Chest Recoil Research Articles

Analysis of Chest-Compression Depth and Full Recoil in Two Infant Chest-Compression Techniques Performed by a Single Rescuer: Systematic Review and Meta-Analysis.

Pediatric cardiac arrest is associated with high mortality and permanent neurological injury. We aimed to compare the effects of the two-thumb (TT) and two-finger (TF) techniques in infant cardiopulmonary resuscitation (CPR) performed by a single rescuer. We searched PubMed, EMBASE, and CENTRAL for randomized control trials published before December 2019. Studies comparing the TT and TF techniques in infant CPR were included for meta-analysis. Relevant information was extracted for methodological assessment. Twelve studies were included. The TT technique was associated with deeper chest-compression depth (mean difference: 4.71 mm; 95% confidence interval: 3.61 to 5.81; p < 0.001) compared with the TF technique. The TF technique was better in terms of the proportion of complete chest recoil (mean difference: −11.73%; 95% confidence interval: −20.29 to −3.17; p = 0.007). CPR was performed on a manikin model, and the application of the results to real human beings may be limited. The TT technique was superior to the TF technique in terms of chest-compression depth, but with inferior chest full recoil. Future investigations should focus on modifying the conventional TT technique to generate greater compression depth and achieve complete chest recoil.

Wearing a N95 mask increases rescuer's fatigue and decreases chest compression quality in simulated cardiopulmonary resuscitation.

ObjectivesN95 mask is essential for healthcare workers dealing with the coronavirus disease 2019 (COVID-19). However, N95 mask causes discomfort breathing with marked reduction in air exchange. This study was designed to investigate whether the use of N95 mask affects rescuer's fatigue and chest compression quality during cardiopulmonary resuscitation (CPR).MethodsAfter a brief review of CPR, each participant performed a 2-minute continuous chest compression on a manikin wearing N95 (N95 group, n = 40) or surgical mask (SM group, n = 40). Compression rate and depth, the proportions of correct compression rate, depth, complete chest recoil and hand position were documented. Participants' fatigue was assessed using Borg score.ResultsSignificantly lower mean chest compression rate and depth were both achieved in the N95 group than in the SM group (p < 0.05, respectively). In addition, the proportion of correct compression rate (61 ± 19 vs. 75 ± 195, p = 0.0067), depth (67 ± 16 vs. 90 ± 14, p < 0.0001) and complete recoil (91 ± 16 vs. 98 ± 5%, p = 0.0248) were significantly decreased in the N95 group as compared to the SM group. At the end of compression, the Borg score in the N95 group was significantly higher than that in the SM group (p = 0.027).ConclusionWearing a N95 mask increases rescuer's fatigue and decreases chest compression quality during CPR. Therefore, the exchange of rescuers during CPR should be more frequent than that recommended in current guidelines when N95 masks are applied.

Resuscitation of the patient with suspected/confirmed COVID-19 when wearing personal protective equipment: A randomized multicenter crossover simulation trial.

The aim of the study was to evaluate various methods of chest compressions in patients with suspected/confirmed SARS-CoV-2 infection conducted by medical students wearing full personal protective equipment (PPE) for aerosol generating procedures (AGP). This was prospective, randomized, multicenter, single-blinded, crossover simulation trial. Thirty-five medical students after an advanced cardiovascular life support course, which included performing 2-min continuous chest compression scenarios using three methods: (A) manual chest compression (CC), (B) compression with CPRMeter, (C) compression with LifeLine ARM device. During resuscitation they are wearing full personal protective equipment for aerosol generating procedures. The median chest compression depth using manual CC, CPRMeter and LifeLine ARM varied and amounted to 40 (38-45) vs. 45 (40-50) vs. 51 (50-52) mm, respectively (p = 0.002). The median chest compression rate was 109 (IQR; 102-131) compressions per minute (CPM) for manual CC, 107 (105-127) CPM for CPRMeter, and 102 (101-102) CPM for LifeLine ARM (p = 0.027). The percentage of correct chest recoil was the highest for LifeLine ARM - 100% (95-100), 80% (60-90) in CPRMeter group, and the lowest for manual CC - 29% (26-48). According to the results of this simulation trial, automated chest compression devices (ACCD) should be used for chest compression of patients with suspected/confirmed COVID-19. In the absence of ACCD, it seems reasonable to change the cardiopulmonary resuscitation algorithm (in the context of patients with suspected/confirmed COVID-19) by reducing the duration of the cardiopulmonary resuscitation cycle from the current 2-min to 1-min cycles due to a statistically significant reduction in the quality of chest compressions among rescuers wearing PPE AGP.

