Which parameter has a normal range with an upper limit around 12 mmHg?

• A. CVP
• B. SpO2
• C. Cardiac Output
• D. Pulmonary Capillary Wedge Pressure

Answer: (D)

Pulmonary Capillary Wedge Pressure reflects left-sided filling pressures. It’s measured by wedging a catheter in a branch of the pulmonary artery and serves as an indirect estimate of left atrial pressure. The normal range is about 6 to 12 mmHg, so the upper limit is around 12. This makes it the parameter whose normal range sits at that higher end of a pressure scale.

Understanding the others helps: CVP also uses mmHg but normally sits roughly 2 to 6 mmHg, not near 12. Cardiac output is a flow, usually expressed in liters per minute, not a pressure. SpO2 is a percentage of oxygen saturation, not a pressure measurement. Elevated wedge pressure points to increased left-sided filling pressures (left heart failure, volume overload), while CVP reflects right-sided preload and will stay well below 12 in healthy individuals.