Effect of lidocaine on acute pain after modified radical mastectomy: a secondary analysis of a randomized trial.
Postoperative pain is a common concern for patients undergoing modified radical mastectomy (MRM) for breast cancer. Intravenous lidocaine may alleviate acute postsurgical pain. This study aimed to evaluate the analgesic effect of lidocaine in patients receiving sevoflurane or propofol maintenance anesthesia. This study is a secondary analysis of a randomized controlled trial evaluating the effect of lidocaine on postoperative outcomes. One hundred patients scheduled for MRM were randomized into four groups ( = 25 per group): sevoflurane (S), sevoflurane plus lidocaine (SL), propofol (P), or propofol plus lidocaine (PL). The primary outcome was the area under the curve (AUC) of the numerical rating scale (NRS) score at rest and during movement within 24 h postoperatively, while secondary outcomes included resting and active NRS within 24 h postoperatively, changes in early inflammatory markers (IL-6, IL-1 β, TNF-α, NF-κ B), consumption of anesthetics and analgesics, adverse events, and patient satisfaction. Compared with their respective control groups, lidocaine infusion in Groups SL and PL significantly reduced the resting and active AUC for NRS score at 24 h postoperatively (S vs. SL, < 0.001; P vs. PL, < 0.001) and yielded lower resting and active NRS scores at 3, 6, and 12 h after surgery (all < 0.001). No significant intergroup differences were observed in perioperative immune cell counts. However, postoperative serum levels of IL-6, IL-1 <, TNF-α, and NF-κB activity were significantly lower in the lidocaine groups (SL and PL) than in the controls (S and P). The consumption of anesthetics and analgesics, incidence of adverse events, and patient satisfaction within 24 h were comparable among the four groups. Intraoperative intravenous lidocaine infusion reduced acute postoperative pain, attenuated the early systemic inflammatory response in MRM patients. These benefits were independent of the maintenance anesthetic used (sevoflurane vs. propofol). However, given the multiple confounding factors that may affect the results of this study due to its design, further randomized controlled trials are required to confirm causality and assess long-term clinical and mechanistic outcomes. ChiCTR2300068563 (registered February 23, 2023).