Our review revealed a great heterogeneity in definition , format , and values of what is considered a clinical ly relevant difference in pain in RCTs of analgesics , and st and ardizations are advisable
OBJECTIVE To describe the  pain decrease considered as clinical ly relevant when design ing a trial and reporting its results .
Clonidine Added to a Continuous Interscalene Ropivacaine Perineural Infusion to Improve Postoperative Analgesia: A Randomized, Double-Blind, Controlled Study
Although clonidine has been shown to increase the duration of local anesthetic action and prolong postoperative analgesia when included in single-injection nerve blocks , the only controlled investigation of the efficacy of this practice to improve analgesia for continuous perineural local anesthetic infusion failed to discern any clinical ly relevant benefits . For this study , we used a larger dose of clonidine in an attempt to improve analgesia . Patients ( n = 20 ) undergoing moderately painful orthopedic surgery of the shoulder received an  interscalene brachial plexus block ( 40 mL of mepivacaine 1.5 % , epinephrine 2.5 & mgr;g/mL , and clonidine 50 & mgr;g ) and a perineural catheter before surgery . After surgery , ropivacaine 0.2 % or ropivacaine 0.2 % plus clonidine 2 & mgr;g/mL was delivered via the catheter for 3 days ( basal rate , 5 mL/h ; patient-controlled bolus , 5 mL ; lockout , 1 h ) . Investigators and patients were blind to r and om group assignment . The primary outcome variable was design ated as the most intense pain during the day after surgery . Secondary end-points included additional pain scores , patient-controlled bolus doses , oral analgesic use , sleep quality , and catheter- or infusion-related complications . There were no statistically significant differences between groups for any of the variables investigated . We conclude that adding clonidine 2 & mgr;g/mL to a ropivacaine interscalene perineural infusion does not decrease breakthrough pain intensity the day after surgery . For the additional end-points , our negative findings are only suggestive of a lack of effect and require further study for verification
Our review revealed a great heterogeneity in definition , format , and values of what is considered a clinical ly relevant difference in pain in RCTs of analgesics , and st and ardizations are advisable
OBJECTIVE To describe the  pain decrease considered as clinical ly relevant when design ing a trial and reporting its results .