Optimizing the safety and practice of ultrasound-guided regional anesthesia: the role of echogenic technology.

aSchool of Medicine and Pharmacology, The University of Western Australia bSir Charles Gairdner Hospital, Perth, Western Australia, Australia.
Current opinion in anaesthesiology 07/2012; 25(5):603-9. DOI: 10.1097/ACO.0b013e328356b835
Source: PubMed

ABSTRACT Significant improvements have been made in the quality of ultrasound imaging, and it is now much easier to see nerves. However, the key to safe ultrasound-guided regional anesthesia is to be able to direct the needle to the target. This relies on good needle visibility. We review the recent advances that have been made in this crucial area.
Echogenic needles can improve shaft and tip visibility independent of experience level, compensate for suboptimal scanning technique, allow steeper insertion angles, reduce technical difficulty, and increase both confidence and satisfaction by anesthesiologists. An echogenic needle encourages holding the probe in one place on the patient, only advancing the needle when it can be seen, hence reducing the likelihood of quality-compromising behaviors. The poor visibility of nonechogenic needles when inserted at steeper angles commonly causes the observer to underestimate the insertion depth of the needle. Significant differences in echogenicity are found when comparing the currently available needles.
Good echogenic needles should increase safety, efficacy, and simplicity, and hopefully further drive the adoption of ultrasound-guided techniques, to the benefit of our patients.

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    ABSTRACT: INTRODUCTION: Needle visualization in ultrasound-guided regional anesthesia can be improved by using needles of echogenic design with higher rate of reflection of ultrasound waves. Imaging solutions such as compound imaging might further improve imaging of both needle and tissue; these effects have not yet been studied. We hypothesized that compound imaging would significantly improve needle visibility, regardless of the insertion angle or needle type used. The effects of compound imaging on needle artifacts and tissue imaging were also investigated. METHODS: A total of 200 video clips of in-plane needle insertions were obtained in embalmed cadavers with a conventional needle and an echogenic needle at 5 different insertion angles, with both conventional B-mode ultrasound imaging and compound imaging technology. Visibility of the needle shaft and needle tip as well as the needle artifact rate were assessed by a blinded investigator on a 4-point ordinal scale. The effects on tissue image quality and speckle artifacts were also assessed. Stepwise linear regression was performed to differentiate effects on needle visibility scores. RESULTS: Imaging of the needle shaft and tip was significantly enhanced when compound imaging technology was used (P < 0.0001). Use of echogenically designed needles or shallow needle insertion angles improved visibility of both shaft and tip (both P < 0.0001). With compound imaging, there are fewer needle artifacts, and tissue imaging quality and speckle artifact rate are significantly improved. CONCLUSIONS: Compound imaging technology enhances needle imaging with both echogenic and conventional needles. Tissue imaging and speckle artifacts are also optimized. Echogenic needle design results in better needle visibility scores in both B-mode and compound imaging.
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May 21, 2014