No, a Swan-Ganz catheter does NOT measure arterial blood pressure
A Swan-Ganz (pulmonary artery) catheter measures pressures within the right heart and pulmonary circulation—specifically right atrial pressure, pulmonary artery pressure, and pulmonary artery wedge pressure—but it does not measure systemic arterial blood pressure 1.
What the Swan-Ganz Catheter Actually Measures
The pulmonary artery catheter is inserted through central venous access into the right side of the heart and floated into the pulmonary artery 2. Its ports allow measurement of:
- Right atrial (RA) pressure via the proximal port
- Pulmonary artery (PA) pressure via the distal port
- Pulmonary artery wedge/occlusion pressure (PAWP) when the balloon is inflated
- Cardiac output via thermodilution
- Mixed venous oxygen saturation from PA blood sampling 1
These measurements provide hemodynamic assessment of right heart function and left ventricular filling pressures (indirectly via PAWP), but they do not capture systemic arterial pressure.
Why This Distinction Matters Clinically
If you need to monitor arterial blood pressure in a critically ill patient—which you almost certainly do if you're placing a Swan-Ganz catheter—you must use a separate arterial catheter (typically radial or femoral) 3. The 2025 ESICM guidelines are explicit: arterial pressure should be monitored with an arterial catheter in shock that is not responsive to initial therapy and/or requiring vasopressor infusion 3.
Common Pitfall to Avoid
Do not assume that having a PA catheter in place provides all the hemodynamic monitoring you need. In patients sick enough to warrant PA catheterization (e.g., severe pulmonary hypertension, cardiogenic shock, complex hemodynamic assessment), you will nearly always need both:
- An arterial line for continuous systemic blood pressure monitoring
- A Swan-Ganz catheter for right heart and pulmonary hemodynamics
The PA catheter tells you about cardiac output, filling pressures, and pulmonary vascular resistance; the arterial line tells you about systemic perfusion pressure and allows repeated arterial blood gas sampling 3.