Troubleshooting the insertion of the pulmonary artery catheter

Practical guide: PA catheter insertion problems and their solutions

It won't advance: stuck in the SVC or the RA. If there is enough catheter length in the patient, but it just won't go in the RV…

• It may be tricuspid regurgitation.  
  • The jet of blood regurgitating from the right ventricle may be pushing the catheter out of the RV with each contraction.
  • The solution: fill the balloon with 1.5ml of normal saline, and lay the patient left side down.
  • Gravity should guide the now heavier balloon into the right ventricle.
• Or, it may be a persistent Chiari network (Safwat, 2001). This is  a network of  fibrous strands attached to the edges of the eustachian and/or thebesian valves,   persisitng into adulthood after incomplete resorption of the embryologic right valve of the sinus venosus.
  • In this case, you are better off passing a deflated catheter (i.e. inflating a balloon only when you are well and tryly in the RV), as it will be easier to penetrate those fibrous strands.
• Or, it may be a left SVC (Lai et al, 1998)
  • Passing a left IJ PA catheter in this scenario may be difficult
  • You might need to catheterise through the femoral or right IJ

It won't advance: stuck in the RV

• You have a good RV waveform, but it won't go into the PA…
• It's probably coiled up in the RV. This can happen in patients with pulmonary hypertension or a big dilated RV, particularly where its contractility is very poor.
  • Withdraw it to the SVC, and try again.
  • Sit the patient up, and/or position them let side up - the inflated balloon should drag the catheter towards the pulmonic valve
  • Use a slow continuous motion – no rapid thrusts. The RV may be dilated because of MI, and the wall might be particularly fragile. 
  • Time your insertion push with periods of expiration (for a mechanically ventilated patient) or inspiration (for a spontaneously breathing patient)

It won't advance, and it looks arterial, but it is not deep enough

• The catheter is giving what looks like an arterial waveform, but it is so preposterously shallow (about 30cm in) that there is absolutely no way that it could be in the pulmonary artery.
• Congratulations, you have probably cannulated the coronary sinus. Awad et al (2011) reported on this, and even produced a few methods of confirming this position (eg. taking a blood gas will reveal a very low oxygen saturation).
  • The solution is to withdraw the catheter by about 10cm, and then try again. It won't happen again: the coronary sinus is a very small target and should be difficult to hit. 
  • If it keeps happening, the patient may have an anomalous dilated sinus, or some other congenital weirdopathy. One preventative solution is to reposition the patient right side up, and then try again.

I deflated the balloon, but it looks wedged again.

• Your catheter tip has migrated to a more distal artery; it is so narrow that the catheter itself no occludes the artery lumen without the need for balloon inflation.
• You cant leave it like that, because it will result in a pulmonary infarction.
•  Withdraw the tip a few centimeters and gently attempt to wedge again.

My patient now has an arrhythmia.

• You have irritated the endocardium.
• Just relax, it will go away very shortly.
• Most likely, removing the catheter entirely may not be an option (otherwise why did you even insert it). However, if 

My patient has complete heart block.

• You have now irritated the endocardium in a way which somehow disrupted AV nodal conduction.
• Withdraw the catheter. Get the pacing pads You need to give this patient some pacing while you wait.
  • If you are lucky, it will go away after a brief period of pacing.
  • If you are unlucky, you have injured the AV node and the patient is in for a prolonged period of transvenous pacing,

Where is the catheter tip on Xray?

• On the Xray, the tip should appear 3 -5 cm from the midline, no more than 2cm from the hilum.
• If you plan on measuring the wedge pressure, it should be inferiorr to the LA position (eg. in the film above, its around the lower LA border). Of course, if you do not care about the wedge pressure (as these days nobody does), this is not essential. 

The catheter tip needs to be in Wests Zone 3.
Is it in the right position?

• To maintain a column of blood between the pressure transducer and the left atrium, the balloon has to be below the atrium (otherwise, no column, duh.) This means you have to send the catheter tip into Wests Zone 3 when you are floating it .
• This should happen naturally because Wests Zone 3 normally enjoys higher blood flow.
  • But that may not be the case in a patient ventilated with positive pressure (blood is pushed around into all zones) or some other reason for a high intrathoracic pressure;
  • To maximize your chance of sending the catheter tip to Zone 3, one may artificially increase the blood flow to that zone by turning the patient on one side.

How can you tell that it is in the third zone?

• On lateral CXR, the tip of the catheter is at or below the left atrium
• Respiratory variation of PAOP is < 50% of the static airway pressure (peak – plateau)
• Change the PEEP: PAOP changes by 50% of the change in PEEP
• The PAWP is less than the PA diastolic pressure
• The PAWP contour has recognizable a and v waves; in Zones 1 and 2 it is unnaturally smooth.

You can also use peripheral ABG and wedge ABG parameters.

• Wedge PO₂ minus Arterial PO₂ = 19mmHg
• Arterial PCO₂ minus Wedge PCO₂ = 11mmHg
• Wedge pH minus Arterial pH = 0.008