Comparison of the development of performance skills in ultrasound-guided regional anesthesia simulations with different phantom models

Abstract

Background: Ultrasound-guided regional anesthesia (UGRA) skills are traditionally obtained by supervised performance on patients, but practice on phantom models improves success. Currently available models are expensive or use perishable products, for example, olive-in-chicken breasts (OCB). We constructed 2 inexpensive phantom (transparent and opaque) models with readily available nonperishable products and compared the process of learning UGRA skills by novice practitioners on these models with the OCB model.

Methods: Three experts first established criteria for a satisfactory completion of the simulated UGRA task in the 3 models. Thirty-six novice trainees (<20 previous UGRA experience) were randomly assigned to perform a UGRA task on 1 of 3 models-the transparent, opaque, and OCB models, where the hyperechoic target was identified, a needle was advanced to it under ultrasound guidance, fluid was injected, and images were saved. We recorded the errors during task completion, number of attempts and needle passes, and the time for target identification and needle placement until the predetermined benchmark of 3 consecutive successful UGRA simulations was accomplished.

Results: The number of errors, needle passes, and time for task completion per attempt progressively decreased in all 3 groups. However, failure to identify the target and to visualize the needle on the ultrasound image occurred more frequently with the OCB model. The time to complete simulator training was shortest with the transparent model, owing to shorter target identification times. However, trainees were less likely to agree strongly that this model was realistic for teaching UGRA skills.

Conclusions: Training on inexpensive synthetic simulation models with no perishable products permits learning of UGRA skills by novices. The OCB model has disadvantages of containing potentially infective material, requires refrigeration, cannot be used after multiple needle punctures, and is associated with more failures during simulated UGRA. Direct visualization of the target in the transparent model allows the trainee to focus on needle insertion skills, but the opaque model may be more realistic for learning target identification skills required when UGRA is performed on real patients in the operating room.