Article Text

Download PDFPDF
Minimal Blocking Concentrations of Bupivacaine and Procaine in an Exclusively Nociceptive System in Humans
  1. Holger Holthusen, M.D.*,
  2. Peter Lipfert, M.D.* and
  3. Wolfgang Klement, M.D.
  1. *From the Department of Experimental and Clinical Anesthesiology, Heinrich-Heine-University of Düsseldorf
  2. the Department of Anesthesia and Intensive Care Medicine, Jung-Stilling-Krankenhaus, Siegen, Germany.
  1. Reprint requests: Holger Holthusen, M.D., Heinrich-Heine-Universität Düsseldorf, Institut für Klinische Anaesthesiologie, Moorenstraβe 5, D-40225, Düsseldorf, Germany.

Abstract

Background and Objectives: Prior to this investigation, there was no approach to compare both the potency of local anesthetics and their time course of action in a reproducible nociceptive system in humans. We tested whether the vascularly isolated vein segment is appropriate for such an approach.

Methods. In six healthy men, a hand vein segment was vascularly isolated and intraluminally stimulated with electropulses of constant current intensity. The subjects rated pain between threshold and maximally tolerable pain on a visual analogue scale. For determining minimal blocking concentrations (a measure of potency), the vein segment was continuously perfused with Tyrode's solution with increasing concentrations of bupivacaine or procaine for at least 10 minutes each until pain was completely blocked. Subsequently, the respective local anesthetic was rinsed off with Tyrode's solution to determine the time course of recovery.

Results. Both bupivacaine and procaine blocked pain in a concentration-related fashion, the minimal blocking concentrations being 1.6 (0.6-1.9; median and range) mmol/L for bupivacaine and 15.0 (7.5-22.5) mmol/L for procaine. Whereas the onset of block (time of 50% block) did not differ significantly between bupivacaine and procaine [43 s (range, 3-80) vs 53 s (range, 30-115)], local anesthesia lasted significantly longer after application of bupivacaine [278 s (range, 215-325)] than after procaine [183 s (range, 125-225)].

Conclusions. The vascularly isolated vein segment is well suited to compare in vivo the properties of local anesthetics with a minimally invasive approach at a reproducible nociceptive system in humans.

  • bupivacaine
  • procaine
  • pharmacokinetics
  • potency
  • minimal blocking concentration
  • nociceptive afferents.

Statistics from Altmetric.com

Footnotes

  • This study was performed in the Department of Experimental Anesthesiology of the Heinrich-Heine-University, Düsseldorf, and was supported by the Deutsche Forschungsgemeinschaft (Ar 64/8-1).

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.