What does central venous pressure (CVP) measurement primarily indicate?

• A. Measures preload by pressure in the right superior vena cava
• B. Measures systemic vascular resistance
• C. Indicates left ventricular end-diastolic pressure
• D. Reflects oxygen carrying capacity

Answer: (A)

Central venous pressure primarily reflects the filling pressure of the right side of the heart. Measured in the central venous system near the right atrium, it serves as an indirect indicator of right ventricular preload—the amount of blood returning to the heart and ready to be pumped. This is why CVP is used to assess fluid status and guide fluid therapy for the right heart.

It is not a direct measure of systemic vascular resistance, which depends on arterial tone; it does not directly indicate left ventricular end-diastolic pressure (that left-sided pressure is best estimated by left atrial or pulmonary artery wedge pressures); and it has nothing to do with oxygen carrying capacity, which depends on hemoglobin and oxygen saturation.