Central venous pressure (CVP) monitoring is accurate with multilumen, single-port, and tunneled catheters.1,2 When the ability to use separate lumens for CVP measurement and fluid administration is limited (e.g., only a single functioning lumen), the line may be used for both purposes simultaneously. The image shows an artifact in the CVP waveform appearing as square waves that occur at regular intervals in Panel A. The waveform could be misinterpreted as respirophasic variation, given that it occurs at regular intervals similar to the respiratory rate and end-tidal carbon dioxide waveform. Instead, the CVP tracing was caused by a “continuous” medication pump infusion attached distal to the transducer of a single lumen CVP catheter accessed via a buried port. After stopping the infusion pump, the native CVP tracing is shown in Panel B. To confirm the pump as the culprit of this observation, the pump was then restarted at a different infusion rate (Panel C).
Infusion pumps use different mechanisms to achieve a “continuous” fluid dispensation. In our situation, the solution was delivered at pulsed regular intervals rather than by truly continuous flow, creating the square CVP waveform that could be misinterpreted. Linear peristaltic pumps have also been reported to cause a CVP tracing that appears as an electrocardiography lead showing atrial fibrillation.3 Whenever an unexpected or unusual CVP waveform is displayed, we recommend isolating the transducing line from potential sources of error that could lead to incorrect treatments.
Competing Interests
The authors declare no competing interests.
