Evaluation of a Low-Cost, Innovative Radial Artery Catheterization Trainer
Authors
Jason E. Konzelmann, BS, M.Ed., NR-P, CHSOS, CHSE1, Jonathan Titus, AS2
1University of Central Florida College of Medicine, Orlando, Florida
2DeSales University, Center Valley, Pennsylvania
Conflict of Interest Statement
The authors report no financial interest in the material presented here.
Corresponding Author
Jason Konzelmann, University of Central Florida – College of Medicine, Clinical Skills and Simulation Center, Orlando, Florida
(Email: jason.konzelmann@ucf.edu)
Abstract
Radial artery catheterization training is needed for acute care. It is used the world over in ICUs and other critical care units. They are placed in the radial, brachial, or femoral arteries. The commercially available trainers are expensive (ranging from $US700 to more than $US3,000), are more suited for arterial blood gas collection practice, and lack suitable anatomical accuracy. The trainer described here is cost effective, places the radial artery pulsations in an anatomically correct location, and accommodates a guide wire better using a long straight “artery,” addressing concerns faculty identified in prior years with other commercially available trainers. Initial usage of the prototype was with faculty and learners in a skills training for the Acute Care Nurse Practitioner course.
Methods
An existing, commercially available peripheral intravenous line task trainer was repurposed for this project. The latex veins were removed and replaced with a single latex tube secured in the anatomical location of the radial artery. A palpable pulse was achieved with the use of a syringe with a luer lock adapter.
Results
Learners completed a survey evaluating the anatomic and physiological fidelity after using the simulator. The learners highly recommended continued use of this model for training (mean = 4.6) learners in the procedure and identified radial artery location, ability to insert the guidewire, ability to insert the catheter, and overall anatomic accuracy as strengths of the model. Learner comfort notably increased from uncomfortable (mean = 1.8) to comfortable (mean = 4.2) after practicing radial artery catheterization on this model.
Conclusion
This novel, low-cost, radial artery catheterization task trainer is an effective task trainer for practicing the full procedure. The accuracy of anatomic location of the radial artery and the feel of the pulse even after multiple catheterizations makes this trainer superior to currently available commercial task trainers marketed for this purpose.
Introduction
Arterial lines are used for a variety of tests in ICU, PICU, NICU, CCU, and acute care settings. This lifesaving procedure is often employed when monitoring blood pressure (BP) more precisely than non-invasive BP monitoring (Pierre, et. al., 2023, Tegtmeyer, et.al., 2006, and Parandis, et.al., 2022) is needed, or frequent arterial blood draws are required (Tegtmeyer, et.al., 2006). Though complications are comparatively rare, successful first try completion can be as low as 50% (Prandis, et.al., 2022).
Wang, et al, identified arterial catheter insertion as a skill essential to the practice of the emergency physician (Wang, et al, 2008) at the EM Consensus Conference on the Science of Simulation in Healthcare. Nestel, et al, concluded that simulation results in increased knowledge and skill while the learner found simulation as a teaching tool to be highly satisfactory (Nestel, et al, 2011). Procedural skills training using training tools with the appropriate fidelity in comparison to real patients combined with the necessary anatomic and physiologic features to complete the skill being taught (Lefor, et al, 2020) allows for practice without risk to real patients, especially for skills requiring technical precision and higher patient risk (Wang, et al, 2008, Sagalowski, et al, 2016, and Sing & Restivo, 2023). The safe environment fostered in the simulation setting allows for repetition, reflective practice, nurturing feedback, and allows for skill acquisition at the pace of the individual learner to proceed to higher levels of competency, proficiency and mastery (Sagalowski, et al, 2016, and Sing & Restivo, 2023).
However, commercially available models for radial artery catheterization are costly, have debatable anatomic accuracy, and often require frequent changes to consumable parts to maintain the needed level of tactile fidelity. Commercially available trainers are also designed with short areas for catheter insertion leaving little distance or smooth pathway for the insertion of a guidewire, hindering realism and adding to the cost of practicing the procedure. The device designed and described here is less costly, repurposes materials likely already present in a simulation center, is easy to maintain, and virtually eliminates the pitfalls associated with the commercially available radial artery simulators. This design has also withstood dozens of punctures during the initial trial with comparatively little leakage and no continuous bleeding after catheter withdrawal.
