Which statement about central venous pressure is true?

Which statement about central venous pressure is true?

• A. CVP is typically about 2–8 mmHg; it reflects right atrial pressure and venous return.
• B. CVP is typically about 0–2 mmHg; it reflects left atrial pressure.
• C. CVP is typically about 8–12 mmHg; it reflects systemic arterial pressure.
• D. CVP is typically about -2 to 2 mmHg; it reflects venous oxygen saturation.

Answer: (A)

Central venous pressure measures the pressure inside the right atrium and reflects the preload of the right heart, i.e., how much venous return is filling the heart. The normal range is about 2–8 mmHg, which matches the typical right atrial pressure when the system is not overloaded or depleted. This is why the statement that CVP is around 2–8 mmHg and reflects right atrial pressure and venous return is the best match. CVP does not reflect left atrial pressure—the pressures in the left atrium are higher, and CVP is a marker of the right-sided filling pressure. It also does not measure systemic arterial pressure, which is the mean arterial pressure in the arteries. Nor is CVP a measure of venous oxygen saturation (that value is SvO2, not CVP).

Central venous pressure measures the pressure inside the right atrium and reflects the preload of the right heart, i.e., how much venous return is filling the heart. The normal range is about 2–8 mmHg, which matches the typical right atrial pressure when the system is not overloaded or depleted. This is why the statement that CVP is around 2–8 mmHg and reflects right atrial pressure and venous return is the best match.

CVP does not reflect left atrial pressure—the pressures in the left atrium are higher, and CVP is a marker of the right-sided filling pressure. It also does not measure systemic arterial pressure, which is the mean arterial pressure in the arteries. Nor is CVP a measure of venous oxygen saturation (that value is SvO2, not CVP).