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The Second American Society of Regional Anesthesia and Pain Medicine Evidence-Based Medicine Assessment of Ultrasound-Guided Regional Anesthesia: Executive Summary
  1. Joseph M. Neal, MD*,
  2. Richard Brull, MD,
  3. Jean-Louis Horn, MD,
  4. Spencer S. Liu, MD§,
  5. Colin J. L. McCartney, PhD, MBChB,
  6. Anahi Perlas, MD,
  7. Francis V. Salinas, MD* and
  8. Ban Chi-ho Tsui, MD
  1. From the Departments of Anesthesiology, *Virginia Mason Medical Center, Seattle, WA; †Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada; ‡Stanford University, Stanford, CA; §Hospital for Special Surgery, Weill College of Medicine of Cornell University, New York, NY; and ∥University of Ottawa, Ottawa, Ontario; and ¶University of Alberta Hospital, Edmonton, Alberta, Canada
  1. Address correspondence to: Joseph M. Neal, MD, Virginia Mason Medical Center, 1100 Ninth Ave (B2-AN), Seattle, WA 98101 (e-mail: Joseph.Neal{at}


Objectives: In 2009 and again in 2012, the American Society of Regional Anesthesia and Pain Medicine assembled an expert panel to assess the evidence basis for ultrasound guidance as a nerve localization tool for regional anesthesia.

Methods: The 2012 panel reviewed evidence from the first advisory but focused primarily on new information that had emerged since 2009. A new section was added regarding the accuracy and reliability of ultrasound for determining needle-to-nerve proximity. Jadad scores are used to rank study quality. Grades of recommendations consistent with their level of evidence are provided.

Results: The panel offers recommendations based on synthesis and analysis of literature related to (1) the technical capabilities of ultrasound equipment and its operators, (2) comparison of ultrasound to other methods of nerve localization with regard to block characteristics, (3) comparison of block techniques where ultrasound is the sole nerve localization modality, and (4) major complications. Assessment of evidence strength and recommendations are made for upper- and lower-extremity, truncal, neuraxial, and pediatric blocks.

Conclusions: Scientific evidence from the past 5 years has clarified and strengthened our understanding of ultrasound-guided regional anesthesia as a nerve localization tool. High-level evidence supports ultrasound guidance contributing to superior characteristics with selected blocks, although absolute differences with the comparator technique are often relatively small (especially for upper-extremity blocks). The clinical meaningfulness of these differences is likely of variable importance to individual practitioners. The use of ultrasound significantly reduces the risk of local anesthetic systemic toxicity as well as the incidence and intensity of hemidiaphragmatic paresis, but has no significant effect on the incidence of postoperative neurologic symptoms.

What's New in This Update?This evidence-based assessment of ultrasound-guided regional anesthesia reviews findings from our 2010 publication and focuses on new meta-analyses, randomized controlled trials, and large case series published since 2009. New to this exercise is an in-depth analysis of the accuracy and reliability of ultrasound guidance for identifying needle-to-nerve relationships. This version no longer addresses ultrasound for interventional pain medicine procedures, because the growth of that field demands separate consideration. Since our 2010 publication, new information has either supported or strengthened our original conclusions. There is no evidence that ultrasound is inferior to alternative nerve localization methods.

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  • The American Society of Regional Anesthesia and Pain Medicine provided standard travel reimbursement for members of the panel who presented this work in open forum as part of the Society's 38th Annual Regional Anesthesiology and Acute Pain Medicine meeting in Boston, MA, May 3, 2013. No panelist was paid for participation on the panel.

    The authors of this article disclose that over the past 5 years they have had the following relationships with companies, some of which make ultrasound-related equipment: educational honoraria (H), research support (R), or consulting agreements (C): J.M.N., R.B., J.-L.H., C.J.L.M., A.P., F.V.S.: none; S.S.L.: Pacira (C), Mylan Medical (C); B.C.T.: Alberta Heritage Foundation for Medical Research (R), Canadian Institutes of Health Research (R), Canadian Anesthesiologists' Society (R), University Hospital Foundation (R), and Pajunk (C).