Differentiating Right Ventricle and Pulmonary Artery Waveforms

Question:

I think that the tip of my pulmonary artery catheter is displaying a Right Ventricular waveform.  What clues would help validate a right ventricular tracing?

Obtain a tracing of the right atrial, right ventricle, pulmonary artery and pulmonary wedge pressure tracing during insertion (you can retrieve these from the full disclosure, hemodynamic option at the central station). This should be posted to the chart to provide future reference.

At the start of each shift, post a tracing of the pulmonary artery tracing so that you have it for comparison in the event that your waveform should change.

If you observe a waveform that you suspect may be right ventricle, the following characteristics can support your assumption:

• A right ventricle waveform will appear taller than the previous pulmonary artery tracing (if measured on the same scale).

• The systolic pressure of a right ventricular tracing will be the same as the pulmonary artery pressure, but the diastolic right ventricle pressure will be lower than the pulmonary artery diastolic.  Look at your graphic record to see if the diastolic pressure has dropped without a change in the systolic pressure (very suspicious for RV placement)

• Obtain a right atrial pressure from the blue (proximal injectate) port of the PA catheter. If the tip of the catheter is in the right ventricle, the right atrial diastolic pressure will be almost the same as the right ventricle (the right atrial and right ventricle pressure equilibrate at the end of diastole).

• Compare the new waveform to the baseline pulmonary artery waveform obtained at insertion.  Take note of the timing relationship between the QRS and the upstroke of the pressure tracing. The rise of the RV pressure is closer to the QRS than the rise of the pulmonary artery pressure (RV pressure rises in order to open the pulmonary valve, the pulmonary artery pressure increases AFTER the valve opens and the ventricle ejects blood into the pulmonary circuit)

• A waveform change accompanied by new ventricular ectopic beats suggests that the tip of the catheter might be in the right ventricle. If a patient suddenly develops ventricular tachycardia and RV placement is suspected, the catheter should be withdrawn until the tip reveals a right atrial tracing

Important Point: 

• If the PA catheter is withdrawn so that the tip of the catheter is located within the right atrium (e.g., to manage ventricular ectope induced by RV placement), the proximal injectate (blue) or proximal infusion (white) ports may be displaced to terminate within the introducer or even the sheath. Both situations can result in fluid infusion into the sheath, with the loss of medication.

• The safest location for the delivery of vasoactive drugs is the introducer as it is independent of any changes in PA catheter position.

Show me the contrast between Right Ventricle and Pulmonary Artery Waveforms.