Fig. 3From: Efficacy of programmed intermittent bolus epidural analgesia in thoracic surgery: a randomized controlled trialPCA data after surgery. Data are presented as median [lower–upper quartiles]. The Mann–Whitney U test was used for comparison of categorical variables. *P < 0.05. PCA: patient-controlled analgesia, PIB: programmed intermittent bolus, CEI: continuous epidural infusionBack to article page