In which type of shock would you expect an elevated mixed venous oxyhemoglobin saturation?

In distributive shock, particularly in cases like septic shock, there is a significant change in the distribution of blood flow and a reduction in systemic vascular resistance leading to widespread vasodilation. This state often causes inadequate perfusion of tissues despite normal or even increased cardiac output.

As a result, the tissues cannot utilize oxygen effectively, leading to a buildup of deoxygenated blood returning to the heart. Consequently, when measuring mixed venous oxyhemoglobin saturation (SvO2), which reflects the balance between oxygen delivery and oxygen consumption, levels can be elevated. This occurs because even though there is poor tissue oxygenation due to the inadequate perfusion, the mixed venous blood may show higher saturation levels due to the body compensating by increasing oxygen extraction from the blood; however, this exchange often does not happen effectively in distributive shock.

In contrast, other forms of shock, such as hypovolemic, cardiogenic, and obstructive shock, typically show lower mixed venous saturation due to decreased blood volume, impaired cardiac function, or obstructed flow, respectively, all of which impair oxygen delivery and hence lead to lower levels of SvO2. In hypovolemic shock, for instance, blood loss leads to reduced overall oxygen delivery