title: Skin blood flow after intradermal injection of ropivacaine in various concentrations with and without epinephrine evaluated by laser Doppler flowmetry.
abstract: OBJECTIVE
  Skin blood flow changes after intradermal injection of ropivacaine in various concentrations with or without epinephrine were investigated using laser Doppler flowmetry.
  
  
  METHODS
  Twenty-three non-smoking, healthy, young male volunteers participated. Four test sites were used on each forearm (volar surface) in a randomized, double-blind study. Recordings were made at 20, 40, 60, and 90 minutes after intradermal injection (0.1 ml, 30-gauge needle). Injections of saline and 1% lidocaine and an untreated area served as controls. In Series 1, various concentrations of ropivacaine (1%, 0.5%, 0.375%, 0.125%, and 0.063%) were injected.
  
  
  RESULTS
  The data from this series showed a dose-response relationship: 1% ropivacaine provoked an increase in skin blood flow similar to saline; 0.5% and weaker concentrations of ropivacaine showed a reduction in flow compared to saline, this being more pronounced with the weakest solutions (0.125% and 0.063%). In Series 2, injection of 1:200,000 (5 micrograms/ml) epinephrine alone and injections of ropivacaine in various concentrations (1%, 0.5%, and 0.25%) with addition of epinephrine were carried out. Injection of epinephrine alone showed a flow almost as low as at the untreated control sites. Ropivacaine epinephrine injections were followed by a lower skin blood flow compared to saline, but the flow was significantly larger compared to the effect of epinephrine itself at the 20-minute recording.
  
  
  CONCLUSIONS
  The combination of ropivacaine and adrenaline did not accentuate but instead diminished the vasoconstrictive effect of epinephrine.
authors.affiliation: Department of Anaesthesiology, University Hospital, Linköping, Sweden.
authors.forename: I
authors.initials: I
authors.lastname: Cederholm
authors.forename: H
authors.initials: H
authors.lastname: Evers
authors.forename: J B
authors.initials: JB
authors.lastname: Löfström
mesh_terms: D000328:Adult; D000577:Amides / Q000493:pharmacokinetics / Q000494:pharmacology*; D000779:Anesthetics, Local / Q000493:pharmacokinetics / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004347:Drug Interactions; D004837:Epinephrine / Q000494:pharmacology*; D006801:Humans; D007271:Injections, Intradermal; D017078:Laser-Doppler Flowmetry; D008297:Male; D008875:Middle Aged; D012039:Regional Blood Flow / Q000187:drug effects; D000077212:Ropivacaine; D012867:Skin / Q000098:blood supply* / Q000187:drug effects
chemical_list: D000577:Amides; D000779:Anesthetics, Local; D000077212:Ropivacaine; D004837:Epinephrine