Discrepant Bleeding Patterns in a Case of Simultaneous Injuries: Hemodynamic Consequences of Bilateral Carotid Artery Transection.

In forensic practice, differences in hemorrhage volume among multiple injuries are often used to estimate the timing of trauma. We report a rare case in which multiple injuries sustained simultaneously exhibited marked discrepancies in hemorrhagic presentation. A man in his 30s was found deceased at the scene of a single-vehicle accident, in which his car had collided with a barrier. Forensic autopsy revealed complete bilateral transection of the common carotid arteries, cervical spinal cord transection, and cervical spine fractures. Additional injuries included a liver laceration and a lower leg contusion, both of which showed minimal associated hemorrhage. The bilateral carotid artery injury was determined to be the immediate cause of death. Based on hemodynamic principles, including Hagen-Poiseuille's law, we hypothesize that the abrupt reduction in vascular resistance at the transected carotid stumps formed a low-resistance, short-circuit pathway, diverting the majority of cardiac output toward the open carotid arteries. This resulted in rapid exsanguination and minimal bleeding at other injury sites. This case underscores the importance of accounting for hemodynamic factors when evaluating wound vitality, as exclusive reliance on hemorrhage volume may lead to misinterpretation of injury timing or cause of death, particularly in complex trauma cases.