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Electromyographic assessment of ulnar nerve motor block induced by lidocaine.

Publication ,  Journal Article
Atanassoff, PG; Kelly, DJ; Ayoub, CM; Brull, SJ
Published in: J Clin Anesth
December 1998

STUDY OBJECTIVE: To determine the differences in the onset time and duration of motor block produced by lidocaine 1% and lidocaine 2% via a quantitative and objective method, the measurement of compound muscle action potentials (CMAPs). STUDY DESIGN: Prospective study. SETTING: Main operating rooms of a university hospital. PATIENTS: 20 consecutive patients undergoing surgery not requiring intraoperative muscle relaxation. INTERVENTIONS: General anesthesia with unilateral ulnar nerve block was administered. In patients' nondominant (experimental) arms, an insulated block needle was placed adjacent to the ulnar nerve at the wrist while continuous nerve stimulation was delivered to ensure its proper placement. Through this needle, lidocaine 1% or lidocaine 2% was injected. The dominant (control) arm received no injection. MEASUREMENTS AND MAIN RESULTS: Monitoring of ulnar nerve-evoked CMAPs was performed simultaneously on both arms. Ulnar nerve function was assessed at baseline and then at 10-second intervals by automatically measuring the amplitude of the evoked CMAPs on a two-channel electromyogram. The mean (+/- SEM) baseline CMAP amplitude prior to injection of lidocaine 1% was 3.10 +/- 0.87 mV and 3.06 +/- 0.89 mV for the experimental and control ulnar nerves, respectively (p = NS); for lidocaine 2%, baseline CMAP amplitude was 3.58 +/- 1.39 mV and 3.70 +/- 1.46 mV, respectively (p = NS). Over the course of the study, the control CMAP amplitude varied by < 12%. At the experimental ulnar nerve, 90% CMAP decrease after injection of lidocaine 1% and lidocaine 2% occurred 7.5 +/- 2 minutes and 5 +/- 1.5 minutes, respectively (p = NS), whereas maximal blockade was achieved after 15 +/- 3 minutes and 11 +/- 5 minutes, respectively (p = NS). Recovery of CMAP to 90% of baseline occurred 184 +/- 31 minutes after injection of lidocaine 1% and 248 +/- 30 minutes following lidocaine 2% (p = NS). CONCLUSION: The present study describes a technique that can be used in vivo to objectively measure the speed of onset and duration of local anesthetic-induced motor blockade. Although statistically not different, lidocaine 2% demonstrated a faster onset and longer duration of ulnar nerve motor block than lidocaine 1%.

Duke Scholars

Published In

J Clin Anesth

DOI

ISSN

0952-8180

Publication Date

December 1998

Volume

10

Issue

8

Start / End Page

641 / 645

Location

United States

Related Subject Headings

  • Ulnar Nerve
  • Time Factors
  • Prospective Studies
  • Nerve Block
  • Motor Neurons
  • Middle Aged
  • Male
  • Lidocaine
  • Humans
  • Female
 

Citation

APA
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ICMJE
MLA
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Atanassoff, P. G., Kelly, D. J., Ayoub, C. M., & Brull, S. J. (1998). Electromyographic assessment of ulnar nerve motor block induced by lidocaine. J Clin Anesth, 10(8), 641–645. https://doi.org/10.1016/s0952-8180(98)00106-8
Atanassoff, P. G., D. J. Kelly, C. M. Ayoub, and S. J. Brull. “Electromyographic assessment of ulnar nerve motor block induced by lidocaine.J Clin Anesth 10, no. 8 (December 1998): 641–45. https://doi.org/10.1016/s0952-8180(98)00106-8.
Atanassoff PG, Kelly DJ, Ayoub CM, Brull SJ. Electromyographic assessment of ulnar nerve motor block induced by lidocaine. J Clin Anesth. 1998 Dec;10(8):641–5.
Atanassoff, P. G., et al. “Electromyographic assessment of ulnar nerve motor block induced by lidocaine.J Clin Anesth, vol. 10, no. 8, Dec. 1998, pp. 641–45. Pubmed, doi:10.1016/s0952-8180(98)00106-8.
Atanassoff PG, Kelly DJ, Ayoub CM, Brull SJ. Electromyographic assessment of ulnar nerve motor block induced by lidocaine. J Clin Anesth. 1998 Dec;10(8):641–645.
Journal cover image

Published In

J Clin Anesth

DOI

ISSN

0952-8180

Publication Date

December 1998

Volume

10

Issue

8

Start / End Page

641 / 645

Location

United States

Related Subject Headings

  • Ulnar Nerve
  • Time Factors
  • Prospective Studies
  • Nerve Block
  • Motor Neurons
  • Middle Aged
  • Male
  • Lidocaine
  • Humans
  • Female