previous studies that used
the AAJT without modifications, we did not see improvement Although the AAJT-TP in our experiments did not improve
in overall survival. 12,18 Although we noted an improvement overall survival, there have been other successes within the
in blood loss with application of the AAJT-TP in our unpub- field of NCTH control, including IABO. We have found that
lished pilot studies, we did not see a difference in the full study, IABO is an excellent temporizing measure in lieu of thoracot-
and there were multiple adverse effects that may have played a omy for aortic occlusion, as evidenced by White et al., who
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role in the rate of survival. demonstrated a decreased physiologic burden with the use of
IABO compared to resuscitative thoracotomy. However, de-
As expected, we noted elevated peak inspiratory pressures im- spite promising results in short periods of aortic occlusion,
mediately after application. Although swine were able to be IABO still creates a secondary injury, owing to its distal isch-
ventilated without consequences of poor oxygen saturation, emic burden, and lacks feasibility in austere environments. 9,20–22
this may be a concerning factor in placement on patients with- These factors limit IABO’s potential for PFC and, therefore,
out a definitive airway. Kragh et al. demonstrated the use additional avenues for NCTH management must be explored.
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of AAJT without respiratory compromise on human subjects;
however, the application was determined to be effective if Manipulation of intraabdominal pressure may remain a vi-
there was only a loss of lower extremity Doppler signals. Their able alternative to endovascular intervention in NCTH. Al-
results may be feasible for junctional hemorrhage control but though this particular approach to increasing intraabdominal
may not be effective in control of intraabdominal hemorrhage pressures to control NCTH may not have been efficacious,
without a definitive airway. there are other avenues where discrete application of intraab-
dominal pressure could successfully manage NCTH. Intraab-
Additional potential complications that have been described dominal polymer foams and intraabdominal administration
in the literature are the metabolic acidosis and hyperkalemia of XSTAT (RevMedx, https://www.revmedx.com/) have great
associated with prolonged application. Kheirabadi et al. potential in this paradigm (data not published). In cases of
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described instances similar to a crush injury, with episodes of intraabdominal hemorrhage, NCTH control may be aided by
respiratory arrest, sudden hyperkalemia, and metabolic acido- development of a product capable of deployment into the ab-
sis after immediate release of the tourniquet. Our study did domen via an external wound or abdominal access. Intraab-
12
not demonstrate these effects and there was no difference in dominal packing is currently our only option, but this requires
Abdominal Aortic Junctional Tourniquet–Torso Plate in Noncompressible Torso Hemorrhage | 109