Comparison of Mepivacaine 2% and Isobaric Bupivacaine 0.5% Spinal Anesthetics for Total Knee Arthroplasty.

Spinal anesthesia is an option for patients during total knee arthroplasty (TKA) procedures. Spinal anesthesia can offer advantages and disadvantages to the patient's experience and outcomes. We conducted an evidence-based, quality improvement project comparing mepivacaine 2% and isobaric bupivacaine 0.5% and retrospectively assessed specific intraoperative and postoperative outcomes that were of interest to the staff at the hospital where the project was completed. Primary outcome measures of interest included intraoperative heart rate, blood pressure, vasopressor use, fluid resuscitation, postoperative pain scores, use of opioid analgesic medications, and time to ambulation after administration of the spinal anesthetic. Compared with patients receiving isobaric bupivacaine 0.5% (n = 30), patients receiving mepivacaine 2% (n = 30) had greater intraoperative hemodynamic stability (defined as heart rate and blood pressure maintained within 20% of baseline values) during the first 30 minutes after anesthetic administration (P < .05 for multiple time points). They also required less opioid medication for postoperative pain management (25 vs 50 mcg fentanyl) and were able to ambulate sooner after the procedure (mean [standard deviation], 452.2 [218.5] vs 681.0 [476.6] minutes; P = .006). In conclusion, mepivacaine 2% was the higher-performing local primary spinal anesthetic for patients undergoing TKA.