title: Epinephrine does not prolong the analgesia of 20 mL ropivacaine 0.5% or 0.2% in a femoral three-in-one block.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Anesthesiology, Pharmacology and Surgical Intensive Care, and Clinic of Orthopedic Surgery, University Hospitals, Geneva, Switzerland. Anne.Weber@hcuge.ch
authors.forename: A
authors.initials: A
authors.lastname: Weber
authors.forename: R
authors.initials: R
authors.lastname: Fournier
authors.forename: E
authors.initials: E
authors.lastname: Van Gessel
authors.forename: N
authors.initials: N
authors.lastname: Riand
authors.forename: Z
authors.initials: Z
authors.lastname: Gamulin
mesh_terms: D000082:Acetaminophen / Q000008:administration & dosage; D000368:Aged; D000577:Amides / Q000494:pharmacology*; D016058:Analgesia, Patient-Controlled; D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage; D000701:Analgesics, Opioid / Q000008:administration & dosage; D000768:Anesthesia, General / Q000379:methods; D000779:Anesthetics, Local / Q000494:pharmacology*; D019645:Arthroplasty, Replacement, Knee; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004347:Drug Interactions; D004837:Epinephrine / Q000494:pharmacology*; D005260:Female; D005267:Femoral Nerve / Q000187:drug effects*; D006801:Humans; D008297:Male; D009020:Morphine / Q000008:administration & dosage; D009407:Nerve Block / Q000379:methods*; D000077212:Ropivacaine; D012584:Sciatic Nerve / Q000187:drug effects
chemical_list: D000577:Amides; D018712:Analgesics, Non-Narcotic; D000701:Analgesics, Opioid; D000779:Anesthetics, Local; D000082:Acetaminophen; D009020:Morphine; D000077212:Ropivacaine; D004837:Epinephrine