Figure 32-6 Underdamped arterial pressure waveform. Systolic pressure overshoot and additional small, nonphysiologic pressure waves (arrows) distort the waveform and make it hard to discern the dicrotic notch (boxes). Digital values displayed for direct arterial blood pressure (ART 166/56, mean of 82 mm Hg) and noninvasive blood pressure (NIBP 126/63, mean of 84 mm Hg) show the differences in pressure measurement that arise because of an underdamped arterial pressure waveform. (Redrawn from Mark JB: Atlas of Cardiovascular Monitoring. New York, Churchill Livingstone, 1998, Fig. 9-4.)