Perineural injection or intravenous infusion of dexmedetomidine in ultrasound-guided erector spinae plane block combined with serratus anterior plane block for analgesia after thoracoscopic surgery : a randomized controlled study

BACKGROUND: This research aimed to evaluate the analgesic effect of perineural injection or intravenous infusion of dexmedetomidine in ultrasound-guided erector spinae plane block (ESPB) combined with serratus anterior plane block (SAPB) for patients undergoing thoracoscopic surgery. METHODS: In this prospective, double-blind, randomized controlled trial, seventy-five patients scheduled for thoracoscopic surgery were randomly divided into the control group (group R: 40 ml of 0.375% ropivacaine for ESPB combined with SAPB and 40 ml of 0.9% NaCl for intravenous infusion), the intravenous infusion of dexmedetomidine group (group RDiv: 40 ml of 0.375% ropivacaine for ESPB combined with SAPB and 40 ml of 0.9% NaCl containing 1 µg/kg dexmedetomidine for intravenous infusion), and the perineural injection of dexmedetomidine group (group RD: 40 ml of 0.375% ropivacaine containing 1 µg/kg dexmedetomidine for ESPB combined with SAPB and 40 ml of 0.9% NaCl for intravenous infusion). The primary outcome was the duration of effective analgesia, defined as the time from the onset of nerve blocks to the first demand for patient-controlled analgesia. Secondary outcomes included postoperative opioid consumption, rescue analgesia, numeric rating scale (NRS) scores, adverse effects and quality of recovery. RESULTS: Compared with group R and group RDiv, the duration of effective analgesia in group RD was significantly prolonged (1313.8 ± 372.8 vs. 844.5 ± 285.2 vs. 943.0 ± 417.2 min, P < 0.05), opioid consumption and the number of patients who required rescue analgesia were significantly reduced (P < 0.05), and NRS scores at rest and on movement at 24, 36 and 48 h were all significantly reduced (P < 0.05). Group RD exhibited a reduced incidence of postoperative nausea and vomiting (P < 0.05), along with improved quality of recovery-15 score at 24 h postoperatively (P < 0.05). CONCLUSIONS: Perineural injection of dexmedetomidine in ultrasound-guided erector spinae plane block combined with serratus anterior plane block could still significantly prolong the duration of effective analgesia after thoracoscopic surgery, reduce opioid consumption, and improve the occurrence of adverse effects, thereby improving early-term recovery. However, the same clear benefits were not observed with intravenous dexmedetomidine. TRIAL REGISTRATION: The study was registered at Chinese Clinical Trial Registry (https//www.chictr.org.cn) with the number ChiCTR2400088052 on 08/09/2024.