Diabetic Neuropathy and Minimum Effective Anesthetic Concentration of Mepivacaine for Axillary Brachial Plexus Block: A Prospective Observational Study.

Nerves in patients with diabetic neuropathy (DN) show increased susceptibility to local anesthetics, potentially requiring a decreased dose. We investigated whether the minimum effective anesthetic concentration (MEAC) of mepivacaine for successful axillary block is lower in patients with DN than in those without. This prospective observational study included patients with DN (n = 22) and without diabetes (n = 22) at a tertiary care center. Patients received an ultrasound-guided axillary block with 30 mL of mepivacaine for anesthesia. The mepivacaine concentration used in each patient was calculated using Dixon's up-and-down method. A block was considered successful if all four sensory nerves had a score of 1 or 2 within 30 min with no pain during surgery. The primary outcome was the MEAC of mepivacaine, and the secondary outcomes included the minimal nerve stimulation intensity for the musculocutaneous nerve and the occurrence of adverse events. The MEAC50 was 0.55% (95% CI 0.33-0.77%) in patients without diabetes and 0.58% (95% CI 0.39-0.77%) in patients with DN (p = 0.837). The MEAC90 was 0.98% (95% CI 0.54-1.42%) in patients without diabetes and 0.96% (95% CI 0.57-1.35%) in patients with DN (p = 0.949). The stimulation threshold for the musculocutaneous nerve was significantly different between groups (0.49 mA vs. 0.19 mA for patients with vs. without diabetes; p = 0.002). In conclusion, the MEAC of mepivacaine for a successful axillary block is not lower in patients with DN.

A Randomized Comparison of Multimodal Analgesia and Fentanyl-Based Patient-Controlled Analgesia in Women Undergoing Robot-Assisted Bilateral Axillary Breast Approach Thyroidectomy.

Opioid-free multimodal analgesia (MMA) emerges as a preferable approach for postoperative pain management compared to opioid-based patient-controlled analgesia (PCA) in robot-assisted bilateral axillary breast approach thyroidectomy, a procedure commonly undergone by young female patients. We compared the analgesic efficacy and other recovery profiles between MMA and PCA. In total, 88 female patients were administered fentanyl-based PCA or the combination of lidocaine continuous infusion and nefopam injection before recovery from general anesthesia. The visual analog scale score of postoperative pain was assessed at the post-anesthesia care unit and at 6, 12, and 24 h after the termination of surgery. Postoperative nausea and vomiting (PONV), rescue analgesic and anti-emetic agents, recovery profiles, and adverse events were also compared. The median numeric rating scores on postoperative pain at 6 h after recovery from general anesthesia were three in both groups, with no significant difference between the groups at any time point. The PONV incidence was significantly higher in the PCA group than in the MMA group. The combination of systemic lidocaine infusion and nefopam injection has an analgesic effect equivalent to that of fentanyl-based PCA without PONV.