In March 2016, our institution purchased a new defibrillator system, the ZOLL R Series monitor/defibrillator. The reported benefits of this system were many, including the Cardiopulmonary Resuscitation (CPR) Dashboard, a detailed real-time display of CPR quality metrics that uses ZOLL's Real CPR Help technology, and See-Thru CPR that filters out CPR artifact, to minimize pause time during CPR and increase CPR fraction, the percentage of time in which chest compressions are done by rescuers during a cardiac arrest. With the purchase of this new defibrillator and its ability to give CPR feedback, the expectation was set within the hospital that all cardiac arrests would have the defibrillator pads placed on the patient and CPR feedback used regardless of rhythm, with the hope that high-quality CPR will be provided for every resuscitation. This new recommendation was a change from the previous practice and would result in the defibrillator system being used more often than the previous system.
To prepare staff for such a change, it was important that educators across the institution, and more specifically the simulation team, were able to mimic how the defibrillator should be used in the clinical setting. As a simulation center that supports over 90 courses and trains over 9000 healthcare providers annually, we were tasked with implementing the new system within our courses, scenarios, and debriefing sessions. We also needed to accommodate a drastic increase in the frequency of cardiopulmonary arrest scenarios, at least for the implementation period, within our courses and require providers to perform CPR using the ZOLL R Series defibrillator training pads and display functions.
In an effort to maximize the fidelity of our simulations, while embedding the benefits of the new defibrillator system, we decided to investigate how the ZOLL system would interact with our simulators/task trainers, participants, and software. During training sessions, it was important that our participants had the opportunity to accurately and reliably interact with the features of the defibrillator, identify mistakes they are making in performance of CPR and rhythm management, and correct those mistakes through deliberate practice. If the new system's CPR feedback was not feasible, valid, and reliable with our simulation equipment, we worried that sessions would become frustrating for participants and negatively impact their learning. Basically, we expected our participants to walk away with real-world knowledge and skills of how to interact with the defibrillator pads and display functions, and thus be able to apply that knowledge and skill in the patient care setting. Our objective was to determine which commercial simulators would be compatible with the ZOLL R Series defibrillator system and its CPR feedback functionality in a simulation-based training setting.
Our team gathered together to evaluate how this change might impact our training and how we could ensure an accurate representation of all the features the ZOLL defibrillator offered. We designed a spreadsheet that included our simulators and a list of all the features of the ZOLL that needed to be assessed through simulation. The simulators our center most commonly uses are Laerdal Medical and Gaumard Scientific brand simulators. We have infant, child, and adult-sized simulators (Fig. 1). Our methods included testing each simulator, using infant pads and ZOLL's pediatric and adult training pads, where applicable, and attempting to achieve recommended depth and rate guidelines set by the American Heart Association (AHA). The infant pads do not have the CPR Dashboard function, or filtered rhythm option, whereas the child pads (for use <25 kg) provide feedback on depth and rate. The adult pads provide feedback on depth, rate, release (via a compression release indicator), and perfusion performance indicator, a diamond that if filled signifies both depth and rate being within AHA guidelines (Fig. 2). In addition to CPR feedback, the ZOLL offers See-Thru CPR or filtered rhythm feature. This allows providers to assess the patient's rhythm even while chest compressions are in progress. A third function of CPR feedback offered by the ZOLL Series and assessed in this report was the idle timer, which displays (in seconds) the length of time since chest compressions have stopped. To incorporate the need for CRP feedback, rhythm filtering, and idle time into the training simulations, ZOLL's training pad compatibility was assessed using rhythms generated from the simulators themselves and with a rhythm generator supplied by Symbio Corporation.
Figure 1 shows our primary finding that certain simulators function better than others with the ZOLL R Series system when used in the context of CPR training. As it stands today, we have no high-fidelity infant-sized simulators that can meet the depth recommendation for chest compressions given by the AHA. One training work-around we have found is to use a low-fidelity infant-sized manikin to create a deliberate practice station where learners can see feedback that accurately reflects depth and rate for a patient this size. We also have only 1 manikin, SimJunior by Laerdal, which can display an accurate depth for a child-sized patient.
