The Efficacy of Programmed Intermittent Epidural Bolus for Postoperative Analgesia after Open Gynecological Surgery: A Randomized Double-Blinded Study

Figure 3

Comparison of the programmed intermittent epidural bolus (PIEB) and continuous epidural infusion (CEI) groups in terms of numeric rating scale (NRS) of pain 3, 24, and 48 hours after surgery. The data are shown as medians (lines in the boxes), 25th and 75th quartiles (bottom and top of the boxes, resp.), and the lower and upper outlier thresholds (the ends of the whiskers on the boxes). The lower outlier threshold was the 25th percentile minus 1.5 × the interquartile range (IQR; 75th quartile minus 25th quartile) while the upper outlier threshold was the 75th percentile plus 1.5 × the IQR. Significant () differences between the PIEB and CEI groups, as indicated by Mann–Whitney tests.