The easy-to-use ResQR© Quality CPR Aid could be used to enhance layperson chest compressions in performing CPR.
Introduction
More than 300,000 Americans die from cardiac arrest each year.1 Cardiopulmonary resuscitation (CPR) provided by a bystander may improve outcome2 but is generally performed in less than 30% of the cases.3 The primary reason for the low survival rate among out-of-hospital cardiac arrest victims (OHCA) is that they do not receive immediate CPR.
When there is only one rescuer, or when the responders are untrained rescuers, or when there are multiple rescuers who are unwilling to do mouth-to-mouth ventilation, chest compression-only (CPR without ventilation) is encouraged.4. Untrained bystanders find chest compression-only CPR easier to perform, especially when given verbal instruction by dispatchers over the phone.6 Randomized trials support the performance of chest compression-only CPR, 5 including a recent report found that the ability to perform compression-only CPR markedly increased the willingness to perform CPR from 36.4% in 2005–2007 to 63.7% in 2011–2012 when compared with the prospect of performing full CPR with mouth-to-mouth ventilation.7
Chest compression is the most essential element of CPR. Correctly performed compressions maximize coronary perfusion pressure mimicking the heart’s pumping activity, and provides about 30% of the blood supply as normal cardiac activity 8 and increasing the chance of return of spontaneous circulation (ROSC). Chest compression rate is an important determination of survival with good neurological function.3 According to 2020 AHA guideline9 the OHCA patient who receives chest compression rate between 100 and 120/minute has a greater chance to survival to discharge than a patient with a much faster or slower rate.9
The ResQR© (Rithem Life Sciences, Wilmington DE, USA) Figure 1) is a comprehensive quality CPR aid. It incorporates two metronomes (one audio and one visual) set to 110 bpm.
It has a placement guide for proper placement on the chest with a no slip surface to ensure that it stays in the proper position. It also has an ergonomic contour that provides biofeedback to ensure improved hand and shoulder positioning. It also includes a privacy sheet to cover a woman’s chest for performance of CPR in a public area and a personal protection environment sheet that allows the provider to perform CPR in a non-contact environment. This study set out to evaluate the efficacy of the ResQR device in improving performance of CPR chest compressions in laypersons with no CPR training.
Materials and Methods
Israeli High School Students were recruited to take part in this study. Although all high school students are usually given a CPR course in Israel as part of their 10th-grade curriculum, they were not given a class because of the pandemic. Recruits were shown a quick demonstration of CPR, with proper pace, hand placement, hand and shoulder positioning highlighted. They were then given a short explanation of how to use the ResQR. They were then asked to perform CPR for two minutes. After a short rest, they were given the ResQR device and asked to perform CPR again for another two minutes.
The recruits were graded subjectively by a single senior CPR Instructor for the following:, hand placement on the chest, hand position and shoulder position. They were evaluated every 30 seconds of the two-minute cycle. The subjective grade was scored from one to five. They were also evaluated objectively by the Laerdal Q-CPR app for compression depth and pace. Compression depth was measured as the total percentage of compressions that were performed at sufficient depth. Rate of compressions was measured as a total number of compressions given over two minutes, as well as the percentage of compressions given at the proper pace.
Results
Ten high school students (aged 15-17) were recruited for the study. There were seven males and three females. Table 1 shows the average results for scores by the subjective evaluator of the position of hand placement on the chest.
Hand placement with the ResQR averaged a grading of 5, which stayed consistent through the two minutes. Without the ResQR initial hand, placement was 4.3 and continued to degrade over the course of the two minutes. Table 2 shows the average results for the hand position during compressions.
With the ResQR, initial placement scored a 4.5 and stayed consistent until the last 30 seconds. Without the ResQR initial placement was graded as a 4, and immediately degraded after the first thirty seconds. Table 3 shows the average results of shoulder position during compressions. With the ResQR, the average started at 4.5 and only degraded in the last thirty seconds. Without the ResQR the grading started at a four and immediately degraded.
Objective results from the Laerdal QCPR App showed that the average number of compressions performed over 2 minutes without the ResQR was 218 (Range 184-255), compared to the number of compressions with the ResQR, which was 212 (Range 205-230). Only 76% of compressions without the ResQR were graded as within good pacing range as compared to 97% of compressions with the ResQR. There was an insignificant difference in the average number of compressions given with adequate depth.
Discussion
This was a small study to evaluate the efficacy of the ResQR in improving chest compressions in laypersons with no training in CPR. The study design was open-labeled but single evaluator. There was a built-in bias against performance with the ResQR that was only realized after the study. A number of the recruits were asked to perform two minutes of CPR almost immediately, followed by another two minutes with the ResQR with inadequate rest in between. This should have caused a more significant decline in compression performance with the ResQR. The result that there was more consistent performance of compressions across the whole two minutes even though there should have been a factor of fatigue points to the ever increasing efficacy of the device.
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The pace of compressions is the most important factor in compressions. Second to this is hand placement on the chest followed by compression depth and recoil. If compressions are performed too quickly, the efficacy of simulating the heart pump, and especially refilling the heart chambers with blood to circulate are compromised. If compressions are performed too slowly, blood collected in the heart is not being circulated with adequate efficacy. The ResQR’s two built in pacing devices caused more compressions being performed at an appropriate pace, ensuring better circulation.
The combination of proper pacing of compressions combined with enhanced hand placement on the chest and shoulder position over the mannequin combine for better compression depth during CPR. Had the hand placement varied, some compressions would have been better and some would have been too caudal with resultant decreased efficacy. The improvement in shoulder positioning provides the responder with a better angle for both compression and recoil to allow the chest to expand better.
Conclusion
The ResQR© Quality CPR Aid could be used to enhance layperson chest compressions in performing CPR.
References
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9. Eric J. Lavonas, MD, MS; David J. Magid, MD, MPH; Khalid Aziz, MBBS, BA, MA, MEd(IT); Katherine M. Berg, MD; Adam Cheng, MD; Amber V. Hoover, RN, MSN; Melissa Mahgoub, PhD; Ashish R. Panchal, MD, PhD; Amber J. Rodriguez, PhD; Alexis A. Topjian, MD, MSCE; Comilla Sasson, MD, PhD; and the AHA Guidelines Highlights Project Team. Highlights of the 2020 American Heart Association Guidelines for CPR and ECC.
