Innovations in Airway Education: 3D Printed Neonatal and Pediatric Needle Cricothyrotomy Trainers

Audience Three dimensional printed cricothyrotomy trainers are designed to be used at all levels of training in emergency medicine, both for skill acquisition and to prevent skill atrophy. Introduction Simulation has long provided a means to train providers on rarely performed procedures.1,2 For example, surgical cricothyrotomy has commonly been practiced in a simulated environment almost exclusively via low-fidelity models.3–6 What seems to be lacking in this training is simulation of needle cricothyrotomy for the pediatric population. Needle cricothyrotomy remains the standard of care for temporary airway management in a “can’t intubate, can’t oxygenate” scenario for pediatric patients. In order to address this educational deficiency, we designed a 3D printed pediatric needle cricothyrotomy trainer using evidenced-based cadaveric literature demonstrating neonatal cricothyroid membrane dimensions. These trainers will serve as a simulation tool that will help educate emergency medicine residents to perform a rare, high-stakes procedure within a controlled environment. Educational Objectives By the end of this educational session, participants should be able to: Discuss indications and contraindications for needle cricothyrotomy in the pediatric population. Assemble the equipment needed to complete a needle cricothyrotomy. Describe and perform the steps of neonatal and pediatric needle cricothyrotomy. Discuss post-procedure ventilation options. Educational Methods Trainers were created to enhance needle cricothyrotomy training in this rarely performed, yet critical procedure. It was felt that this procedure was only discussed in concept. There was no hands-on, procedure-based option available to realistically reproduce the procedure in a controlled training environment, and we felt the creation of a task trainer was ideal to address this deficiency. Once the trainers were created, we curated assigned pre-reading using a flipped classroom approach. The idea was to provide learners with multiple resources including textbook chapters, blogs, and podcasts, so that they could choose one or two resources that matched their learning style. We felt this was the best way to ensure learner retention. Additionally, we created a PowerPoint presentation to illustrate the stepwise procedure, required equipment, indications/contraindications, and ventilation aspect of the procedure, which can be reviewed with learners prior to performing the hands-on portion of the skills station. In order to create such a trainer, we worked in conjunction with the OhioHealth Simulation Department to obtain a 3D printer. Adult cricothyrotomy trainers were previously purchased from The Airway App, a company specializing in airway management education. The company also provides a standard template library (.STL) file that contains code for 3D printing cricothyrotomy trainers. Using this code, we made changes to the scale in order to create a smaller model that would resemble neonatal, school-aged, and adolescent patients (25%, 33%, and 50% of the original adult trainer, respectively). These scale models, particularly the neonatal model, were chosen based on the neonatal cadaveric measurements researched by Navasa, et al.7 To prepare the trainer for use, sim skin and sim tape were used to cover and obscure the landmarks. Learners were given the materials previously discussed in preparation of the skills lab. Although all sizes of trainers were used by the learners, particularly attention was paid to the neonatal trainer. Emphasis was placed on the difficulty finding landmarks during this procedure. Instructors were available for the entirety of the skill station in order to answer questions and give direct feedback. Debriefing was performed at the end of the skills session. Research Methods Post-simulation surveys were completed by PGY 1–4 emergency medicine resident physicians assessing pre- and post-simulation procedural comfortability using a 5-point Likert scale. In this survey, 1 represented “not comfortable at all” while 5 represented “completely comfortable.” Two, three, and four showed a gradual increase in comfortability, respectively. Median pre- and post-scores were calculated with interquartile ranges (IQR). A two-tailed Mann-Whitney U test was performed for statistical significance. Realism and future use were also surveyed. Results Thirty-one emergency medicine resident physicians ranging from PGY1 to PGY4 completed the post-simulation survey. Median pre-simulation score was 2 (IQR 1–2.5) and post-simulation score was 4 (IQR 3–4). The two-tailed Mann-Whitney U test showed statistical significance at p<0.01. Ninety-seven percent of participants felt the trainers were realistic and 100% would recommend them for future simulation use. Discussion Novel 3D printed needle cricothyrotomy trainers are a much-needed addition to emergency medicine procedural training. Specifically, we focus on the use of low-cost, high-fidelity trainers for educating emergency medicine resident physicians. By using a pre-templated .STL file, we were able to manipulate sizes and dimensions to create several simulation trainers for simulating needle cricothyrotomy. Our results show that these trainers are valuable to emergency medicine procedural training, increasing resident comfortability. Furthermore, participants feel this is realistic and would recommend this for future simulations. Given the relative ease and low-cost nature of these trainers, in addition to their proven benefit with residents, we hope that others will be able to use similar trainers to help develop needle cricothyrotomy skills at all levels of training. Topics Needle cricothyrotomy, pediatrics, difficult airway, 3D printing, education.

