Bi-manual proximal external aortic compression after major abdominal-pelvic trauma and during ambulance transfer: A simulation study

Background: Applying manual pressure after hemorrhage is intuitive, cost-free, and logistically-simple. When direct abdominal-pelvic compression fails, clinicians can attempt indirect proximal-external-aortic-compression (PEAC), while expediting transfer and definitive rescue. This study quantifies the sustainability of simulated bi-manual PEAC both immediately on scene and during subsequent ambulance transfer. The goal is to understand when bi-manual PEAC might be clinically-useful, and when to prioritize compression-devices or endovascular-occlusion.

Methods: We developed a simulated central vessel compression model utilizing a digital scale and Malbrain intra-abdominal pressure monitor inside a cardiopulmonary resuscitation mannequin. Twenty prehospital health care professionals (HCPs) performed simulated bimanual PEAC i) while stationary and ii) inside an 80km/h ambulance on a closed driving-track. Participants compressed at "the maximal effort they could maintain for 20min". Results were measured in mmHg applied-pressure and kilograms compressive-weight. The Borg scale of perceived-exertion was used to assess sustainability, with <16 regarded as acceptable.

Results: While stationary all participants could maintain 20min of compressive pressure/weight: within five-percent of their starting effort, and with a Borg-score <16. Participants applied 88-300mmHg compression pressure; (mean 180mmHg), 14-55kg compression-weight (mean 33kg), and 37-66% of their bodyweight (mean 43%). In contrast, participants could not apply consistent or sustained compression in a moving ambulance: Borg Score exceeded 16 in all cases.

Conclusions: Survival following major abdominal-pelvic hemorrhage requires expedited operative/interventional rescue. Firstly, however, we must temporize pre-hospital exsanguination both on scene and during transfer. Despite limitations, our work suggests PEAC is feasible while waiting for, but not during, ambulance-transfer. Accordingly, we propose a chain-of-survival that cautions against over-reliance on manual PEAC, while supporting pre-hospital devices, endovascular occlusion, and expeditious but safe hospital-transfer.