Background and Goal of Study: We hypothesized that thoracic continuous paravertebral block with ropivacaine and clonidine, as adjuvant, could improve acute postoperative pain management compared to local anaesthetic alone, during first 24h post-procedure in radical mastectomy patients. 
Materials and Methods: 74 ASA I-III women, candidates to elective radical mastectomy under general anaesthesia, participated in this prospective randomized double-blind study. Prior to surgery, a catheter prepared for postoperative continuous infusion was inserted in T4 paravertebral space in all patients. The patients were randomly allocated to two groups: group S (n=38) with continuous thoracic paravertebral block performed with a bolus of 0.3ml/kg 0.2% ropivacaine followed by 0.1ml/kg/h of local anaesthetic added with 1µg/ml clonidine and, respectively group C (n=36) treated according to the same protocol without clonidine. For postoperative analgesia during study period both groups received PCA with iv morphine.
The primary endpoints were the intensity of postoperative pain (VAS) evaluated at 2, 4, 8, 12, 24h and supplemental opioid requirements.
The incidence of sedation, nausea vomiting episodes, complications associated to the paravertebral block, hemodynamic parameters and patient satisfaction were documented too, as secondary endpoints. Mann-Whitney test and χ2 test were used as statistics (p< 0.05).
Results and Discussion: Demographic data were similar in both groups. The postoperative pain control was statistically superior in group S during study period (p< 0.05). The need for supplemental opioid administration was significantly lower in group S as compared to group C (p< 0.05). The number of patients free from sedation and nausea vomiting during first 24h postoperatively was significantly higher in group S (p< 0.05). Hemodynamic parameters were comparable in both groups. No complications attributed to the paravertebral block were detected. Regarding patient satisfaction, the number of subjects that rated their early postoperative analgesia as very satisfactory was significantly higher in group S, too (p< 0.05).
Conclusion(s): Clonidine added to 0.2% ropivacaine in continuous thoracic paravertebral block resulted in significant clinical advantages compared to local anaesthetic alone in terms of better pain control with less adverse events during first 24h postoperatively after radical mastectomy.

The analgesic efficacy of continuous thoracic paravertebral block with clonidine added to ropivacaine early postoperatively, after radical mastectomy