Development of an Inexpensive, Reusable, Novel Emergency Department Thoracotomy Partial Task Trainer
Authors
Mark J. Bullard1, MD, MS-HPEd, Christie L. Bullard2, RN, John D. Ehlers III, BA2, Kyle W. Cunningham3, MD, MPH, Jeffrey W. Bullard, MD
1Atrium Health, Carolinas Simulation Center, Carolinas Medical Center, Department of Emergency Medicine, Charlotte, North Carolina
2Atrium Health, Carolinas Simulation on Center, Charlotte, North Carolina
3Atrium Health, Carolinas Simulation Center, Carolinas Medical Center, Department of Surgery, Charlotte, North Carolina
Conflict of Interest Statement
Authors have no conflicts of interest.
Authors would like to acknowledge: Carolinas Simulation Center, Atrium Health
Corresponding Author
Mark J. Bullard, MD, MS-HPEd, Wake Forest School of Medicine, Department of Emergency Medicine, Carolinas Medical Center, Carolinas Simulation Center, Atrium Health
Email: Mark.bullard@atriumhealth.org
Brief Description
We designed and built a reusable, durable, low-cost emergency department thoracotomy (EDT) partial task trainer with functional and structural fidelity for repetitive practice of EDT. Learning objectives focused on the step-by-step cognitive process and experience of emergent thoracotomy. Trainer description (Figure 1), components and total cost (Table 1) are outlined within the manuscript.
Background
EDT requires immediate, decided action by emergency providers. Survival rates vary depending on mechanism and literature, however victims of penetrating thoracic trauma requiring EDT have shown a survival rate of 9-38% if used in appropriate patients (Hunt et al., 2006). While indications and timing of EDT continue to be refined and debated, emergent thoracotomy remains a procedure required of emergency physicians, yet still represents a low frequency, high-risk procedure in even the highest volume trauma centers. Further, it has been demonstrated that patients undergoing EDT at higher volume trauma centers have significantly greater odds of survival (Dumas et al, 2018). Lack of educational exposure in EDT is due to many facets: limited indication, invasiveness of EDT, ethical debate surrounding post-mortem procedures, variation of regional and hospital policy and limited, albeit expensive commercial thoracotomy task trainers. Frequency of training and repetition improves outcomes. Unfortunately, some emergency medicine (EM) residents graduate training programs without performing or observing this unique procedure, despite EDT being a required skill for independent EM practitioners. Unfortunately, there are very few commercial thoracotomy models on the market, and these task trainers are very expensive. Further, recognizing that skills decay can affect learning retention, it is important for learners to have reusable, low-cost mechanisms for repetitive practice.
Objective
Addressing the above challenges, we aimed to design and build an inexpensive, reusable thoracotomy task trainer with high functional fidelity. While structural fidelity (physical resemblance) certainly influences suspension of disbelief for learners, we emphasized our design to focus on specific learning objectives and the “functional correspondence between the simulator and the applied context” (Hamstra et al., 2014). For our learners, we determined it most important that they become facile with using the necessary equipment for the step-by-step process involved in an EDT. Our designed trainer functionality was based on specific learning objectives which included: 1) Incising integumen at the 5th intercostal space to gain entry into the thorax, 2) Proper positioning and use of rib spreaders to maximize the surgical field, 3) Using long pick-ups and curved Mayo scissors to incise the pericardium while avoiding the phrenic nerve, 4) Delivering the heart from a clotted pericardium, and 5) Cross-clamping the descending aorta.
EDT is not a technically complex procedure; arguably, EDT requires few technical steps relative to other procedures, however, the procedure does require step-by-step cognitive processes and experience to act quickly. EDT requires a clinician to decidedly use appropriate equipment to gain access into the thorax and pericardial space, deliver the heart from the pericardium and subsequently cross-clamp the descending aorta. The left anterolateral thoracotomy is the most common approach used in the emergency department because this approach addresses the major causes of acute deterioration due to penetrating trauma: pericardial tamponade, tension pneumothorax, and acute hemorrhage from the left hemi-thorax. A left anterolateral thoracotomy approach also enables the cross-clamping of the descending aorta with resultant maintenance of perfusion to vital organs. Therefore, we primarily aimed to design a reusable EDT trainer to appropriately entertain these vital steps for frequent learner repetition while limiting expense.
