Discriminative Ability of Dye Injected Into a Meat Model to Determine Accuracy of Ultrasound-Guided Injection.

Introduction: The utility of using meat models for ultrasound-guided regional anesthesia simulation training has been well established. Feedback is considered the most important element of successful simulation-based education, and simulation offers an opportunity for evaluation. The objective of this study was to establish the discriminative ability of dye injected into a meat model to determine whether injectate is properly placed in the perineural (PN) space, thus providing an additional tool for learner feedback and evaluation.

Methods: Meat models containing a beef tendon (simulating a nerve) were injected with dye in one of 3 locations: PN, intraneural, and intramuscular. Blinded assessors then independently interpreted the dye staining on the models, marked the interpreted injection location, ease of interpretation, and whether staining was present on the beef tendon.

Results: Thirty meat models were injected with dye and independently assessed. Determining the location of injection was deemed to be easy or very easy in 72% of the models. Assessors correctly identified PN, intraneural, and intramuscular injections 100%, 95%, and 85% of the time, respectively. Assessor agreement was 87%.

Conclusions: The location of dye injected into a meat model, simulating a peripheral nerve blockade, can be accurately and reliably scored to provide feedback to learners. This technique offers a novel means of providing feedback to trainees and assessing block success in ultrasound-guided regional anesthesia simulation.