Blunt trauma to large vessels: a mathematical study

Abstract

Background: Blunt trauma causes short-term compression of some or all parts of the chest, abdomen or pelvis and changes hemodynamics of the blood. Short-term compression caused by trauma also results in a short-term decrease in the diameter of blood vessels. It has been shown that with a sudden change in the diameter of a tube or in the direction of the flow, the slowermoving fluid near the wall stops or reverses direction, which is known as boundary layer separation (BLS). We hypothesized that a sudden change in the diameter of elastic vessel that results from compression may lead not only to BLS but also to other hemodynamic changes that can damage endothelium.

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“…According to the above and to our previous research [ 21 , 27 ], three internal factors have been identified (the Dean number, compression and blood flow velocity) that can play a dominant role with respect to endothelium damages and resulting vessel rupture. Let me now investigate the conditions that appear as the result of fluid (plasma) and particle (erythrocyte) movement, i.e.…”

“…Also, according to tables 1 , 2 , 3 , the curvature may play a significant role when the vessel is compressed as the result, for example, of injury. The compressed part of the vessel can increase the shear stress [ 27 ]; however, when the curvature is significant, the shear stress may become even greater owing to the influence of both curvature and compression. Thus, the Dean number is an important factor to consider when determining the shear stress acting on the external wall of the vessel.…”

“…In addition, according to tables 1 , 2 , 3 , the shear stress may exceed the physiological threshold calculated for the endothelium (i.e. 40 N/m 2 ) at the extreme value of blood velocity (1.2 m/s) [ 27 , 29 ].…”

“…Let me now determine the association between yield velocity and shear stress [ 27 , 29 ]. Calculations are given in Tables 4 , 5 and 6 .…”

“…As we showed previously, blunt trauma may lead to certain hemodynamic peculiarities that can cause damage to the endothelium and rupture of the vessel [ 21 , 27 ]. The aim of this research was to investigate further the complex mechanism of blunt injury to the vascular wall, with particular focus on branching parts of the vessels.…”