Methods
We designed a reusable, durable left anterolateral thoracotomy partial task trainer with the outlined materials (Table 1). A recycled airway manikin was attached to the thoracotomy task trainer to add to the overall structural fidelity (Figure 4), however, this was not felt a necessity for the desired learning objectives and functionality of the trainer. Skin was made at our simulation center using Smooth-On (Smooth-on Inc, Macungie, PA). The pericardium was created by taping a string in a sagittal plane on a gallon Ziplock (S.C. Johnson & Son, Racine, WI) bag. We also filled the Ziplock bag with Red Hots (Ferrara Candy Company, Chicago, IL) candy to represent clotted pericardial blood causing tamponade physiology. This candy was chosen due to its red color, ability to be reused, and to also avoid any gelatinous or liquid material that would require trainer clean-up after relief of tamponade physiology. The heart (Figure 6) was created by our simulation center using Ecoflex silicone rubber (Smooth-on In, Macungie, PA) poured into a cardiac mold and placed in the gallon Ziplock bag. The heart was not attached to simulated vessels, but rather placed loosely within the pericardium for the representative step and experience of delivering the heart from the pericardium during the procedure.
Table 1: Materials for EDT partial task trainer (cost without airway head/artificial skin: $225)
Construction of Task Trainer
The items used in the construction of the EDT trainer are available at local hardware stores. The only exception: the sleeve bearing/bushing for two of the ribs, which can be ordered online.
1. The base of the trainer was cut to size from 3/4" thick plywood (23” x 20”).
2. A dado was cut in the base 2" from each end that was 3/4" wide and 3/8" deep.
3. The semicircular end pieces were cut with a 10" radius (Figure 1).
4. 1⁄2" wide holes were drilled 3/8" deep in the semicircular end pieces for the four aluminum rods.
5. 12 ribs were cut from a template traced on ¾” plywood (Figure 2).
6. All pieces were rounded over with a ¼” round-over bit and carefully sanded.
7. Ribs #3 and #4 on the left hemithorax required larger holes to account for a sleeve bearing/bushing permitting easier sliding. All the other rib holes were 1⁄2 inch in diameter (Figure 3).
8. A 1-Gallon Ziplock bag simulated the pericardium and was held in place by four brass rods (1/8” in diameter) with alligator clips on each end (Figure 5).
9. Except for the glued surfaces, the trainer bottom and sides were varnished prior to assembly.
10. Ribs were spray-painted white with an appropriate size temporary dowel in each hole to prevent paint getting into the surface that slides on the aluminum rods.
11. Upright semicircular end pieces were installed into the previously dados. One end piece was glued and screwed into place followed by four aluminum rods.
12. Each rib was placed on the aluminum rods and separated each with ½” (internal diameter) compression springs.
13. The other end was installed with glue and screws.
14. A 2" wide brace was attached off-center on each outside end to prevent “racking” of the trainer.
15. The brass rods with alligator clips on the tips were inserted into the holes.
16. An airway manikin head was available and was attached to the cephalad portion of the trainer.
17. Vena cava, aorta, and esophagus were inserted using out of different colored PEX tubing in appropriate anatomical position.
Figure 1: Semicircular end pieces for task trainer.
Figure 2: Rib template.
Figure 3: Task Trainer without 1-Gallon Ziplock pericardium, alligator clips in place. Ribs #3 and #4 with bushings.
Figure 4: Task Trainer without surgical towel prep and skin
Figure 5: Task trainer prepped and draped with latex heart and Red Hots candy within pericardium.
