Which port on a Swan-Ganz catheter is the balloon port?

• A. Balloon port
• B. Distal Lumen Port
• C. Thermistor Lumen Port
• D. Injectate Lumen Port

Answer: (A)

The balloon port is the channel used to inflate the balloon at the tip of a Swan-Ganz catheter. Inflating this balloon briefly occludes a small branch of the pulmonary artery, allowing the catheter tip to wedge and the pressure reading to reflect the left atrial pressure (the wedge pressure). This inflation function is what defines the balloon port. The other ports serve different roles: the distal lumen port measures pressure in the pulmonary artery when not wedged; the thermistor lumen contains the temperature sensor used for thermodilution to calculate cardiac output; and the injectate lumen is used to inject saline for the thermodilution measurement. So the port that inflates the balloon is the balloon port.