Materials and Methods
An IV training arm that is no longer supported by the original manufacturer is used as the base of the trainer. However, obsolescence to recreate this model is not a requirement because this can be replicated on any IV training arm without compromising its intended purpose; the IV insertion points do not overlap with the location for radial artery catheterization and placement of the radial artery tubing as described later can be accomplished without interruption to the trainer’s venous flow. Supplies and costs are listed in Table 1.
Process
1. Remove the skin from the IV arm trainer. We removed the existing venous tubing to work with a fresh mandrel. Ultimately, this is not necessary as the process from this point on can be applied over the existing venous tubing depending on center needs when making the radial artery catheterization trainer. See Figure 1.
2. Measure the latex tubing. This should be long enough (approximately 3-4 feet in length) to have approximately 6 inches of tubing extend beyond the top of the skin once reapplied and run continuously down the anterior surface of the forearm, wrap around the finger area and back to the “shoulder” of the simulator. Tack into place with tape.
3. Align the tubing in the anatomic location of the radial artery – approximately at the base of the thumb running toward the antecubital fossa. The return track of the tubing should be placed in the anatomic location of the ulnar artery – anterior surface of the arm approximately at the base of the pinky. See Figure 2.
4. Take 2x2 gauze pads and fold in half. Align them along both sides of the radial artery with the folded side toward the artery. These help prevent the artery from collapsing once the skin is replaced, allow for the feeling of the soft tissue that is present in a real arm to enhance the feeling, and help absorb internal leakage with successive cannulation attempts. Gauze pads should be approximately the same height of the tubing or fractionally higher. Repeat for the ulnar artery location. See Figure 2.
5. Secure runs of tubing in place in a straight line path with the tape. Use caution placing tape over the top of the palpable area of the radial and ulnar arteries; too much tape will reduce the pulsatile feeling later. Other areas proximal and distal to the radial artery palpation area can be secured more firmly, but not so as to pinch the tubing (use more gauze to ballast these areas if needed to prevent pinching). See Figure 2.
6. Insert the luer lock to hose barb adapter to the end of the tubing that travels first to the radial artery location. A zip tie may be used to secure the hose barb to the tubing; however, we did not find this to be needed.
7. Fill a 60cc luer lock syringe with sterile or distilled water that has been colored red with either food coloring or sufficient simulated blood. See Figure 3.
8. Evacuate remaining air bubbles from the syringe, attach to the luer lock adapter, and slowly fill the tubing. It is easiest to do this with the mandrel hand area lower than the shoulder to ensure all air bubbles are removed and the tubing fills uniformly. See Figure 3.
9. When the “blood” has filled both sides, pinch and clamp the return side with the Kelly clamp tightly to the third click, ensuring no air bubbles are trapped. The presence of large air bubbles reduces the pulsatile feeling because air is compressible as well. Minimizing these will enhance the learners’ experience of feeling a radial pulse which is essential to successful completion of the skill. See Figure 3.
10. Leave the syringe attached. There should be at least 20cc of “blood” remaining in the syringe. This is desirable because this is what will not only generate the pulse for the skill, but also replace blood that gets removed from the artery throughout the practice of placement. Add more “blood” to the syringe if there is less than 20cc of blood remaining once the system is clamped. See Figure 3.
11. Check to see that there is a palpable pulse over the radial artery. Do this by quickly compressing and releasing the plunger on the syringe. Repeat for the ulnar artery.
12. Ensure there are not any kinks or pinch points in the tubing before replacing the skin. Adjust as needed.
13. Replace the skin carefully. This can be facilitated with liberal application of standard liquid dish soap to the inside of the skin and to the stretch points on the mandrel such as the thumb area. See Figure 4.
