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Numerous simulation and training methods have been described to improve inexperienced anaesthesiology practitioners' learning of ultrasound-guided techniques, including accurate needle placement [1], types of transducer [2], and needle visualisation [3]. A dynamic ‘traceback’ method has been described and used successfully at our institution for locating the interscalene brachial plexus [4], but this approach has not yet been validated. We compared the dynamic traceback approach with the local sonoanatomy landmark approach (using the cricoid as a landmark) for identifying the brachial plexus in the interscalene groove. We hypothesised that a dynamic, stepwise method such as the traceback approach would yield greater success compared with the local sonoanatomy landmark approach.

Eleven anaesthesiology residents with no prior ultrasound-guided regional anaesthesia experience were randomly assigned, using sealed envelopes containing written instructions, to one of the approaches described in Fig. 1. The residents had five minutes to read the instructions and were given a timed (maximum of 5 min) attempt to obtain a clear ultrasound image of the brachial plexus on a naive volunteer model (BMI 20.6 kg.m−2). After one hour, each resident was given sealed instructions for the other approach, and the procedure was repeated. A portable TITAN ultrasound machine (SonoSite Inc., Bothell, WA, USA) with a C11e, 11 mm footprint, 8–5 MHz probe was used for scanning [5].

image

Figure 1. Comparison of the dynamic traceback approach and local sonoanatomy landmark approach for identification of the brachial plexus in the interscalene groove. In the dynamic traceback approach (A), the probe is positioned on the lateral edge of the clavicle and then moved medially until the pulsating subclavian artery is visible (i). Positioning the artery in the centre of the screen, the brachial plexus can be seen in clusters (i.e. honeycomb shape) lateral, posterior, and often cephalad to the artery (ii). From this point, the brachial plexus is traced upwards to the interscalene groove: the probe is moved upwards while maintaining the angle of the probe (iii). The nerve structures can be seen in a transverse view as multiple round or oval dark areas between the anterior (ASM) and median scalene (MAM) muscles (iv). In the local sonoanatomy landmark approach (B), the probe is moved from medial to lateral at the larynx (i), and the carotid artery and internal jugular vein (IJ) are identified (ii). The probe is then moved sideways to the lateral border of the sternocleidomastoid muscle (SCM) with a slight caudal movement of the tip of the probe (iii). The nerve structures can be seen in a transverse view as multiple round or oval dark areas between the anterior and median scalene muscles (iv).

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On the first attempt, 1/6 (16.7%) residents using the local sonoanatomy landmark approach successfully obtained a clear image of the brachial plexus at the interscalene level, compared with 5/5 of the residents (100%) using the traceback method. On the second attempt, 2/5 (40%) of those using the local sonoanatomy landmark method were successful, compared with 6/6 (100%) residents using the traceback approach.

Compared with the local sonoanatomy landmark method, residents using the traceback method were able to obtain acceptable images of the brachial plexus at the interscalene level with a high degree of success. The traceback approach may be a useful training aid for practitioners who have little or no experience in ultrasound-guided regional anaesthesia.

Acknowledgements

  1. Top of page
  2. Acknowledgements
  3. References

The author wishes to thank Dr Brendan Finucane, Dr Ravi Bhargava, and Jennifer Pillay for assistance with the study and D. Gareth Corry for assistance with manuscript preparation.

References

  1. Top of page
  2. Acknowledgements
  3. References
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    Davies T, Townsley P, Jlala H, et al. Novice performance of ultrasound-guided needle advancement: standard 38-mm transducer vs 25-mm hockey stick transducer. Anaesthesia 2012; 67: 85561.
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    Gupta RK, Lane J, Allen B, Shi Y, Schildcrout JS. Improving needle visualization by novice residents during an in-plane ultrasound nerve block simulation using an in-plane multiangle needle guide. Pain Medicine 2013 Jun 11; doi 10.1111/pme.12160.
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    Tsui BCH. Atlas of Ultrasound and Nerve Stimulation-Guided Regional Anesthesia. New York, Springer, 2007. p. 68.
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    Tsui BC, Doyle K, Chu K, Pillay J, Dillane D. Case series: ultrasound-guided supraclavicular block using a curvilinear probe in 104 day-case hand surgery patients. Canadian Journal of Anesthesia 2009; 56: 4651.