This procedure is for use by nursing staff in CCTC who are approved to partially withdraw a pulmonary artery catheter.



1.  A persistent wedge waveform is identified on the PA tracing.
  • the pulmonary wedge pattern will have two low pressure waves per cardiac cycle ("a" and "c") if the patient is in a sinus rhythm
  • the pulmonary artery waveform will typically have evidence of a dicrotic notch (blue arrow), and produce one tall waveform following each QRS.
  • A persistent wedged pattern indicates that the catheter has migrated into the pulmonary arterial circulation to a position where the lumen of the artery is equal to the diameter of the catheter. 
  • This obstructs blood flow and may compromise blood flow to the lung tissue. 


Figure 1: Pulmonary Artery Wedge



Figure 2: Pulmonary Artery

2. Troubleshoot system to confirm pulmonary wedge versus damp or low pressure system:
  • assess circuit from top to bottom for loose connections, air or clot
  • evaluate volume of fluid in Tycos infuser and ensure pressure is adequately tightened 
  • perform a dynamic response test by opening the flush device and observing the monitor for a dampened waveform
  • check systemic BP for generalized hypotension
  • check transducer position and rezero 
2. An overdamp system will produce a low amplitude waveform as a result of pressure transmission interference.
  • air, clot or a "leak" in the pressure circuit will diminish the ability to transmit clear waveforms
  • inadequate pressure on the circuit will dampen the waveform (generally both arterial and PA tracings will dampen as they share a common infuser)
  • in a patent system, instead of a brisk "square wave" configuration, the pressure upstroke is sloped, and the recovery is delayed 
    • dampened pulmonary and arterial waveforms generally display a slow upstroke or rise (anacrotic limb)
  • If the transducer is placed above the heart, pressures will be falsely low. If the transducer is placed below the heart, pressures will be falsely high. 
3.  If the tracing is confirmed as "wedged", check to ensure that the balloon is not locked in the inflated position:
  • when the balloon lumen is locked, the red line along the lumen tubing will be disrupted (i.e. will not show a continuous line)
3. The balloon should never be left in the locked position because it is impossible to differentiate between "locked inflated" and "locked deflated".
4. Attempt to have catheter return to a PA position spontaneously:
  • have patient cough or suction the patient
  • reposition the patient 
4. The catheter may move back on own by: 
  • a sudden intense elevation in intrathoracic pressure 
  • patient repositioning 
5. If the pulmonary wedge pattern persists, observe the distance that the catheter is inserted by evaluating the black markings.  5. Each wide band represents 50 cm and each narrow band 10 cm from the distal tip. 
6. Gently aspirate the balloon port prior to withdrawal to ensure deflation. 6.
  • The balloon automatically deflates with disconnection of the syringe from the balloon gate. 
  • Prior to withdrawal, the balloon must in the deflated position to prevent injury to the pulmonary or tricuspid valves. 
  • The likelihood that the balloon would remain inflated if the gate is unlocked is remote, however, it should be evaluated. 
  • Only gentle aspiration is necessary to confirm that the balloon is deflated; vigorous aspiration can lead to balloon rupture by invaginating the balloon into the lumen of the wedge port. 
7. Slowly withdraw the catheter while continuously observing for a change in the waveform to the pulmonary artery position. As soon as a PA tracing is observed, stop withdrawing.  7. The catheter may only need a very slight withdrawal to return it to a PA position.
  • Following return of the pulmonary artery tracing, slowly inflate the balloon and assess the pulmonary artery wedge pressure. 
  • If it takes less than 1 cc to inflate the balloon, carefully withdraw the catheter  an additional .5 - 1 cm.
  • Recheck the pulmonary wedge.
8. When a spontaneous wedge pattern develops, the catheter is too distal.  The catheter needs to be withdrawn enough to ensure adequate blood flow continues around the catheter following balloon deflation.  When the catheter is optimally positioned, it should take 1 - 1.5 cc to produce a pulmonary wedge; smaller volumes suggest that the catheter is too distal.
9. Monitor waveform closely for right ventricular or spontaneous wedge tracing. 