Comparison of Chest Compression Quality between Transfer Sheet and Stretcher Use for Transporting out-of-Hospital Cardiac Arrest Patients in a High-Rise Building - A Randomized and Open-Label Cross-over Design

Objectives Stretchers are commonly used for transporting cardiac arrest patients, but their use may be limited in confined spaces, like elevators. Use of transfer sheet as an alternative has not been explored. We aimed to compare manual chest compression quality between these two methods. Methods: In this prospective, open-label, randomized cross-over manikin study, the subjects included emergency medical technicians who were assigned to 12 three-person crews. Scenarios included transport of a cardiac arrest in a high-rise building and elevator using transfer sheet (TS) and stretchers adjusted to 45° (S45) and 90° (S90). Chest compression quality was measured using a recording manikin and that before (on-scene phase) and after (transport phase) the manikin moved via transfer sheet or stretcher were compared. Results: The final analysis included 72 simulation runs. Chest compression quality did not differ among the groups in the on-scene phase. In the transport phase, the transfer sheet group provided greater mean compression depth (54.4 ± 4.2 vs 39.6 ± 7.2 mm, p < 0.01 and 54.4 ± 4.2 vs 40.6 ± 8.3 mm, p < 0.01, respectively) than stretchers of S45 and S90, and higher percentage of deep-enough compression (TS: 51.0 [23.8-74.8]% vs S45: 19.5 [5.8-29.5]%, p < 0.01) than the S45 group. Transfer sheet use showed a trend of lower percentages of full recoil (TS: 40.0 [12.8-64.5]% vs S45: 70.5 [47.0-79.8]% vs S90: 52.5 [25.3-76.0]%, p = 0.09). Chest compression fraction, compressions with correct hand position, and mean compression rates did not differ between groups in the transport phase. The TS group showed shorter time intervals of simulation start-to-first-compression (TS: 13.9 [12.4-15.1] sec vs S90: 15.9 [13.3-16.4] sec, p = 0.04) and total run time (TS: 145.7 [135.1-151.4] sec vs S90: 160.0 [151.9-175.4] sec, p < 0.01) than the S90 group. Conclusion: In this simulation, using transfer sheet outperform using stretcher for transporting cardiac arrest patients from high-rise buildings. Rescuers need to be aware of full chest recoil.

The use of prefilled adrenaline syringes improves cardiopulmonary resuscitation quality-high-fidelity simulator-based study.

BackgroundIn some countries, adrenaline is available only in glass ampoules. However, simplification of cardiopulmonary resuscitation (CPR) by introducing prefilled syringes may ensure more efficient CPR. The aim of this study was to investigate the impact of different forms of adrenaline on the CPR quality.MethodsIn a randomized cross-examination simulation study, 100 two-person paramedical teams took part in two 10-minute scenarios of sudden cardiac arrest (SCA) in a pulseless electrical activity mechanism (PEA). In the first scenario the set of medicines contained glass ampoules (group ST) with adrenaline, in the second prefilled syringes (group AMPS). The parameters of the CPR quality [correct number and depth of chest compressions (CC), no flow time, chest recoil, time to apply supraglottic airways device (SAD)] were compared.ResultsIn group AMPS the first dose of adrenaline was administered after 114.2±28.3 seconds after the initiation of CPR whereas after 178.1±62.6 seconds in group ST (P<0.001). Chest compression fraction (CCF) was higher (81.8%±6.1%) in group AMPS than in group ST (71.2%±7.5%). Paramedics performed CC at better frequency, to a preferred depth and in an appropriate place in group AMPS. Faster decision to apply SAD (131.7±34.0 s in group AMPS and 220.3±81.5 s in group ST) ensured faster achievement of airway patency in this group (181.5±48.7 vs. 271.2±101.5 s).ConclusionsPrefilled syringes with crucial drugs during CPR may significantly improve the quality of CPR performed by two-person teams.

