Serial changes in systolic blood pressure (A) and heart rate (B). On the left side of the panels, data are serial values for the first 20 measurements shown as mean and SD. Because the noninvasive blood pressure monitor took a variable time to start and complete each blood pressure measurement, tick values on the horizontal axis represent the sequential number of each measurement made with the monitor set to an automatic 1-min cycling time rather than exact chronological time. On the right side of the panels, bars show the area under the curve for the two groups (N = norepinephrine and P = phenylephrine) standardized for each patient by dividing by the number of data points recorded and shown as median and interquartile range. Comparison of the calculated values for standardized area under the curve showed that systolic blood pressure was similar between groups (P = 0.36), but heart rate was greater over time in the norepinephrine group versus the phenylephrine group (P = 0.039).