Erroneous continuous cardiac output by calibrated pulse contour analysis.

Pulse contour analysis techniques are used for beat-to-beat tracking of cardiac output in critically ill patients. However, an adequate pulse pressure waveform signal and identification of the appropriate (i.e. systolic) part of the waveform by the monitor are crucial for correct calculation of continuous cardiac output. We observed a case where the monitor failed to correctly identify the systolic part of the waveform during tachycardia thus giving false readings. We would like to emphasize the importance of visually checking the waveform for any irregularities that may cause erroneous calculations before initiating a therapy based on these values. One advantage of the system used here is that the part of the pressure curve used for analysis is automatically indicated.