Figure 6: Silicone heart
Figure 7: EDT procedure
Supplemental Digital Content 1: (https://youtu.be/Pn1H5KcS2Vw)
Discussion
This model represents a novel, inexpensive, durable, reusable EDT task trainer with high functional fidelity and quality physical resemblance. This EDT trainer focuses on specific learning objectives based on the functional task of the step-by-step process of performing an EDT (Supplemental Digital Content 1). When used within a hybrid human-patient manikin simulation context, this EDT trainer further adds to the cognitive experience of making the decision to proceed with EDT, and allows learners to: intubate, incise the integumen to gain access into the thorax, use surgical rib spreaders, perform a pericardiotomy while avoiding the phrenic nerve, deliver the heart from the pericardium, and cross-clamp the aorta using a vascular clamp. Similar task trainers have demonstrated improved learner confidence (Yates et al., 2018, Bengiamin et al., 2019, O'Connell et al., 2020), improved time to thoracotomy incision and over-all procedural time (Park et al., 2020, Hamilton et al., 2015). The authors: a retired physician (JB) and two experts in performing EDT (MB and KC), agreed that the EDT trainer allowed learners to meet the designed learning objectives and thus had high functional fidelity. Additionally, it was felt by these experts that the trainer had quality physical resemblance. Inclusion of lungs may have increased the trainer’s physical resemblance, however, incising of the inferior pulmonary ligament was not a designed learning objective as this step is not necessary in EDT and risks injury to the inferior pulmonary vein (Cothren & Moore, 2006). Thus, the exclusion of lungs did not affect the functional fidelity of the trainer and ultimately saved on cost.
Current commercial thoracotomy trainers are both limited in number and are costly, with prices ranging from 10 to 20 thousand dollars (Yates et al., 2018, Bengiamin et al., 2019). This cost would be prohibitive for many simulation programs. Additionally, commercial thoracotomy trainers often place emphasis on high physical resemblance or structural fidelity. Unfortunately, it is an often-misheld belief that the more physically accurate a trainer, the higher quality. High physical resemblance, however, exponentially adds cost to trainers. The overemphasis on structural fidelity can steer away from the educational effectiveness of a simulator (Hamstra et al, 2014). Furthermore, when design emphasis is shifted from the physical resemblance of a trainer to the functional aspects of a trainer when used within a more global simulation context, learning is not affected (Hamstra et al, 2014). Thus, when viewed in this construct, the physical resemblance of a trainer can be greatly reduced and consequently, non-commercial trainers can be easily created without exponential costs and without affecting learning (Hamstra et al, 2014).
EDT is not a technically complex procedure. Arguably, the most challenging component of EDT is making the cognitive leap to proceed. EDT is time sensitive; needs quick action to incise, rib spread, release pericardial tension, deliver the heart and cross-clamp the aorta. None of these steps are difficult, but knowing the step-by-step process and tools needed is imperative for haste. Simulation training for resuscitative thoracotomy has demonstrated decreased time to intervention (O'Connell et al., 2020, Park et al., 2020). Decreased time saves lives.
Skill and knowledge can quickly decay after simulation-based education (Ellis et al. 2015, Braun et al., 2016, Aqel & Ahmad, 2014). Thus, it is imperative that learners have repetitive practice in cognition and physical tasks such as EDT to attain and maintain skills. With this in mind, non-commercial skin, pericardium, phrenic nerve and coagulated blood were designed for quick and inexpensive replacement allowing the model to be used again, within minutes, at a fraction of the cost of commercial trainers. Logistical considerations such as expense and time needed for repetitive practice must be considered for iterative training. Afterall, centers that perform more EDTs have better patient outcomes (Dumas et al., 2018).
EDT remains a critical skill for EM residents to learn prior to completing residency. The ability to inexpensively create opportunities for repetitive practice with well-designed functional fidelity further argues the importance of prioritizing functional requirements of a non-commercial trainer over the often cost-prohibitive high physical resemblance of a commercial trainer. This model adds to a small but growing group of non-commercial EDT task trainers for experiential instruction on a unique, high-risk, low frequency procedure (Cothren & Moore, 2006, Yates et al., 2018, Bengiamin et al., 2019) (Figure 7).
SDC Legend
SDC 1. Video of EDT trainer in use by EDT content expert. (https://youtu.be/Pn1H5KcS2Vw)
References
Aqel, A. A., & Ahmad, M. M. (2014). High-fidelity simulation effects on CPR knowledge, skills, acquisition, and retention in nursing students. Worldviews on evidence-based nursing, 11(6), 394–400. https://doi.org/10.1111/wvn.12063.
