Comparison of Morphine and Clonidine as Adjuvants in Paravertebral Block

General anesthesia (GA) has been considered as the gold standard for breast cancer surgery. The problem of postoperative pain as well as the high incidence of nausea and vomiting has led to the search for a better modality for pain management with fewer side effects. In the last few years, paravertebral block (PVB) has gained immense popularity either in combination with GA or by itself for the anesthetic management of patients undergoing breast surgery.

Paravertebral block in breast surgery.

This study aims to evaluate the efficacy and duration of postoperative analgesia provided by ultrasound (USG)-guided PVB with bupivacaine and morphine versus bupivacaine and clonidine in patients undergoing modified radical mastectomy (MRM).

In the study, 70 patients who were scheduled for MRM were enrolled and randomly divided into Group M (n = 35) and Group C (n = 35). Both groups received USG-guided PVB at T2-T3 after administering GA. Group M received 2 mg/kg 0.5% bupivacaine with 0.05 mg/kg morphine and Group C received 2 mg/kg 0.5% bupivacaine with 1 μg/kg clonidine in the block. Postoperatively, pain intensity was recorded using the visual analog scale (VAS) (0-10 scale) at 1, 2, 6, 18, and 24 h duration when patients were resting and during a standardized movement. Modified Post Anaesthesia Discharge Scoring System was assessed at 1, 2, 6, 18 and 24 h after surgery.

In this study conducted on 70 patients, VAS scores (both at rest and on movement) were found comparable at postoperative 1, 2, 6, 18, and 24 h (P > 0.05). There was no statistical difference in comparing postanesthesia discharging scoring in both the groups. No incidence of postoperative nausea and vomiting was seen in any group.

Morphine and clonidine in PVB are equally effective, and there is no superiority of one agent over the other. Hence, both drugs may be used with equal efficacy as adjuvants to bupivacaine in PVB for providing postoperative analgesia.