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*Department of Anesthesiology, Pharmacology and Surgical Intensive Care, and
Clinic of Orthopedic Surgery, University Hospitals, Geneva , Switzerland
Address correspondence and reprint requests to Anne Weber, Department of Anesthesiology, Pharmacology and Surgical Intensive Care, University Hospitals, 1211 Geneva 14, Switzerland. Address e-mail to Anne.Weber{at}hcuge.ch
We tested the effect of epinephrine added to 20 mL ropivacaine 0.5% and 0.2% on postoperative analgesia via a femoral catheter after total knee replacement. Forty-one patients undergoing total knee replacement under combined peripheral block/general anesthesia were randomly allocated to two groups. After insertion of a femoral catheter, 21 patients in the Ropivacaine-Epinephrine (ROPI-EPI) group received 20 mL ropivacaine 0.5% plus epinephrine 1:200,000, whereas 20 patients in the Ropivacaine group (ROPI) received 20 mL plain ropivacaine 0.5%. Thereafter, a sciatic block with 30 mL bupivacaine 0.5% plus epinephrine 1:200,000 was performed in all patients, followed by general anesthesia. After surgery, patient-controlled analgesia (PCA) with ropivacaine 0.2% plus epinephrine 1:200,000 for Group ROPI-EPI and plain ropivacaine 0.2% for Group ROPI was available via the femoral catheter (200 mL ropivacaine 0.2% ± epinephrine, bolus 20 mL, lockout 120 min). The patients were instructed to use PCA when the knee pain score was >3 cm. The interval between the initial ropivacaine injection and the first PCA injection determined the duration of 20 mL ropivacaine 0.5% ± epinephrine, whereas the interval between the first and second PCA injection determined the duration of 20 mL ropivacaine 0.2% ± epinephrine. The average duration of ropivacaine 0.5% was 657 ± 345 min for the ROPI-EPI group and 718 ± 423 min for the ROPI group (NS), whereas for ropivacaine 0.2%, the average duration was 409 ± 245 min for the ROPI-EPI group and 419 ± 339 min for the ROPI group (not significant). We conclude that epinephrine does not influence the duration of analgesia of the ropivacaine concentrations investigated.
IMPLICATIONS: We evaluated the effect of epinephrine on the duration of analgesia of 20 mL ropivacaine 0.5% or 0.2% injected in femoral three-in-one block for pain relief after total knee replacement. Our results show that epinephrine does not alter the duration of analgesia of the two solutions investigated.
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