The Effect of Ultrasound-Guided Erector Spinae Plane Block Combined with Dexmedetomidine on Postoperative Analgesia in Patients Undergoing Modified Radical Mastectomy: A Randomized Controlled Trial

INTRODUCTION: One of the most common malignancies in women worldwide is breast cancer. Erector spinae plane block (ESPB) can reduce pain after modified radical mastectomy for breast cancer. The duration of nerve block analgesia is limited if local anesthetic agents are used alone. The purpose of this study was to evaluate the effect of dexmedetomidine on postoperative analgesia during a single injection of local anesthetics. METHODS: In this double-blind, randomized study, 60 female American Society of Anesthesiologists (ASA) I–II patients undergoing modified radical mastectomy were randomized into two groups: ultrasound (US)-guided ESPB with 30 mL of 0.33% ropivacaine (group R) and US-guided ESPB with 30 mL of dexmedetomidine plus 0.33% ropivacaine (group DR). US-guided ESPB at the T3 vertebral level was performed preoperatively in all patients. The indicators were 1-, 6-, 12-, 24-, and 48-h visual analog scale (VAS) pain scores after surgery in the resting state and at 90-degree shoulder abduction. Other measures were a comparison of intraoperative sufentanil and remifentanil, postoperative nausea and vomiting (PONV), flurbiprofen consumption, the lengths of post-anesthesia care unit (PACU) stay and hospital stay, postoperative bradycardia, and hypotension. RESULTS: The VAS pain score was lower in group DR than group R at any time in the resting state, except at 1 h after surgery. The VAS pain score was lower in group DR than group R at 12 and 24 h in an active state after surgery (P < 0.05 for each time interval). The intraoperative dosages of remifentanil and sufentanil in group DR were lower than that in group R. The postoperative dosage of flurbiprofen in group DR was lower than that in group R (P = 0.038). The lengths of PACU stay were longer in group DR than in group R. No significant difference was found in PONV and hospital stay between the two groups. No sinus bradycardia or hypotension after surgery occurred in the two groups. CONCLUSIONS: Dexmedetomidine as an adjunctive to ESPB can effectively relieve pain and significantly reduce the need for opioids during modified radical mastectomy for breast cancer. TRIAL REGISTRATION: The study was registered in the Chinese Clinical Trial Registry (ChiCTR2000031134, principal investigator: Yao Lu, date of registration: 2020-3-22).