14. Verify a pulse can be still be felt at the radial artery location now that the skin has been replaced using the same technique above. If the pulse is severely dulled, there may be too many or too few gauze pads in the area of the pulsation or that area may have been too tightly taped. Repeat for the ulnar artery. Consider these troubleshooting options:
a. Too much tape over the radial artery: Cut the tape to loosen, careful not to cut the tubing.
b. Too few gauze pads causing excessive compression of the tubing: Add more gauze.
c. Too many gauze pads causing pulsation to not be transmitted through the skin: Remove some gauze pads in the area.
The prototype of the radial artery catheterization trainer was pilot tested by five acute care acute gerontology nurse practitioner (ACAGNP) learners, and their instructor. The instructor is comfortable with the procedure of arterial lines and has been kept up to date on the process of creating this trainer. Learners have not performed this procedure prior to their experience with this trainer. The learners are clinically practicing nurses in acute care or emergency settings. The training occurred at one of six acute care skills stations during their acute care skills training day and attendance was required. Learners were required to practice the skill during the skills lab, however were not required to complete the survey. All learners were anonymously, voluntarily consented according to DeSales University IRB approval number ET-88-04162023 to participate in this survey prior to the start of their skills station rotations. They completed surveys following their experience with the trainer. The five consented learners represented the entire cohort of this year’s ACAGNP program.
Survey Development
The survey asked participants to rate several aspects of the realism of the trainer, their comfort with the skill before and after using the trainer, and whether or not they would recommend using this trainer for further practice of radial artery catheterization. The survey was reviewed for clarity by three experts in both simulation and radial artery catheterization. The data was summarized in a spreadsheet.
Results
The survey recorded learners’ perception of realism on a 5 point scale ranging from Highly Unrealistic with a score of one through Highly Realistic with a score of 5. The five learners practiced with the trainer and all five completed a survey. The mean scores and standard deviation given can be found in Table 2. The learners rated the overall anatomic accuracy of the trainer as highly realistic with a mean of 4.6 (95%, CI = 4.11 – 5.08). The learners’ comfort level increased by an average of 2.4 +/- 0.447 rising from an average of 1.8 (uncomfortable) before practicing to a 4.2 (comfortable) after using the model. The learners would overwhelmingly recommend continued use of this trainer with a mean of 4.6 +/- 0.54. Learners commented that this was very useful and worked great.
Discussion
This trainer can be assembled in under an hour for less than $US5 per trainer and does not require specific technical skill to complete. An internet search indicated that radial artery catheterization trainers without ultrasound capabilities ranged in cost from $US700 - $US1,400 to over $US3,000 for ultrasound guided models.
We had all the supplies in house already for other course needs except the latex tubing and the luer lock to hose barb adapter. For trial purposes we also purchased silicone tubing in the same size as the latex. We opted for the latex because it transmitted the pulsations much more realistically and palpably than the silicone tubing. The pulsations felt using the silicone tubing were far too weak to be optimal for initial training, however, could be used when a weaker pulse was needed or for more advanced, experienced learners.
The trainer withstood an estimated 25 sticks over the course of the training day. At the conclusion of the day, the trainer did not leak externally during the application of pressure when providing the pulsations. The 2x2s inside were not saturated either, which could mean that internal leakage was limited, though it would be necessary to reevaluate this after more punctures were done on the trainer. Overall, this made cleanup easier, and learners were unlikely to be stained from the simulated blood.
In prior years, faculty noted that one other commercially available trainer lost palpable pulses after just two punctures. Since the pulse is essential to a realistic and successful training, this model required that the pulse be maintained with little to no loss in fidelity for all learners. This simulator still maintained a strong, palpable pulse when pressure was applied with the syringe. This indicates that larger classes or more sticks can be completed on this trainer in a relatively short period of time without an appreciable loss in anatomic fidelity. It can further be stated that this will reduce the overall cost of the trainer and training because it will require less frequent consumable supplies replacement.
