1. Tricuspid or pulmonary valve stenosis.
The catheter may be difficult or impossible to pass and may lead to a significant reduction in venous return during passage through the stenosed valve.

2. The presence of a prosthetic tricuspid or pulmonary valve.
The catheter may become entangled in the valve mechanism. The valve may then jam and / or the catheter become irremoveable.

3. Right atrial or right ventricular masses.
Tumour or thrombus may be dislodged by the catheter leading to pulmonary embolism.

4. Cyanotic heart disease.
Several issues are posed by patients with cyanotic heart disease which should be addressed before a catheter is used:

- By definition, pulmonary blood flow is reduced and therefore a flow-directed catheter is more likely to follow the bulk flow to the systemic side of the circulation.

- Mechanical anomalies (such as pulmonary stenosis or septal override) may make entry into the pulmonary artery difficult.

- The patient is at increased risk of systemic gas embolism. For this reason, CO2 must be used as the inflating gas for the balloon and scrupulous attention must be paid to de-airing all catheter lumens and administered fluids.

- Once in the pulmonary artery, the presence of the inflated balloon may further reduce pulmonary blood flow and increase right-to-left shunt.

- In Tetralogy of Fallot (Figure 1), pulmonary arterial catheterisation is often said to be specifically contraindicated because of the problems outlined above and the additional potential for infundibular spasm.

- The estimates of cardiac output and LVEDP derived from the catheter will be inaccurate.

5. Latex allergy.
The balloons of most manufacturers' catheters are latex and are therefore contraindicated in all patients with a history of latex allergy. Anaphylaxis in association with the use of a pulmonary artery catheter has been described ¹. A 'Latex Free' catheter has recently become available.

6. Previous pneumonectomy.
There are two vitally important considerations in the patient who has undergone previous pneumonectomy.

- First, the consequence of PA rupture in such a patient would almost certainly be fatal.

- Second, inflation of the catheter balloon might precipitate an unacceptable rise in pulmonary vascular resistance.

For these reasons, PA catheterisation is practically always contraindicated.

At the 'relative' end of the contraindication spectrum are:

1. A patient at risk of severe arrhythmias.
The risks of inducing a severe arrhythmia can be reduced if the precautions outlined in the section on cardiac arrhythmias are observed. It is often more appropriate to let the full effects of antiarrhythmic therapy develop before attempting to pass a pulmonary artery catheter in patients with extreme myocardial irritability. If it is imperative to use a PAC in a patient at high risk of arrhythmias, the following safeguards must be observed:

In the past it has been suggested that the presence of a left bundle branch block (LBBB) is a relative contraindication to PAC placement in case passage of the catheter precipitates complete heart block (CHB). In the large series reported by Shah ², CHB only occurred in 1 of the 113 patients with longstanding LBBB and in the series reported by Risk et al ³ none out of 41 patients developed CHB. Thus the 'prophylactic' use of transvenous pacing in such patients does not seem to be warranted.

In contrast, the presence AV or fascicular block of recent onset places the patient at high risk of CHB and transvenous pacing should be established in such patients before passage of a PAC. Under these circumstances it is wise to use a pacing catheter (in case the temporary wires are dislodged) and to have appropriate pacing equipment immediately available.

2. Anticoagulation.
Anticoagulation is both a relative contraindication to venepuncture and may also increase the risks of pulmonary artery rupture. - Profound anticoagulation is one of the indications for venous access via the basilic vein. If this route is chosen, the left-sided approach offers a less tortuous route for the catheter than the right.

3. Proposed pneumonectomy.
There are several reasons why proposed pneumonectomy is a relative contraindication to a PAC.

4. Attempted flotation during cardiopulmonary bypass.
If a catheter has been withdrawn before CPB, reflotation should not be attempted until the patient has been weaned from bypass. Attempted flotation during bypass is difficult because the bulk blood flow is into the cardiotomy reservoir and the catheter therefore tends to take this route. Obstruction of venous lines by PACs during bypass has been described on several occasions ^{5, 6}.

Atrial closure at the end of bypass also carries the risk of inclusion of the catheter in the atriotomy site ⁷ and for this reason it is preferable to refloat the catheter after the venous line has been removed and the atriotomy closed.

1. Gosgnach M; Bourel LM; Ducart A; Barre E; Viars P Pulmonary artery catheter balloon: an unusual cause of severe anaphylactic reaction. Anesthesiology, 83:220-1, 1995 Jul

2. Shah KB, Rao TL, Laughlin S, El-Etr AA A review of pulmonary artery catheterization in 6245 patients. Anesthesiology 61:271 - 275, 1984

3. Risk SC, Brandon D, D'Ambra MN et al Indications for the use of pacing pulmonary artery catheters in cardiac surgery. J Cardiothorac Vasc Anesth, 1992:275-279

4. Benumof JL, Saidman IJ, Arkin DB, et al: Where pulmonary artery catheters go: Intrathoracic distribution. Anesthesiology 46:336, 1977

5. Oyarzun JR; Donahoo JS; McCormick JR; Herman S Venous cannula obstruction by Swan-Ganz catheter during cardiopulmonary bypass. Ann Thorac Surg, 62(1):266-7 1996 Jul

6. Gilbert TB Scherlis ML Fiocco M Lowinger TA Pulmonary artery catheter migration causing venous cannula obstruction during cardiopulmonary bypass. Anesthesiology 1995 Feb, 82 [2]: 596- 7.

7. Pybus DA Personal observation. Unpublished

Last edited on: 13/11/2000