Efficacy of Dexmedetomidine vs Morphine as an Adjunct in a Paravertebral Block with Bupivacaine in Postoperative Analgesia Following Modified Radical Mastectomy

Objective To observe the efficacy of dexmedetomidine vs morphine as an adjunct in a paravertebral block (PVB) with bupivacaine in postoperative analgesia following modified radical mastectomy. Study design This was a randomized controlled trial performed from June 2018 to August 2019 in the Department of Anesthesia, Bakhtawar Amin Medical and Dental College, Ch. Pervaiz Ellahi Institute of Cardiology, Multan, Gurki Hospital, Services Institute of Medical Sciences, and Sheikh Zayed Hospital, Lahore. Methodology Seventy-eight patients were equally divided into group M, which received morphine (3 mg) and group D, which received dexmedetomidine (1 µg/kg), along with 20 cc 0.25% bupivacaine, for PVB. The primary outcome included morphine requirements in the post-anesthesia care unit (PACU). Secondary outcomes included the quality and duration of analgesia, intraoperative doses of fentanyl and propofol, postoperative doses of diclofenac required, postoperative nausea and vomiting (PONV), and the Ramsey sedation score. Data were entered into SPSS version 23 (IBM Corp., Armonk, NY) and analyzed by applying the independent t-test, Mann Whitney U-test, and the chi-square test or Fischer’s exact test, as appropriate. P≤0.05 was considered statistically significant. Results The mean time for the first analgesic administration was much shorter in group D as compared to group M (p<0.001). The average doses of ephedrine and morphine used were higher in group D (p-value 0.033 and 0.013, respectively). In the PACU, 33.3% of group D patients as compared to 12.8% of group M patients needed morphine (p=0.032). Postoperatively, diclofenac consumption was higher in group D (p<0.001). Postoperative pain was lower and sedation was higher in group M (p<0.05). Conclusion As an adjunct to bupivacaine in PVB for MRM, morphine is superior to dexmedetomidine.