Efficacy of dexmedetomidine as an adjuvant in paravertebral block in breast cancer surgery

Abstract

This study evaluated the analgesic efficacy of dexmedetomidine in combination with bupivacaine for single-shot paravertebral block (PVB) in patients undergoing major breast cancer surgery. This prospective, randomized double blind study was conducted in 45 ASA I/II/III females, aged ≥18 years, undergoing modified radical mastectomy or breast conservation surgery with axillary lymph node dissection. Patients in group PB (paravertebral–bupivacaine) received PVB with 0.5 % bupivacaine 0.3 ml/kg with 1 ml normal saline; group PBD (paravertebral–bupivacaine–dexmedetomidine) received PVB with 0.5 % bupivacaine 0.3 ml/kg and dexmedetomidine 1 μg/kg in a volume of 1 ml; and group C (control) patients were given a sham block (a subcutaneous injection with 2 ml normal saline) before receiving general anesthesia (GA). All patients received analgesia by fentanyl intraoperatively and morphine patient-controlled analgesia postoperatively. The control group patients required more intraoperative fentanyl than the other two groups. Patients receiving dexmedetomidine had lower morphine consumption (p < 0.001), pain scores and incidence of postoperative nausea/vomiting (p = 0.011); longer time to first analgesic request; earlier time to mobilize; and better satisfaction scores. Heart rate and blood pressure values during the intraoperative period were also lower at many time points in this group. However, the incidence of hypotension and bradycardia were statistically similar in all groups. PVB using dexmedetomidine 1 µg/kg added to 0.5 % bupivacaine in patients undergoing major breast cancer surgery under GA provides analgesia of longer duration with decreased postoperative opioid consumption and lower incidence of nausea/vomiting compared to PVB with bupivacaine alone or no PVB.