Page 19 - JSOM Winter 2024

Abdominal Aortic Junctional Tourniquets –
Clinically Important Increases in Pressure in Aortic Zone 1 and Zone 3
in a Cadaveric Study Directly Relevant to Combat Medics
Treating Non-Compressible Torso Hemorrhage

Thomas Smith, MBCHB *; Ian Pallister, MD, FRCS(Tr & Orth) ;
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Paul Parker, FIMC FRCSEd(Orth) 3

ABSTRACT
Background: “Non-compressible” torso hemorrhage (NCTH) Keywords: AAJT-S; non-compressible torso hemorrhage;
is the leading cause of preventable battlefield death, requir- zone 1; zone 3; minimally-invasive; celiac trunk hemorrhage
ing rapid surgical or radiological intervention, which is essen-
tially precluded close to the point of injury. UK Joint Theatre
Trauma Registry (JTTR) analysis 2002–2012 showed 85.5% Introduction
NCTH mortality. JTTR vascular injury data 2003–2008 re-
vealed 100% mortality in named truncal vessel injuries. Gas Military medical services must be continuously striving to
insufflation and hyper-pressure intraperitoneal fluid animal improve casualty survival. “Non-compressible” torso hemor-
studies have demonstrated significant reductions in blood rhage (NCTH) is now the leading cause of preventable bat-
loss in splanchnic injuries. We hypothesized that the non- tlefield death. NCTH has been defined as hemodynamic
1–4
invasive Abdominal Aortic Junctional Tourniquet – Stabilized instability due to vascular disruption in high-grade injury
( AAJT-S) would be a forward combat medic–delivered inter- present in at least one of the pulmonary systems, solid organs,
vention to tamponade bleeding from vessels of the celiac trunk major vessels, or pelvis. 5
in descending aorta zone 1 by generating clinically significant
proximal epigastric compartment pressure. Methods: Four ca- NCTH mandates emergency surgical (or radiological) interven-
daveric donors each had two manometric water-filled balloons tion. We believe treatment of such injuries in the prehospital
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placed intra-peritoneally (1 epigastric, 1 retropubic), con- environment represents the ultimate medical challenge of this
nected to manometer tubing. Baseline pressures of 8cmH O decade. NCTH injuries are not amenable to conventional tourni-
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were set (equating mean intra-abdominal pressure (IAP). quet application. A previous UK Joint Theatre Trauma Registry
AAJT-S was applied and inflated to 250mmHg. Pressures (JTTR) analysis of 296 cases of NCTH between 2002 and 2012
were contemporaneously recorded. AAJT-S was removed, found an 85.5% mortality rate, with 75% of deaths occurring
along with the epigastric manometer. We added 500mL of before arrival to hospital. JTTR analysis of vascular injuries be-
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water to simulate blood through the epigastric aperture. The tween 2003 and 2008 had shown that 100% of casualties with
manometer was replaced and reset to 8cmH O. AAJT-S was injury to named vessels of the abdomen and torso died. Only 1
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reapplied to 250mmHg, and IAP steady pressures were again out of 25 of these patients survived to surgery. Care on the future
recorded. Results: Proximal compartment pressures reached a (far) forward battlefield will be less able to involve physician-led
mean of 54.6cmH O (40.2mmHg); distal compartment pres- care—especially in warfare at scale. There has been, thus far, no
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sures achieved a mean of 46cmH O (34mmHg.) With 500mL device readily available for combat medics such as UK Com-
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intra peritoneal fluid, proximal compartment achieved a mean bat Medical Technicians, 68Ws, 18Ds, or emergency medical
of 52.25cmH O (38.4mmHg); distal compartment achieved technicians (EMTs) to use for NCTH that minimizes further
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a mean of 35cmH O (25.7mmHg.) BMI had a statistically harm. Treatment options for these injuries by combat medics are
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significant inverse effect on epigastric pressure, in this study currently limited to direct/indirect pressure—which is often un-
range (BMIs, 16.7–22.9kg/m ). This proved clinically insignifi- sustainable, incorrect, or unachievable —and novel hemostatic
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cant, with sufficient pressure still achieved in all tests. Conclu- agents. We believe that the AAJT-S may now demonstrate a tem-
sion: The AAJT-S at 250mmHg achieves proximal epigastric porary method to successfully treat those torso hemorrhage ca-
compartment pressures of 40mmHg, with or without 500mL sualties previously considered “non-compressible.”
simulated free blood in the abdomen. This represents a highly
significant and titratable reduction in blood flow within the In live tissue models, intra-abdominal insufflation with gas,
celiac trunk branches. BMI does not have a clinically signif- self-expanding polyurethane foam, and hyper-pressure in-
icant effect. AAJT-S application also produces zone 3 aortic tra-abdominal fluid using sharp trocars have all been shown
and inferior vena cava occlusion. AAJT-S may be a point-of- to improve survival by significantly reducing blood loss in
injury intervention for forward medics that contributes to splenic, portal, hepatic, and mesenteric injuries, as well as
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non-surgical hemorrhage control and likely clot stabilization in iliac and pelvic injuries. They have been able to achieve
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for zone 1 vascular and solid organ injuries. intra-abdominal pressures of up to 40mmHg, thereby reducing
*Correspondence to Thomas Smith, Stafford Garrison Medical Centre, Staffordshire, United Kingdom ST18 0AQ or thomas.smith188@mod.
gov.uk
1 Capt. Thomas Smith is General Duties Medical Officer, 3 Medical Regiment, British Army. Prof. Ian Pallister is Consultant Trauma and Ortho-
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paedic Surgeon, Morriston Hospital, Swansea, UK. Col. Paul Parker is Consultant Trauma and Orthopaedic Surgeon, Royal Centre for Defence
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Medicine, Birmingham, UK.
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