MCQ – 100477

A pulmonary artery (Swan-Ganz) catheter measures all of the following except:

Correct Answer � D Explanation

Swan-Ganz (Pulmonary Artery) Catheter:

• A balloon-tipped, flow-directed catheter used in hemodynamic monitoring, typically in critically ill patients.

• Inserted via central venous access (e.g., subclavian or internal jugular vein) → advanced through right heart → wedges in the pulmonary artery.

Parameters Measured Directly:

1. Pulmonary Artery Pressure (PAP)

2. Pulmonary Artery Wedge Pressure (PAWP)

   • Reflects left atrial pressure, and indirectly left ventricular end-diastolic pressure (LVEDP)

3. Cardiac Output (CO)

   • Measured by thermodilution technique

4. Mixed Venous Oxygen Saturation (SvO₂)

   • Reflects balance between oxygen delivery and consumption

What It Does Not Measure:

• Left Ventricular End Diastolic Volume (LVEDV)

  • This is a volume parameter, not directly measurable by a Swan-Ganz catheter.

  • It is estimated indirectly via pressure (e.g., PAWP or LVEDP) but requires echocardiography or imaging modalities for true volumetric assessment.