Transcutaneous cardiac pacing competency among junior residents undergoing an ACLS course: impact of a modified high fidelity manikin

Unstable bradycardia is an uncommon occurrence with an estimated incidence of six out of 10,000 patients seeking care in the emergency room (ER) [1]. Transcutaneous cardiac pacing (TCP) is an effective treatment recommended by the 2010 American Heart Association (AHA) guidelines for unstable bradycardia [2, 3]. It can, however, be difficult to implement: pitfalls must be avoided, and assessment of ventricular capture is complicated [4–6]. This low frequency but high-stakes procedure may pose a challenge for junior clinicians unfamiliar with unstable bradycardia.

Since pacing situations are rare and heterogeneously observed in the clinical context, experience alone is generally insufficient to acquire and maintain competency in TCP. Simulation provides an opportunity to practice TCP in a context conducive to learning, and the 2015 American Heart Association guidelines state that the use of high-fidelity mannequins for ACLS training can be beneficial [7]. However, even the highest-fidelity mannequins available have significant shortcomings regarding simulation of TCP, which might limit their usefulness. The Two-Mannequin Model (TMM), a new mannequin that simultaneously exploits technical features of two commercially available mannequins, has been proposed to overcome some of the weaknesses of the available mannequins regarding TCP simulation [8]. It is however important to establish whether this higher-fidelity simulation of TCP indeed leads to better learning of TCP [9, 10]. 

The objective of this study was to evaluate the impact of teaching with the modified high-fidelity TMM on the learning of TCP by junior residents during an ACLS provider course. Their competence was judged by their ability to complete the tasks necessary for successful TCP in a simulation scenario and compared to a similar cohort having been taught with the lower-fidelity mannequin traditionally used for teaching, using the same assessment scenario.

The objective of this study was to evaluate the impact of a modified high-fidelity TMM compared to lower-fidelity mannequins traditionally used in the learning of TCP. Learning TCP was difficult for junior residents, as demonstrated by their generally low success rate. However, the use of a modified high-fidelity TMM during an ACLS course, when compared to a traditional simulation mannequin, significantly improved their ability to complete all tasks necessary for successful TCP during a simulated case resembling clinical practice. This study contributes to the literature by demonstrating for the first time the ability of such a mannequin to improve the learning of TCP and for a specific intervention other than repeated practice to improve the ability to establish TCP.

These results are consistent with the broader literature which suggests that the use of high-fidelity mannequins for advanced life support (ALS) training is associated with improved skill performance at course conclusion [18]. However, with most studies measuring overall performance, it is difficult to understand exactly when improved fidelity leads to better performance [9]. Studies like this one, which focus on a specific skill and on specific characteristics of the simulated experience, can help to pinpoint where efforts to improve simulation fidelity are likely to lead to benefits.

The differences between the both cohorts’ results can be explained by multiple factors. Being deceived by intuitively appealing but false signs of ventricular capture upon initiating TCP is a recognized pitfall of the technique [5, 6]. Many participants in our study assumed ventricular capture upon seeing the mannequin twitch or upon noting on the ECG a higher-frequency signal of pacer spikes followed by wide QRS-like complexes. These participants either did not take a pulse despite having been instructed specifically to do so during training or took the pulse but did not appreciate it was still very slow. When questioned during debriefing, these residents frequently mentioned that they were so convinced the TCP was effective that they did not feel the need to take the pulse or to calculate its frequency, suggesting a confirmation bias in their processing of the clinical information [17]. Improved simulation in the second year of the study might have led to a better performance by allowing participants to experience and understand the false signs of ventricular capture during training. Interestingly, checking the pulse was also the step most often omitted in the study involving the deliberate practice of TCP in emergency medicine residents [4].

The use of a modified high-fidelity mannequin in the second year of this study might also have improved teaching by the instructors: more emphasis may have been put on false signs of effective TCP and on the importance of the pulse to confirm capture. A better TCP simulator might also have improved the instructors’ own understanding of TCP. If better teaching in the intervention cohort explains the superior results, it might be possible to achieve similar gains by improving teaching without using a high-fidelity simulation at all.

