The role of ischaemia in the analgesia which follows Bier's block technique

Roberto Casale, Chris Glynn, Michelangelo Buonocore

Research output: Contribution to journalArticle

Abstract

The effect of 30-min tourniquet ischaemia (Bier's block) on the antidromic homolateral left median nerve sensory potential (SP) and on the bilateral sympathetic skin response (SSR) was studied in 6 healthy volunteers. The SSR was provoked both acoustically and by electrical stimulation of the median nerve; the latter stimulus was also used to provoke the SP. After 28 min of tourniquet ischaemia, the electrical stimulus failed to provoke the SP and bilateral SSR, indicating blockade of the afferent limb of the reflex. The acoustic SSR was unaffected by ischaemia, and thus the efferent limb of the SSR was not blocked, indicating that ischaemia does not affect the post-ganglionic efferent C fibres. These findings confirm that 30 min of ischaemia blocks Aβ afferent fibres but does not block efferent C fibres. Thus the analgesia following Bier's block alone, in some patients with sympathetically maintained pain, most likely results from the ischaemic blockade of sensory Aβ fibres, confirmed both acoustically and by electrical stimulation of the median nerve.

Original languageEnglish
Pages (from-to)169-175
Number of pages7
JournalPain
Volume50
Issue number2
DOIs
Publication statusPublished - 1992

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Keywords

  • Bier's block
  • Ischaemia
  • Sensory potential
  • Sympathetic skin response
  • Sympathetically maintained pain

ASJC Scopus subject areas

  • Clinical Neurology
  • Psychiatry and Mental health
  • Neuroscience(all)
  • Neurology
  • Pharmacology
  • Clinical Psychology

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