Investigation of efficacy of erector spinae plane block administered in different volumes on intraoperative opioid consumption and postoperative analgesia in breast surgery: Randomized, prospective, double-blind study.

Objectives: We investigated the efficacy of the erector spinae plane block, which has been proven to be effective in breast surgery, on intraoperative opioid consumption and postoperative analgesia when administered in different volumes with the same concentration of local anesthetic.

Methods: This study is designed as randomized, prospective, and double-blind. Seventy patients aged between 18-70 years, undergoing ASA I-III elective breast surgery, were included. Unilateral erector spinae plane block was achieved by administering 20 mL of 0.375% bupivacaine hydrochloride in 35 patients in Group I and 30 mL of 0.375% bupivacaine hydrochloride in 35 patients in Group II. The analgesic requirement of the patients was monitored with the surgical plethysmographic index throughout the surgery. Intraoperative and postoperative opioid consumption, rescue analgesic requirements in the first 24 hours, and NRS scores at the 10th minute, 1st hour, 6th hour, 12th hour, and 24th hour postoperatively were recorded.

Results: Both intraoperative and postoperative opioid consumptions were similar between groups (p>0.05). The number of involved dermatomes was significantly higher in Group II (p<0.05). No significant difference was found between postoperative NRS scores (p>0.05).

Conclusion: In elective breast surgery, erector spinae plane block administered at the same concentration in 20 or 30 mL volumes does not make a difference in opioid consumption and postoperative analgesia.