Bengiamin, D. I., Toomasian, C., Smith, D. D., & Young, T. P. (2019). Emergency Department Thoracotomy: A Cost-Effective Model for Simulation Training. The Journal of emergency medicine, 57(3), 375–379. https://doi.org/10.1016/j.jemermed.2019.06.022
Braun, L., Sawyer, T., Smith, K., Hsu, A., Behrens, M., Chan, D., Hutchinson, J., Lu, D., Singh, R., Reyes, J., & Lopreiato, J. (2015). Retention of pediatric resuscitation performance after a simulation-based mastery learning session: a multicenter randomized trial. Pediatric critical care medicine : a journal of the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies, 16(2), 131–138.
Cothren, C. C., & Moore, E. E. (2006). Emergency department thoracotomy for the critically injured patient: Objectives, indications, and outcomes. World journal of emergency surgery : WJES, 1, 4. https://doi.org/10.1186/1749-7922-1-4
Dumas, R. P., Seamon, M. J., Smith, B. P., Yang, W., Cannon, J. W., Schwab, C. W., Reilly, P. M., & Holena, D. N. (2018). The epidemiology of emergency department thoracotomy in a statewide trauma system: Does center volume matter?. The journal of trauma and acute care surgery, 85(2), 311–317. https://doi.org/10.1097/TA.0000000000001937
Ellis, S. M., Varley, M., Howell, S., Trochsler, M., Maddern, G., Hewett, P., Runge, T., & Mees, S. T. (2016). Acquisition and retention of laparoscopic skills is different comparing conventional laparoscopic and single-incision laparoscopic surgery: a single-centre, prospective randomized study. Surgical endoscopy, 30(8), 3386–3390. https://doi.org/10.1007/s00464-015-4619-6
Gallagher, A. G., Jordan-Black, J. A., & O'Sullivan, G. C. (2012). Prospective, randomized assessment of the acquisition, maintenance, and loss of laparoscopic skills. Annals of surgery, 256(2), 387–393. https://doi.org/10.1097/SLA.0b013e318251f3d2
Hamilton, A. J., Prescher, H., Biffar, D. E., & Poston, R. S. (2015). Simulation trainer for practicing emergent open thoracotomy procedures. The Journal of surgical research, 197(1), 78–84. https://doi.org/10.1016/j.jss.2015.04.037
Hamstra, S. J., Brydges, R., Hatala, R., Zendejas, B., & Cook, D. A. (2014). Reconsidering fidelity in simulation-based training. Academic medicine : journal of the Association of American Medical Colleges, 89(3), 387–392. https://doi.org/10.1097/ACM.0000000000000130
Hunt, P. A., Greaves, I., & Owens, W. A. (2006). Emergency thoracotomy in thoracic trauma-a review. Injury, 37(1), 1–19. https://doi.org/10.1016/j.injury.2005.02.014
O'Connell, A., Zhang, X. C., Crossman, M., Misuro, S., & Stobart-Gallagher, M. (2020). Making the Cut: Implementing a Low Cost, Low Fidelity Simulation Model for Teaching Emergency Thoracotomy Procedure. Cureus, 12(5), e8088. https://doi.org/10.7759/cureus.8088
Park, C., Grant, J., Dumas, R. P., Dultz, L., Shoultz, T. H., Scott, D. J., Luk, S., Abdelfattah, K. R., & Cripps, M. W. (2020). Does simulation work? Monthly trauma simulation and procedural training are associated with decreased time to intervention. The journal of trauma and acute care surgery, 88(2), 242–248. https://doi.org/10.1097/TA.0000000000002561
Yates, E., Chirurgi, R., Adamakos, F., Habal, R., Jaiswal, R., Kalantari, H., & Hassen, G. W. (2018). Development and Utilization of 3D Printed Material for Thoracotomy Simulation. Emergency medicine international, 2018, 9712647. https://doi.org/10.1155/2018/9712647