RT Journal Article SR Electronic T1 5 Abdominal aortic junctional tourniquets – clinically important increases in pressure in aortic zone 1 and zone 3 in a cadaveric study directly relevent to combat medics treating non-compressible torso haemorrhage JF BMJ Military Health JO BMJ Mil Health FD British Medical Journal Publishing Group SP e3 DO 10.1136/bmjmilitary-2025-colt.5 VO 171 IS 3 A1 Smith, Thomas A1 Pallister, Ian A1 Parker, Paul YR 2025 UL http://militaryhealth.bmj.com/content/171/3/e3.5.abstract AB Background ‘Non-compressible’ torso haemorrhage (NCTH) is the leading cause of preventable battlefield death. UK Joint Theatre Trauma Registry (JTTR) analysis 2002–12 showed 85.5% NCTH mortality. Gas insufflation and hyper-pressure intra-peritoneal fluid animal studies demonstrated significant reductions in blood loss in splanchnic injuries. We hypothesised that the non-invasive Abdominal Aortic Junctional Tourniquet-Stabilised (AAJT-S) would be a forward medic intervention to tamponade bleeding from coeliac trunk vessels in zone 1 by generating clinically significant proximal epigastric compartment pressure.Methods Four cadaveric donors each had two balloon manometers placed intra-peritoneally: one epigastric and one retropubic. Baseline pressures of 8 cmH2O were set (equating mean intra-abdominal pressure (IAP.)) AAJT-S was applied. Pressures were contemporaneously recorded. AAJT-S was removed, and 500 ml of water was added through the epigastric aperture to simulate blood. The manometer was replaced and reset to 8 cmH2O. AAJT-S was re-applied, IAP steady pressures were again recorded.Results Proximal compartment pressures reached a mean of 54.6 cmH2O (40.2 mmHg); distal compartment pressures a mean of 46 cmH2O (34 mmHg.) With 500 ml intraperitoneal fluid, proximal compartment achieved a mean of 52.25 cmH2O (38.4 mmHg); distal compartment achieved a mean of 35 cmH2O (25.7 mmHg.) BMI had a statistically significant inverse effect, in our range (16.7–22.9.) This proved clinically insignificant, with sufficient pressure still achieved in all tests.Conclusion AAJT-S at 250 mmHg achieves proximal epigastric compartment pressures of 40mmHg, with or without 500 ml simulated free blood in the abdomen. This represents a highly significant and titratable reduction in blood flow in coeliac trunk branches. BMI does not have a clinically significant effect. AAJT-S application also produces Zone 3 aortic and inferior vena cava occlusion. AAJT-S may be a point of injury intervention for forward medics that contributes to non-surgical haemorrhage control and likely clot stabilisation for Zone 1 vascular and solid organ injuries.