Figure 32-37 Overwedging of the pulmonary artery (PA) catheter causes artifactual waveform recordings. The first two attempts to inflate the PA catheter balloon (first two arrows) produce a nonpulsatile, increasing pressure caused by an occluded catheter tip. After the catheter is withdrawn slightly, balloon inflation allows proper wedge pressure measurement (third arrow). Before the third attempt at balloon inflation, the PA pressure lumen is flushed. Flushing restores the appropriate pulsatile pressure detailed to the PA and wedge pressure waveforms on the right side of the trace. (Redrawn from Mark JB: Atlas of Cardiovascular Monitoring. New York, Churchill Livingstone, 1998, Fig. 5-7.)