Although the modified high-fidelity TMM significantly improved the ability of junior residents to achieve all six tasks for successful TCP, a large proportion of residents were still unable to do so. Many explanations for the limited impact of ACLS training have been offered [14]. In this study, failure is likely attributable in part to the inexperience of our participants: first-year residents dealing with an unstable patient are expected to struggle both to rapidly extract and organize the pertinent clinical cues from the overwhelming amount of information provided by the realistic clinical setting and to respond correctly [15, 16].

Another explanation for the high failure rate in the present study might relate to the complexity of TCP. In a previous study involving more senior emergency medicine residents with some TCP experience, an average of three attempts were needed to successfully perform TCP on a simulator [4]. Furthermore, in that study, the attempts were made in a context of deliberate practice where feedback was given after each attempt, a setting more favorable than the one used to test participants in our study.

A suboptimal teaching method might also contribute to a high failure rate. Demonstrating and practicing a complicated technique on a simulator presenting an excessively simplified version of reality might lead to underperformance in more complex and more realistic situations. In the second year of this study, the use of an improved simulation tool during hands-on TCP training, in a similarly inexperienced population undergoing an otherwise identical course, led to a significant improvement in performance when measured in the same simulated clinical situation. More specifically, the intervention cohort outperformed the controls in three critical tasks simulated more effectively by the TMM. This supports the hypothesis that, in specific cases, increased fidelity can lead to better learning.

The use of simulation as an assessment tool is gaining acceptance [19, 20], and in this study, it provided a reliable way to measure TCP success. Furthermore, since the simulation experience recreated key physical, as well as the cognitive and emotional aspects of acute clinical care, this type of evaluation might be a more valid marker of actual clinical performance than the written tests and the “megacode” simulations traditionally used to assess ACLS competency.

The present study is not devoid of limitations. Some of the improvement in the intervention cohort might be attributable to participants becoming more familiar with the TMM mannequin used both during hands-on training and during simulation testing. To minimize this potential bias, a video illustrating the TMM’s general features was presented before the simulation scenario. The choice of a video instead of a hands-on orientation on the TMM for the control group prior to simulation testing was made because of time constraints and because of the risk that an orientation including TCP might either cue the participants about the contents of the simulation to come or serve as another learning opportunity, both factor potentially confounding our ability to assess what the participants really learned in the ACLS course. In addition, since the high-fidelity characteristics of the TMM used during training were only the ones relating to TCP, it is likely that any increased familiarity with the mannequin would relate chiefly to its response to pacing. If the simulator, despite its limitations [8], approaches clinical reality enough, then one can expect the gains in familiarity with pacing the TMM to transfer to pacing actual patients: the increase in familiarity and performance would represent a true gain in competence that would not be restricted solely to the TMM.

Another potential source of bias, given our study design, is that some participants might have known about the simulation scenario beforehand. However, all participants signed a confidentiality agreement and confirmed they had no knowledge of the scenario before beginning the project. Furthermore, participants had little incentive to share the information since they knew their performances were kept strictly confidential. The instructors might also have learned about the objectives of the study and modified their teaching method. However, great care was taken to prevent the instructors from knowing the content of the assessment scenario.

The use of junior residents limits the generalizability of our findings. While the homogenous recruitment population enabled the formation of comparable cohorts, this study’s findings might not apply to other populations of learners. Indeed, the appropriate level of fidelity to maximize learning is known to vary according to learner experience [11, 21]. This will remain a challenge with ACLS courses, which are offered to very heterogeneous populations of learners. Additionally, the junior residents were mostly family practice residents, and this may limit the applicability of our findings as TCP is less likely to be performed outside the ER. However, when it is performed outside the ER, it may be done so by clinicians less familiar with this procedure, as was the case in this study.

Finally, given the design of this study, it is only possible to speculate about how the participants’ performance translated in real-life situations, and it is not possible to know their long-term retention of TCP.

The use of a modified high-fidelity mannequin during an ACLS course improves the ability of junior residents to achieve six critical tasks for successful TCP. However, an important performance gap remains and future research should aim to identify methods to address this gap [22].