Fig. 2From: Patient-controlled intravenous analgesia with opioids after thoracoscopic lung surgery: a randomized clinical trialComparison of NRS pain scores and morphine requirements within 3Â days after surgery among three groups. NRS, numerical rating scale; POD, postoperative day. Top and bottom of boxes indicate interquartile range; centerlines indicate medians; whiskers indicate range (minimum to maximum)Back to article page