The cantaloupe study: A novel method for teaching epidural placement
Abstract Number: F-47
Abstract Type: Original Research
Epidural placement is an important skill for anesthesiologists, yet is a difficult procedure to teach trainees. Loss of resistance (LOR) to air or saline is a commonly used method for finding the epidural space, and is a subjective skill that can be difficult to demonstrate. We investigate the use of a novel model for teaching “feel” for LOR to anesthesia trainees using a cantaloupe as a simulator. Cantaloupes have a unique anatomy, with a thick exocarp (rind), dense and edible mesocarp interior, and a central endocarp containing seeds. The average distance from the exocarp to the endocarp is 5cm. Upon inserting an epidural needle into a cantaloupe, the mesocarp provides an excellent model for needle engagement in the midline ligaments of the back. When the endocarp is reached, the operator experiences a LOR that is similar to that encountered in the epidural space.
Eligible subjects included rotating anesthesiology resident physicians and student nurse anesthetists on their initial obstetric anesthesia rotation at a major training hospital. Trainees who had already placed 20 or more epidurals were excluded. Study subjects were randomized into an intervention and control groups and were given an orientation on epidural placement. The interventional group was offered unlimited practice with the cantaloupe model; the control group was not allowed to use the cantaloupe model. 58 trainees were enrolled in the study from January 2014 through October 2015; 28 were randomized to the control group and 30 were randomized to the cantaloupe intervention group. The majority (n=55, 94.8%) had placed fewer than 5 epidurals at the time of their initial rotation; none had placed more than 10. Across the first 3 epidurals placed by each of the 58 participants, a total of 9 unintentional dural punctures (wet taps) occurred with no significant difference in wet taps between the two groups (p=0.235).
All subjects were asked to practice on the cantaloupe and rate the effectiveness of the cantaloupe as a training tool for epidural placement. 28 of the 30 participants in the intervention group rated the cantaloupe model as helpful in teaching LOR technique for epidural placement. More trainees rated the cantaloupe model as effective for LOR to air (88.2%) than for LOR to saline (74.5%). No significant difference was found in the overall number of wet taps between the control and intervention groups (p=0.98).
The cantaloupe model is an economical and easy to implement method for teaching trainees the LOR technique for epidural placement. The model was rated as helpful by a large majority of participants, and was a useful simulation of LOR to both air and saline. Using models during the early part of learning a new skill can be an effective teaching method, and cultivating the ability to sense a sudden change in pressure can speed up the learning process and potentially decrease the risk of unintentional dural puncture.