Influence of catheter tip position on pulmonary wedge pressures.

• Simultaneously recorded left atrial and pulmonary artery wedge pressures demonstrate that the left atrial pressure pulse can be transmitted across the pulmonary capillary bed and recorded by the wedged catheter." However, such satisfactory wedge tracings are not always obtainable, and in many trials the tracing is featureless, damped or distorted by artifacts and obviously is not a true reflection of atrial pressure events." In a review of the factors which influence transmission of left atrial pressure to the wedged catheter, Wiggers suggested that the manner of lodgment of the catheter tip may be a determinant of the type of pressure waves recorded. This lodgment is clearly delineated by the wedge pulmonary arteriogram. Study of these arteriograms has revealed five different positions of the catheter tip when the usual clinical criteria for the wedge position are satisfied. The purpose of this report is to demonstrate the importance of the catheter tip position in the satisfactory recording of the left atrial pulse curve by that catheter.