Analysis of the quality of chest compressions during resuscitation in an understaffed team — randomised crossover manikin study

INTRODUCTION: According to the chain of survival, chest compressions (CCs) are crucial in every cardiac arrest patient. It is very challenging to provide high-quality resuscitation in a two-paramedic team. The task of an automatic chest compression device (ACCD) is to relieve the rescuer and improve the quality of CCs. Its influence on the quality of the whole resuscitation as well as the survival of patients is still subject to discussion worldwide. This study aimed to assess the quality of CCs during resuscitation in a two-paramedic team using ACCD. MATERIAL AND METHODS: This research was designed as a prospective, randomised, cross-over, high-fidelity simulation study. Fifty-two double paramedic teams took part in the research. The role of the participants was to conduct full advanced resuscitation in a human patient’s simulator. Each team provided resuscitation twice. Once with an ACCD and once using manual compressions. Chest compression quality parameters, as well as chest compression fraction (CCF), were measured. RESULTS : Statistically significant differences were found between manual and automated compressions in: mean depth (48 ± 4 mm vs. 56 ± 3 mm, p < 0.0001), mean rate (117 ± 9 mm vs. 103 ± 1 mm, p < 0.0001), percentage of CC with correct depth (46 ± 25 vs. 87 ± 13, p < 0.0001), rate (72 ± 22 vs. 96 ± 4, p < 0.0001), and recoil (55 ± 23 vs. 89 ± 13, p < 0.0001). CCF was also higher when the ACCD was used (74 ± 7% vs. 83 ± 2%, p < 0.0001). CONCLUSIONS: The use of an ACCD increases the quality of compressions by improving CCF, chest recoil, and the percentage of compressions performed with adherence to guidelines.

Assessment of Chest Compression Quality — a systematic review

INTRODUCTION: High-quality chest compression (CC) is a crucial factor that determines the survival of cardiac arrest patients. Adequate quality should be featured by appropriate compression rate and depth, and full chest recoil after each compression. The ranges are strictly determined in Resuscitation Guidelines. All these parameters are interdependent. Currently, there is a need to find or develop a universal index that will enable the definition and determination of the overall quality of CCs. MATERIAL AND METHODS: A systematic review of the MEDLINE, EMBASE, COCHRANE, and GOOGLE SCHOLAR databases was performed. The authors aimed to find papers in which the quality of CC was assessed. The extracted information included measurement of the CC quality in a direct and objective manner — by analysing the depth, rate, and recoil of CC, position of the hands, duty cycle, and indirectly by evaluating chest compression fraction (CCF). Papers describing the quality of CC based on a combination of various components of the CC quality were selected for analysis. RESULTS: In total 1604 publications were obtained. Among them, 21 articles satisfied the search criteria. In most of the papers, it was suggested that compressions should have been considered as correct when they met simultaneously all quality criteria. Only three papers presented any mathematical formula that could have been used for further comparisons. CONCLUSIONS: Although many proposals have been developed, no single, universal, and commonly accepted indicator of resuscitation quality has been so far designed and subsequently applied. Further work on this subject is warranted and strongly recommended.

Comparing Real-Time Feedback Modalities to Support Optimal Cardiopulmonary Resuscitation for Undergraduate Nursing Students: A Quasi-Experimental Cross-Over Simulation Study

BackgroundOptimal cardiopulmonary resuscitation (CPR) is reliant on a chain of well performed interventions and skills. To investigate whether CPR feedback devices improve performance for nursing students, the effects of three feedback modalities—visual: Laerdal SimPad®; visual-embodied metaphoric: Innosonian Brayden Pro®; and visual-audio: Physio-Control TrueCPR®—was tested. MethodA quasi-experimental cross-over study compared performance metrics of participant exposure to three feedback modalities and standard adult basic life support (BLS) without feedback in a simulated environment. After baseline training, 64 participants performed adult single-rescuer BLS on a manikin for each modality and without feedback for two minutes. Effective chest compressions (correct depth, thoracic recoil, pressure point, rate, no-flow fraction) and ventilation parameters were compared using Friedman and Wilcoxon tests. ResultsSuperior technical accuracy in CPR skills performance was evident with all feedback modalities when compared with no feedback p = <.05); visual-audio feedback (TrueCPR®) was most effective (p = .005). Participants demonstrated higher technical accuracy in CPR performance (30:2 cycles; chest compression number/rate/depth; chest recoil; pressure point; correct number of ventilations) when compared with no feedback (p = .0001), despite achieving national certification three weeks before data collection. ConclusionThis appears to be the first study to explore the use of feedback modalities during CPR performance in nursing students. These feedback devices can play a major role in improving measurable parameters of BLS and psychomotor skill capability. Modalities varied in their ability to improve performance; visual-audio feedback significantly improved chest compressions, ventilation and cycle performance, whereas visual-graph–based feedback improved flow fraction and ventilations.

