What does the proximal port of the catheter measure in hemodynamics?

The proximal port of a catheter, particularly in the context of a pulmonary artery catheter, measures central venous pressure (CVP). This measurement reflects the pressure in the right atrium or superior vena cava and is indicative of the volume status and function of the right side of the heart. CVP can help clinicians assess the patient's fluid status and guide management of fluid administration, especially in critically ill patients.

In contrast, the other measurements like pulmonary artery pressure (PAP) and pulmonary capillary wedge pressure (PCWP) are obtained from different ports of the catheter. The distal port usually measures PAP and can be wedged to measure PCWP, which reflects left atrial pressure. Cardiac output (QT) is assessed through additional methodologies and is not specifically measured by the proximal port. Understanding these functions helps in interpreting hemodynamic data accurately, ensuring appropriate patient care.