What hemodynamic pattern characterizes cardiogenic shock?

What hemodynamic pattern characterizes cardiogenic shock?

• A. High mixed venous oxygen saturation.
• B. Low cardiac output with elevated filling pressures and sustained hypotension; low mixed venous oxygen saturation.
• C. Normal cardiac output with normal filling pressures.
• D. Low cardiac output with low filling pressures.

Answer: (B)

In cardiogenic shock the heart’s pumping ability is severely impaired, so cardiac output falls. Because the ventricle can’t eject effectively, filling pressures rise due to backup and venous congestion. With reduced forward flow, tissues receive less oxygen, prompting the body to extract more for metabolism, which lowers the mixed venous oxygen saturation. The combination—low cardiac output, elevated filling pressures, sustained low blood pressure, and low mixed venous O2 saturation—fits the hemodynamic pattern of cardiogenic shock. Why the other patterns don’t fit: a high mixed venous saturation would suggest inadequate tissue extraction (as seen in some septic states), not cardiogenic shock. Normal cardiac output with normal filling pressures isn’t shock. Low cardiac output with low filling pressures points toward hypovolemic states rather than pump failure.

In cardiogenic shock the heart’s pumping ability is severely impaired, so cardiac output falls. Because the ventricle can’t eject effectively, filling pressures rise due to backup and venous congestion. With reduced forward flow, tissues receive less oxygen, prompting the body to extract more for metabolism, which lowers the mixed venous oxygen saturation. The combination—low cardiac output, elevated filling pressures, sustained low blood pressure, and low mixed venous O2 saturation—fits the hemodynamic pattern of cardiogenic shock.

Why the other patterns don’t fit: a high mixed venous saturation would suggest inadequate tissue extraction (as seen in some septic states), not cardiogenic shock. Normal cardiac output with normal filling pressures isn’t shock. Low cardiac output with low filling pressures points toward hypovolemic states rather than pump failure.