What causes damage to microcirculation in traumatic asphyxia?

The correct choice related to the cause of damage to microcirculation in traumatic asphyxia is the backflow of blood into the superior vena cava. Traumatic asphyxia typically occurs when there is a significant compressive force applied to the thoracic region, often due to a heavy object falling on a person or when someone is involved in a traumatic event, such as a car accident. This pressure can obstruct the venous return, particularly affecting the superior vena cava, which is responsible for draining blood from the upper body back to the heart.

When the superior vena cava is compressed, there is a disruption in the normal flow of blood, leading to increased venous pressure in the upper body. This pressure can cause a cascade of vascular changes, resulting in the failure of microcirculation. As the blood flow stagnates, red blood cells can rupture, leading to petechiae (small hemorrhages) in the conjunctiva and other areas, and contributing to the characteristic cyanotic appearance seen in traumatic asphyxia.

While loss of blood volume, shock due to external bleeding, and injury to lung parenchyma can certainly contribute to overall hemodynamic instability and respiratory distress, they are not the direct mechanisms causing microcirculatory damage