Our team found that the only rhythm generator that offered a filtered rhythm option was the Symbio See-Thru CPR Simulator device. In addition, the only rhythm that was able to be filtered was ventricular fibrillation. We found that the Symbio See-Thru CPR Simulator device also lacked supraventricular tachycardia and sinus tachycardia options, which are important in pediatric simulations. Thus, we demonstrated the need for having both the Symbio See-Thru CPR Simulator device and the Symbio CS301 to conduct all the necessary rhythm options required in our pediatric simulation-based training courses.
Software provided with each simulator offers opportunities to generate cardiac rhythms; however, detection of these rhythms using ZOLL R Series pads created significant limitations. If a Laerdal child or adult simulator was used along with Laerdal Defib Training Cables, any rhythm that the simulator could generate was available and once chest compressions were started theoretically the rhythm could be seen as filtered. The exception was SimBaby where chest compressions (rate or depth) were not detected using the ZOLL pads. Generating the rhythm directly from the manikin offered more options from a rhythm perspective; however, frequently once chest compressions were started the Laerdal Defib Training Cables would disconnect creating a loss of feedback for learners as the rhythm displayed would disappear and the defibrillator would read “poor pad contact.” This message prompted learners to recheck connections and even attempt to change pads during the scenario, neither which corrected the problem. This problem forced a simulation staff member to enter the training room and “discreetly” reconnect the training cable to resolve message. This was found to be distracting and confusing for learners. With our Gaumard simulators, a rhythm was not captured when the ZOLL training pads were applied to the conductive skin sites on the manikin. These conductive skin sites are also not anatomically located where the ZOLL pads are recommended to be placed, which negates using Gaumard simulator generated rhythms as a valid option during training.
In all instances where the defibrillator was able to accurately detect chest compressions, the idle timer functioned appropriately. The display showing idle time would disappear at the start of compressions, then approximately 3 to 4 seconds after compressions were stopped, the “IDLE” display reappeared and began counting forward in seconds until compressions were restarted. Learners were able to reliably interact with this function, with the teaching expectation being CPR was not stopped for greater than 10 seconds.
All of the hurdles listed previously have changed the way our pediatric simulation center conducts training and develops scenarios. If a primary learning objective for a scenario involves using the ZOLL R Series, we have a limited number of pediatric manikins and rhythms that can accurately represent its features. The inability to accurately filter the more common pediatric cardiac arrest rhythms, such as pulseless electrical activity or asystole, is unfortunate for learners and decreases the validity and reliability of those simulated training sessions. This is a particularly troubling finding given that most (74%) cardiopulmonary arrests in our institution occur in patients less than 25 kg. Logistically, these training limitations create significant hurdles for any simulation center, but specifically for those located in settings where their providers care for critically ill and injured children.
In addition, findings related to the compatibility of the ZOLL R Series, and likely any defibrillator feedback system, are pad placement and manikin structural integrity. Pad placement plays a significant role in feedback generated on the ZOLL R Series, as pads that are slightly misplaced can result in learners being unable to achieve recommended depths. This finding would also be expected in a clinical setting. In addition, manikins with worn, more pliable chests or brand new manikins with stiffer chests can affect depth readings on the ZOLL R Series.
Our team is now aware of the limitations, and with the knowledge gained, we can guide training in a way that learners can get the most from their experience. It is unlikely we are the only simulation center faced with these limitations, and it is our hope that our findings can streamline educational efforts within other institutions and centers. Moreover, these identified limitations should prompt future advances in technology so that our ability to accurately represent the beneficial features of the ZOLL R Series is generalized across all patient ages and arrest rhythms.
Keywords:© 2018 Society for Simulation in Healthcare
CPR; defibrillator; simulation