The central venous pressure catheter primarily helps evaluate which of the following?

• A. Right ventricular function, right atrial filling pressure, and circulating blood volume
• B. Pulmonary capillary wedge pressure
• C. Left atrial pressure
• D. Systemic vascular resistance

Answer: (B)

The key idea is differentiating what each catheter tells you about preload on the right side versus the left side of the heart. A central venous pressure line mainly reflects right atrial pressure, which mirrors right-sided preload, venous return, and circulating blood volume. It’s a tool for gauging how much filling pressure the right heart has before it contracts.

Pulmonary capillary wedge pressure, by contrast, is obtained with a catheter advanced into a branch of the pulmonary artery and then wedged with the balloon inflated. The pressure measured at this wedged position reflects the pressure in the left atrium, and therefore the left-sided preload and left ventricular filling pressures. This left-sided pressure is what wedge pressure estimates, and that’s why it’s used to assess left heart filling conditions.

So, while a central venous line informs about right-sided pressures and volume status, the wedge pressure provides insight into left atrial (and thus left-sided) filling pressures.