Beyond Ultrasound Guidance for Regional Anesthesiology

Abstract

Despite its popularity, ultrasound (US)-guided regional anesthesiology is associated with significant limitations. The latter can be attributed to either the US machine (ie, decreased ability to insonate deep neural structures, as well as the thoracic spine) or the operator. Shortcomings associated with the operator can be explained by errors in perception (ie, ambiguous criteria for needle/catheter tip-to-nerve proximity and subparaneural local anesthetic injection) or interpretation. Perhaps the greatest confusion afflicting US-guided regional anesthesiology originates from an intellectual misconception pertaining to its application. Increasingly, authors are using US to identify interfascial planes where local anesthetic can be injected thereby "discovering" new truncal blocks. Often these novel blocks suffer from a lack of proper randomized, comparative validation.Fortunately, solutions have been proposed to remedy many shortcomings associated with US guidance. The inability of US to reliably insonate deep neural structures can be circumvented with adjunctive neurostimulation. Fluoroscopy and waveform analysis have been proven to increase the success rate of thoracic epidural blocks. For continuous nerve blocks, combined US-neurostimulation may provide an objective end point (ie, an evoked motor response) for neural proximity and subparaneural positioning of the catheter tip. Finally, the solution to the plethora of nonvalidated US-guided blocks is both elegant and simple. New nerve blocks should answer a specific clinical need, and their first descriptions should take the form of an adequately powered, observer-blinded, randomized comparison against the established standard of care or, at the very least, a large case series (eg, a Brief Technical Report).

The Third American Society of Regional Anesthesia and Pain Medicine Practice Advisory on Local Anesthetic Systemic Toxicity

“…45 Within the surgical community, LIA has expanded, particularly in total joint arthroplasty practice. Case reports document LAST occurrences in both truncal block 46 and LIA 47 patients.…”

Ultrasound-Guided Regional Anesthesia and Standard of Care

“…4 In addition, there is also a case to be made that UGRA for peripheral nerve blocks should be strongly encouraged in the high-risk patient, increasing patent safety by decreasing the incidence of local anesthesia systemic toxicity and decreasing the likelihood of intravascular injection. 4,5 We do agree that words matter. Because UGRA is a component of PoCUS, our goal with the PoCUS series is to encourage learning and actively promote the use of PoCUS by the regional anesthesiologist as we believe that PoCUS has emerged as the 21st-century stethoscope.…”

“…This is an expansive statement, given that the practice of regional anesthesia goes beyond the performance of peripheral nerve blocks and includes single and continuous neuraxial techniques, along with the recognition that the use of UGRA alone is associated with pitfalls and limitations. 5 The standard of care for nerve localization and regional anesthesia is not defined by the use of ultrasound. Look no further than one of the supporting articles 6 of the Second American Society of Regional Anesthesia and Pain Medicine (ASRA) Evidence-Based Medicine Assessment of Ultrasound-Guided Regional Anesthesia, 3 which unequivocally states "…the absence of ultrasound (US) machines at all practice locations, the ongoing presence of anesthesiologists extremely experienced and proficient with non-US nerve localization techniques, and with the possible exception of local anesthetic systemic toxicity (LAST), the absence of definitive scientific proof of US's superiority make[s] it impossible to assert that US guidance has become the standard of care for nerve localization.…”

Regionalanästhesie: traditio et innovatio

“…Die Arbeitsgruppe Regionalanästhesie hat sich seit mehreren Jahren der Bewertung der Blockaden von oberer und unterer Extremität und der Nervendetektion gewidmet und die Ergebnisse publiziert [16,17]. Herauszuheben ist die AWMF S1-Leitlinie Handlungsempfehlung zur Nervenlokalisation für periphere Regionalanästhesieverfahren (http://www.awmf.org/leitlinien/detail/ ll/001-026.html), die auch international Beachtung findet [13].…”