An in vitro Experimental Model for Investigating Aortic Pressure Dynamics Under Blunt Thoracic Impacts

Blunt traumatic aortic rupture (BTAR) is a life-threatening injury that can occur in high-impact events such as motor vehicle collisions, falls, and sports-related trauma involving the thorax. Despite improvements in vehicle safety features and regulations by using anthropometric test devices, BTAR remains associated with substantial clinical severity and high mortality, and its underlying rupture mechanisms are still poorly understood. We developed a novel proof of concept for a human-thorax surrogate for in vitro crash testing comprising a pulsatile heart pump, anatomically shaped silicone aorta, 3D-printed rib cage, and ballistic gel damping layer to investigate the fluid mechanics response to thoracic impact. The cardiovascular mock circulatory loop system of this surrogate was validated by obtaining physiological pressure waveforms with 120/80 mmHg of pressure and an average flowrate of 5.18 L/min. Subsequently, impacts were delivered to the sternum using a standardized pendulum system commonly employed in crash test dummy calibration. Impact severity was modulated by varying the pendulum's release height, corresponding to different kinetic energy levels. Instantaneous aortic pressure waveforms were recorded before, during, and after impact. The results demonstrate that thoracic impacts induce sharp, transient alterations in aortic pressure magnitude, with greater severity observed at higher energy levels, reaching a peak of aortic pressure of 287.01 mmHg. This experimental approach provides reproducible and physiologically relevant conditions for studying BTAR and offers valuable insights into the mechanisms underlying aortic rupture, which may guide the design of improved prevention and protection strategies.