A critical patient with multiple traumas has a Swan-Ganz catheter in place for invasive hemodynamic monitoring. Which of these values requires the brief inflation of a balloon at the distal port of the catheter?

A Swan-Ganz catheter is one example of an invasive hemodynamic monitoring system. It has several ports/lumens that allow for specific information/measurements to be taken depending on their location. The distal end of the catheter or the pulmonary artery port will measure the pulmonary artery pressure; however, it also contains a balloon that when inflated measures the pulmonary capillary wedge pressure. Central venous pressure is measured at the proximal port of the catheter, and cardiac output (as measured by a Swan-Ganz) can be determined using a thermistor, which is also located at the distal end of the catheter.