The proximal lumen port on a Swan-Ganz catheter has which of the following characteristics?

The proximal lumen port on a Swan-Ganz catheter has which of the following characteristics?

• A. Location approximately 30 cm back from distal tip inside the right atrium or superior vena cava; measures CVP/RA pressure, and used as the injectate port for thermodilution.
• B. Location at the distal tip of the catheter in the pulmonary artery; measures PCWP.
• C. Location in the left ventricle; measures LVEDP.
• D. Location in the femoral vein; measures venous return.

Answer: (A)

The proximal lumen port is intentionally placed in the right atrium or superior vena cava, which lets it directly sense central venous pressure (CVP), i.e., right atrial pressure. It is also the injectate port used for thermodilution, where a small amount of cold saline is injected and the resulting temperature change is measured downstream to calculate cardiac output. This combination—CVP measurement and thermodilution injectate port—fits exactly with how the proximal port is designed to function when the distal tip sits in the pulmonary artery. The distal tip is what measures pressures and pressures when wedged in the pulmonary artery (and ultimately relates to left atrial pressure), not the proximal port. The choice referencing a location in the femoral vein or measuring LVEDP does not match how the Swan-Ganz catheter is structured and used.

The proximal lumen port is intentionally placed in the right atrium or superior vena cava, which lets it directly sense central venous pressure (CVP), i.e., right atrial pressure. It is also the injectate port used for thermodilution, where a small amount of cold saline is injected and the resulting temperature change is measured downstream to calculate cardiac output. This combination—CVP measurement and thermodilution injectate port—fits exactly with how the proximal port is designed to function when the distal tip sits in the pulmonary artery. The distal tip is what measures pressures and pressures when wedged in the pulmonary artery (and ultimately relates to left atrial pressure), not the proximal port. The choice referencing a location in the femoral vein or measuring LVEDP does not match how the Swan-Ganz catheter is structured and used.