If a right ventricular tracing is noted, withdraw the catheter to the right atrium as per procedure below. 

  • If the catheter is withdrawn too far, it could slip into the right ventricle. 
    • prompt withdrawal to the right atrium ensures that the catheter is "safe".
  • The catheter could return to a spontaneous wedge pattern, requiring further adjustment.
10. Notify the physician.  10. At the earliest opportunity, the physician should assess the catheter for placement.
11. Document in the clinical record.  11. To record event and intervention.
Procedure Rationale

Identify right ventricular tracing on monitor. 

The right ventricular waveform can be differentiated from the pulmonary artery waveform by the following criteria:

  • the PA and RV waveforms have the same systolic pressures but the RV has a much lower diastolic pressure (compare the hourly PA systolic/diastolic pressures - if the catheter slips into the right ventricle, the systolic will remain the same but the PA diastolic will fall)

  • the RV diastolic will be similar to the right atrial diastolic pressure (compare the suspected RV diastolic with the right atrial (CVP) diastolic

  • the rise in the RV pressure will be closer to the QRS than the rise in the pulmonary artery rise

  • the pulmonary artery tracing should have a dicrotic notch

  • ventricular arrhythmias may develop if the pulmonary artery catheter is in the right ventricle



1. The catheter can soften and coil backward so that the tip is sitting in the right ventricle. Irritation of the ventricular endocardium can result in ventricular arrhythmias. 

RV Small

Figure 1: Right ventricular tracing from a pulmonary artery catheter

PA Small

Figure 2: Pulmonary artery tracing from a pulmonary artery catheter

RV to PA

Figure 3: PA catheter advanced from right ventricle to pulmonary artery

  See also Edubriefs: 
Differentiating right ventricle and pulmonary artery
Procedure Rationale
2. Inflate the balloon and observe the monitor for a change to a pulmonary artery waveform.  2. Balloon inflation can facilitate flotation from the right ventricle to the pulmonary artery. A prompt change to a pulmonary "wedge" pattern indicates the catheter was likely in the right ventricle and floated back into the pulmonary artery.

If the catheter does not float into the pulmonary artery position, inflation of the balloon "rounds out" the tip of the balloon and decreases the irritation to the ventricular endocardium.

3. Attempt to have catheter spontaneously migrate to the pulmonary artery position.
  • Have patient cough or suction them.
  • Reposition the patient
  • A sudden intense rise in intrathoracic pressure may force the catheter to migrate with blood flow.
  • A change in the patient's position may facilitate movement into the pulmonary artery. 
  • Ensure balloon is deflated. 
  • Turn any infusions that are being administered via the injectate (blue), VIP (white) or Paceport (orange) lumens "OFF" and administer any critical infusions via the introducer side arm. 
  • Withdrawal of catheter with inflated balloon could cause injury to the tricuspid valve. 
  • When the tip is withdrawn to the right atrium, any proximal infusions will back up into the sleeve.  The patient may be without important infusions, therefore, critical infusions should be connected to the introducer until the catheter is repositioned. 
  • Carefully withdraw catheter while continuously monitoring the distal waveform. 
  • Withdraw until a right atrial tracing appears. 
  • Continue withdrawing for another 5 cm.
If necessary, the distal (yellow) lumen can be used as a CVP line for administration of IV fluids, once catheter tip location in the proximal right atrium has been confirmed by the waveform.
  • When the right atrial tracing initially appears, the catheter tip will be situated in the right atrium and may be close to the tricuspid valve. 
  • The tip of the catheter should be withdrawn to maintain a proximal placement to the atrial lumen.  This decreases the risk of endocardial injury from the catheter tip.
8.  Notify the physician as soon as possible. 8. For catheter repositioning. 
9. Document in the clinical record.  9. To record the event and intervention. 


Brenda Morgan, Clinical Educator: CCTC
Developed May 15, 1992
Last Update: March 23, 2010

Revised: March 23, 2013