How is pulmonary artery catheterization (PAC) performed?

Updated: Dec 22, 2017
  • Author: Bojan Paunovic, MD; Chief Editor: Karlheinz Peter, MD, PhD  more...
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Answer

The PAC is inserted percutaneously into a major vein (jugular, subclavian, femoral) via an introducer sheath. The actual venous access techniques are not described here, but the following points are important. Preference considerations for cannulation of the great veins are as follows:

  • Right internal jugular vein (RIJ) - Shortest and straightest path to the heart

  • Left subclavian - Does not require the PAC to pass and course at an acute angle to enter the SVC (compared to the right subclavian or left internal jugular [LIJ])

  • Femoral veins - These access points are distant sites, from which passing a PAC into the heart can be difficult, especially if the right-sided cardiac chambers are enlarged. Often, fluoroscopic assistance is necessary. Nevertheless, these sites are compressible and may be preferable if the risk of hemorrhage is high.

As with any catheterization procedure, sterile technique is essential. The total length of a PAC is approximately 150 cm; extra sterile towels around the head, shoulders, and chest ensure that aseptic technique is not compromised.

While the Trendelenburg position is used for venous access (internal jugular [IJ] and subclavian routes), passage of the PAC is easier when the patient subsequently is placed flat or slightly upright.

Before insertion, check the PAC for cracks and kinks. Then, check balloon function (see image below), connect all lumens to stopcocks, and flush them to eliminate air bubbles. Flick the PAC tip to check frequency response. Finally, the PAC is threaded through a sterile sleeve (be sure to check orientation) to ensure sterility of the PAC after insertion and allow some adjustment of position.

The balloon of the catheter should be checked prio The balloon of the catheter should be checked prior to insertion.

The packaging of the PAC causes it to have a preformed curve. This can be used to facilitate passage into the PA. The direction in which the curl is inserted into the introducer depends on which vein is cannulated. For instance, from the head of the bed using the RIJ approach, the curl should be in the direction of the patient's left shoulder (concave-cephalad). Once the PAC is in the RV, a clockwise quarter turn moves the tip anteriorly to allow easier passage into the PA.

After inserting the PAC as far as the 20-cm mark (30-cm mark if the femoral route used), the balloon is inflated with air. Inflation should be slow and controlled (1 mL/s) and should not surpass the recommended volume (usually 1.5 mL). Always inflate the balloon before advancing the PAC, and always deflate the balloon before withdrawing the PAC.

Always use continuous pressure monitoring from the distal lumen. Watch the monitor for changes in the waveform and abnormal cardiac rhythms. From the RIJ approach, the RA is entered at approximately 25 cm, the RV at approximately 30 cm, and the PA at approximately 40 cm; the PCWP can be identified at approximately 45 cm.

If an RV waveform still present approximately 20 cm after the initial RV pattern appears, the catheter may be coiling in the RV. If withdrawal is necessary, always proceed slowly to decrease the risk of knotting the catheter upon itself. If the catheter is knotted, fluoroscopy may be necessary to visualize the catheter and remove the knot. As a last resort, slowly withdraw the PAC to the point where it catches on the introducer tip. From this point, the PAC and introducer can be removed as one unit. Apply prompt pressure for a minimum of 5 minutes. If bleeding persists, suturing the site may be necessary.

Once the PCWP is obtained and the catheter sleeve secured, make sure the PCWP pattern is reproducible before removing the sterile field. Also, determine the volume of air in the balloon required to obtain a PCWP waveform. Volumes less than half the balloon maximum may indicate that the tip is too far distal. Some clinicians advocate that, after establishing that the PA diastolic pressure is equal to the PCWP pressure, further balloon inflations are unnecessary and the PA diastolic pressure should be used as the parameter to assess left ventricular (LV) filling; this relationship may not hold if the clinical situation changes.

Once the procedure is complete, obtain a chest radiograph to check the position of the PAC and to assess for central venous access complications (eg, pneumothorax).

An interesting real-time online video is available to enhance the visualization of the course of the catheter as it passes through the heart. [34, 35, 36]


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