Additional Features of Pulmonary Artery Catheters
The popularity of PAC monitoring relates in large part to the
fact that these catheters are multipurpose and provide
a wide range of supplementary features for therapeutic and diagnostic applications.
In addition to the standard lumens that allow measurement of PAP and CVP, catheters
may have an additional venous infusion lumen opening either 20 or 30 cm from the
catheter tip. Special PACs are available that allow temporary endocardial pacing
or intracardiac ECG recording. One such catheter has five small electrodes embedded
in its outer wall, two located approximately 20 cm from the catheter tip and three
located approximately 30 cm from the catheter tip. Combinations of these electrodes
allow bipolar endocardial ventricular, atrial, or atrioventricular pacing.[597]
Other pacing PACs do not have the pacing electrodes permanently attached but instead
have a special lumen that opens in the right ventricle, through which a thin bipolar
wire may be introduced for endocardial ventricular pacing.[598]
Another type of pacing PAC has special atrial and ventricular lumens that accommodate
two separate wires to allow atrioventricular sequential pacing.[599]
Although successful endocardial pacing is achieved in most patients with these catheters,
reliable catheter positioning is more problematic than with standard PACs. Patient
movement or PAC balloon inflation to measure wedge pressure may alter the position
of the catheter or dislodge the wires within the heart and thereby interrupt pacing.