Learners were able to get a blood flash in the radial artery catheter chamber which replicated a real experience over the entire day. This indicates proper placement of the needle within the vein and allows the instructor to stop the pulsations. Being able to stop the pulsations for the remainder of the procedure likely has the effect of extending the life of the simulator’s current parts. Subsequently, this results in a cheaper simulator to maintain.
Faculty and learners identified the inability to float a guidewire as a confounding complication inconsistent with reality with other commercially available trainers in prior years. Using this trainer, learners were able to float the guidewire an appropriate distance into the vein because the arterial run was straight, and no kinking was observed at several points during assembly. The catheter also was able to be successfully inserted without folding through this skin in a realistic fashion.
The survey indicated the least satisfaction was with the ability to insert the needle into the skin. The researcher suspects this perception is similar to that experienced during the placement of a peripheral IV catheter in a similar trainer; however, more research would be needed. The simulator skin is necessarily thicker than that of the average forearm, particularly in the area over the radial artery at the point of insertion, and therefore presents a challenge to effectively replicate. That being said, the Limbs and Things skin for this model did not show an extensive amount of wear and was still intact, indicating that it could withstand further punctures before requiring replacement. This was of particular importance to a satisfactory design since the target area of the sticks is highly concentrated.
The presence of an ulnar artery in addition to the necessary radial artery is an added feature of this model that allows the learner to practice a component of the Allen test. The Allen test tests for collateral circulation from the ulnar artery and is performed by occluding both ulnar and radial arteries in the wrist observing for pallor to develop in the palm. The practitioner would then release the ulnar artery and, if collateral circulation is sufficient, the color returns to the palm despite continued occlusion of the radial artery (Tegtmeyer, et.al., 2006). An area of future improvement to this simulator would include the addition of a bright white LED light under the skin in the palmar area attached to pressure sensors near the radial and ulnar arteries to replicate the result of an Allen test. Occlusion of both arteries, and therefore activation of both pressure sensors, would illuminate the light, replicating the pallor. Releasing the ulnar pressure sensor would dim the light, indicating return of collateral circulation, allowing the procedure to continue.
This simulator does not allow the procedure to be completed under ultrasound (US) guidance. This would be an area of future improvement, though would likely require an entirely different procedure rather than a simple modification to this process. US guidance for arterial line placement is increasingly becoming a standard of care, (Pierre, et. al., 2023) though the research seems to be conflicted on its utility (Zhang, et al, 2020).
Though the sample size of learners was small, it did represent this year’s entire cohort, not much different in size than previous cohorts. This study can and should be replicated at larger institutions to further verify these assertions.
The survey results indicate that the users were satisfied with all aspects of the realism incorporated into this trainer. They noted that this trainer enhanced their confidence with the procedure and highly recommended it for continued future use. While all participants were clinically practicing nurses, the researcher did not determine prior experience with venous catheterization. Further, it is unlikely that any participants had ever floated a guidewire in either a simulated or real environment prior, indicating no basis of comparing the realism represented in this trainer relative to guidewire insertion. This represents an area for future evaluation from learners with experience in using a guidewire for catheter insertion to verify realism in this aspect. Although the faculty experts running this training indicated satisfaction of this trainer to address areas indicated above, it would further be of interest to have providers experienced in radial artery catheterization verify the overall utility.
Conclusion
The innovative, low-cost radial artery catheterization trainer created from an obsolete IV arm shows distinct promise as a viable alternative to more expensive commercially available trainers for radial artery catheterization. The trainer combines superior anatomic realism in the areas of location and feel of the radial artery, ability to insert the guidewire and catheter into the trainer and overall accuracy. Learners were able to increase their comfort and, by extension, confidence in performing the skill prior to entering the clinical environment and encourage the continued use of this model for repetitive practice.
Additional Information
This study was conducted in the DeSales University (DSU) Healthcare Simulation Center (Gambet Center 2755 Station Ave. Center Valley, PA 18034) when the author was employed there. The DSU IRB adjudicated this study as no more than minimal risk to study participants. The researcher identifies no conflicts of interest in conducting or publishing this study. No financial support was received to conduct this study.
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