Epinephrine 4 μg/mL Added to a Low-Dose Mixture of Ropivacaine and Fentanyl for Lumbar Epidural Analgesia After Total Knee Arthroplasty

Abstract

Epinephrine 2 microg/mL added to a local anesthetic-opioid mixture has been found to improve postoperative continuous epidural analgesia at the thoracic (TEA) but not at lumbar (LEA) level. Therefore, we studied whether a higher dose of epinephrine could improve LEA. Patients received LEA comprising of ropivacaine 1.8 mg/mL and fentanyl 3 microg/mL either without (group RF, n = 32) or with epinephrine 4 microg/mL (group RFE, n = 31) for 2 days after total knee arthroplasty. Rescue pain medication consisted of epidural top-ups (study mixture) and parenteral oxycodone. Total amounts of epidurally administered drugs were significantly higher in group RFE. Otherwise, the groups did not differ significantly regarding pain relief and side effects. As part of the multimodal pain treatment used, the epidural adjuvant epinephrine 4 microg/mL (12-32 microg/h) did not improve LEA after total knee arthroplasty.