A Comparative Study of Placebo Versus Opioid-Free Analgesic Mixture for Mastectomies Performed Under General Anesthesia Along With Erector Spinae Plane Block.

Background and objectives Breast cancer is the most frequent cancer among women, globally. Postoperative pain after mastectomy not only causes slow recovery and prolonged hospital stay but can also increase the risk of chronic pain. For patients undergoing breast surgery, effective perioperative pain management is required. Various approaches have been introduced to overcome this, such as opioids, non-opioid analgesics, and regional blocks. The erector spinae plane block is a new regional anesthesia technique used in breast surgery to provide adequate intraoperative and postoperative analgesia. Opioid-free anesthesia is a multimodal analgesia technique that does not use opioids and thus prevents opioid tolerance after surgery. This study aims to investigate whether administering an opioid-free analgesic mixture lowers the pain score and the need for analgesics during and after surgery. Material and methods In this randomized prospective comparative clinical study, 66 patients of the American Society of Anesthesiologists (ASA) psychological status (PS) class 1 and 2, aged 18 to 80, were included. Group M received erector spinae plane block + general anesthesia + opioid-free analgesic mixture (1 mcg/cc dexmedetomidine + 1 mg/cc ketamine + 100 mg/cc magnesium sulfate prepared in a 20 ml syringe). Group N received erector spinae plane block + general anesthesia + 20ml of normal saline infusion. The primary outcome was to assess pain scores in the perioperative period. The secondary outcomes were to compare the time for the first rescue analgesia requirement perioperatively, intraoperative hemodynamic profile, and postoperative patient satisfaction. A p<0.05 was considered to be statistically significant. Results All patients were females undergoing modified radical mastectomy or breast conservative surgery + axillary sampling + latissimus dorsi flap reconstruction. The visual analog scale (VAS) scores were less than or equal to 3 in zero, first, and second hours postoperatively in both groups. The pain was moderate i.e., less than 4 in almost all time intervals in both groups. Group M had a better intraoperative hemodynamic profile, including mean arterial pressure and heart rate when compared to group N. In group M, the time of request for rescue analgesia was 726.67±390.99 minutes, while it was 468±278.79 minutes in group N. The total analgesic requirement was less in group M than in group N, but this was not statistically significant. Conclusion Multimodal analgesia with erector spinae plane block and opioid-free analgesic mixture provides effective perioperative analgesia and a better intraoperative hemodynamic profile in patients undergoing breast cancer surgery under general anesthesia.