learner retention. Additionally, we created a PowerPoint presentation to illustrate the stepwise procedure, required equipment, indications/contraindications, and ventilation aspect of the procedure, which can be reviewed with learners prior to performing the hands-on portion of the skills station.
In order to create such a trainer, we worked in conjunction with the OhioHealth Simulation Department to obtain a 3D printer. Adult cricothyrotomy trainers were previously purchased from The Airway App, a company specializing in airway management education. The company also provides a standard template library (.STL) file that contains code for 3D printing cricothyrotomy trainers. Using this code, we made changes to the scale in order to create a smaller model that would resemble neonatal, school-aged, and adolescent patients (25%, 33%, and 50% of the original adult trainer, respectively). These scale models, particularly the neonatal model, were chosen based on the neonatal cadaveric measurements researched by Navasa, et al. 7 To prepare the trainer for use, sim skin and sim tape were used to cover and obscure the landmarks. Learners were given the materials previously discussed in preparation of the skills lab. Although all sizes of trainers were used by the learners, particularly attention was paid to the neonatal trainer. Emphasis was placed on the difficulty finding landmarks during this procedure. Instructors were available for the entirety of the skill station in order to answer questions and give direct feedback. Debriefing was performed at the end of the skills session.
Research Methods: Post-simulation surveys were completed by PGY 1-4 emergency medicine resident physicians assessing pre-and post-simulation procedural comfortability using a 5-point Likert scale. In this survey, 1 represented "not comfortable at all" while 5 represented "completely comfortable." Two, three, and four showed a gradual increase in comfortability, respectively. Median pre-and post-scores were calculated with interquartile ranges (IQR). A two-tailed Mann-Whitney U test was performed for statistical significance. Realism and future use were also surveyed.
Results: Thirty-one emergency medicine resident physicians ranging from PGY1 to PGY4 completed the postsimulation survey. Median pre-simulation score was 2 (IQR 1-2.5) and post-simulation score was 4 (IQR 3-4). The two-tailed Mann-Whitney U test showed statistical significance at p<0.01. Ninety-seven percent of participants felt the trainers were realistic and 100% would recommend them for future simulation use.
Discussion: Novel 3D printed needle cricothyrotomy trainers are a much-needed addition to emergency medicine procedural training. Specifically, we focus on the use of low-cost, high-fidelity trainers for educating emergency medicine resident physicians. By using a pre-templated .STL file, we were able to manipulate sizes and dimensions to create several simulation trainers for simulating needle cricothyrotomy. Our results show that these trainers are valuable to emergency medicine procedural training, increasing resident comfortability. Furthermore, participants feel this is realistic and would recommend this for future 3 Section break simulations. Given the relative ease and low-cost nature of these trainers, in addition to their proven benefit with residents, we hope that others will be able to use similar trainers to help develop needle cricothyrotomy skills at all levels of training.

Linked objectives and methods:
Rare procedures such as needle cricothyrotomy require dedicated learning sessions and trainers to develop the knowledge and skill required for procedural success. This procedure training session allows learners to review the situations where this procedure may be indicated, as well as the equipment needed and procedural steps through an introductory PowerPoint and associated pre-simulation reading (objectives 1 and 4). Following the presentation, learners will then describe and perform the procedure on the 3D printed cricothyrotomy trainer, allowing application and tactile feedback through deliberate practice (objectives 2-4).

Recommended pre-reading for instructor:
Note -not all of these are required. We recommend picking 1-2 resources that you prefer from the list below. Once the printer and STL code is obtained, printing time depends on the size of the trainer. In this case, printing time ranged from 25 minutes to several hours depending on the size of the trainer. The basic setup for this simulation takes only a few minutes. This requires taping the printed needle cricothyrotomy trainers to a hard surface and covering them with sim tape, followed by sim skin. A more elaborate setup with accompanying head and body is possible; however, this would require a more involved setup which this session did not entail. We recommend approximately 30 minutes of allotted time for acquisition and skill development. If desired by the instructor, this time can include a brief review of the associated PowerPoint. Debrief time was also minimal, taking only approximately 5 minutes to discuss the difficulty of palpating landmarks and the incredibly small size of the larynges and cricothyroid membranes. Some residents also discussed difficulty with setting up the equipment and connecting all of the individual pieces together.

Recommended Number of Learners per Instructor:
One instructor can give a pre-simulation lecture to any number of participants. Two learners per trainer is optimal, though this is only a recommendation and can be expanded depending on available resources. The number of instructors required to implement the simulation largely depends on the comfortability and training level of the instructor(s). Only one instructor is needed to give the preprocedure PowerPoint, though many may be used to float during the skill lab. During debrief, all learners can come together to discuss their experience with the trainers. In total, we recommend 30 minutes with approximately 5 minutes of pre-procedure PowerPoint review and 5 minutes for debrief.

Objectives:
By the end of this educational session, participants should be able to: 1. Discuss indications and contraindications for needle cricothyrotomy in the pediatric population. 2. Assemble the equipment needed to complete a needle cricothyrotomy. 3. Describe and perform the steps of neonatal and pediatric needle cricothyrotomy. 4. Discuss post-procedure ventilation options.

Implementation Methods:
The session should begin with a single pre-simulation lecture (see associated PowerPoint) lasting approximately 5-10 minutes. This will ensure all learners have a baseline understanding of the needle cricothyrotomy procedure, although all learners should have reviewed the associated material prior to the skills station. Indications and contraindications should be reviewed, and all relevant supplies gathered. Learners are allowed to practice using all sizes of the trainer, with a particular emphasis on the neonatal trainer because this is most difficult procedurally. Trainers can be used indefinitely since they are not damaged during the simulation. Sim skin and foam tape will withstand several attempts on the trainer, but will need to be changed out eventually. This depends largely on the number of attempts each learner is taking. We used a bag-valve for teaching post-procedure ventilation because we did not have access to a jet ventilation system. This option is, however, covered in the associated PowerPoint and accompanying material. If available, we would recommend practicing with the jet ventilation system. Ultimately, learners will be best served by using whatever is available at the location where they practice.

List of items required to replicate this innovation:
1 a. Ideally, these should have a Leur lock in order to connect flushes. Auto-retracting safety needles work but cannot be attached to 10 cc syringes until after the needle is withdrawn. This increases the risk of tracheal posterior wall perforation and esophageal injury. 9. 3 ml syringe 10. 10 cc saline flush Approximate cost of items to create this innovation: Prices range widely for 3D printers, from a couple hundred dollars to thousands. In this case, the Prusa MK3 costs $749 ($999 assembled). 8 Polylactic acid (PLA) printer filament (the wound plastic used for printing) costs approximately $20 per