Evaluation of a Multimodal Resuscitation Program and Comparison of Mouth-to-Mouth and Bag-Mask Ventilation by Relatives of Children With Chronic Diseases.

Children with chronic critical illness are at higher risk for cardiopulmonary arrests. Before chronically ill children are discharged from hospital, family members receive training in basic life support at many institutions. We evaluated whether a multimodal training program is able to teach adherence to current resuscitation guidelines and whether laypersons can be trained to perform both bag-mask ventilation and mouth-to-mouth ventilation equally effective in infants. Prospective observational study. Pediatric critical care unit of a tertiary referral center. Relatives of children with chronic illness prior to discharge from hospital. Multimodal emergency and cardiopulmonary resuscitation training program. Following participation in our cardiopulmonary resuscitation training program 56 participants performed 112 simulated cardiopulmonary resuscitations (56 with mouth-to-mouth ventilation, 56 with bag-mask ventilation). Nearly all participants checked for consciousness and breathing. Shouting for help and activation of the emergency response system was only performed in half of the cases. There was almost full adherence to the resuscitation guidelines regarding number of chest compressions, chest compression rate, compression depth, full chest recoil, and duration of interruption of chest compression for rescue breaths. The comparison of mouth-to-mouth ventilation and bag-mask ventilation revealed no significant differences regarding the rate of successful ventilation (mouth-to-mouth ventilation: 77.1% ± 39.6%, bag-mask ventilation: 80.4% ± 38.0%; p = 0.39) and the cardiopulmonary resuscitation performance. A standardized multimodal cardiopulmonary resuscitation training program for family members of chronically ill children is effective to teach good cardiopulmonary resuscitation performance and adherence to resuscitation guidelines. Laypersons could be successfully trained to equally perform mouth-to-mouth and bag-mask ventilation technique.

The effect of chest compression frequency on the quality of resuscitation by lifeguards. A prospective randomized crossover multicenter simulation trial.

The ability to perform high-quality cardiopulmonary resuscitation is one of the basic skills for lifeguards. The aim of the study was to assess the influence of chest compression frequency on the quality of the parameters of chest compressions performed by lifeguards. This prospective observational, randomized, crossover simulation study was performed with 40 lifeguards working in Warsaw, Wroclaw, and Poznan, Poland. The subjects then participated in a target study, in which they were asked to perform 2-min cycles of metronome-guided chest compressions at different rates: 80, 90, 100, 110, 120, 130, 140, and 150 compressions per minute (CPM). The study involved 40 lifeguards. Optimal chest compression score calculated by manikin software was achieved for 110-120 CPM. Chest compression depth achieved 53 (interquartile range [IQR] 52-54) mm, 56 (IQR 54-57) mm, 52.5 (IQR 50-54) mm, 53 (IQR 52-53) mm, 50 (IQR 49-51) mm, 47 (IQR 44-51) mm, 41 (IQR 40-42) mm, 38 (IQR 38-43) mm for 80, 90, 100, 110, 120, 130, 140 and 150 CPM, respectively. The percentage of chest compressions with the correct depth was lower for rates exceeding 120 CPM. The rate of 100-120 CPM, as recommended by international guidelines, is the optimal chest compression rate for cardiopulmonary resuscitation performed by lifeguards. A rate above 120 CPM was associated with a dramatic decrease in chest compression depth and overall chest compression quality. The role of full chest recoil should be emphasized in basic life support training.

Advantage and Limitation of Using a Visual Feedback Device during Cardiopulmonary Resuscitation Training.

Recent cardiopulmonary resuscitation (CPR) guidelines recommend the use of CPR prompt/feedback devices during CPR training because it can improve the quality of CPR. Chest compression depth and full chest recoil show a trade-off relationship. Therefore, achievement of both targets (adequate chest compression depth and full chest recoil) simultaneously is a difficult task for CPR instructors. This study hypothesized that introducing a visual feedback device to the CPR training could improve the chest compression depth and ratio of full chest recoil simultaneously. The study investigated the effects of introducing a visual feedback device during CPR training by comparing the results of skill tests before and after introducing a visual feedback device. The results of skill tests from 2016 through 2018 were retrospectively reviewed. The strategy of emphasizing chest compression depth was implemented during the CPR training in 2017, and a visual feedback device was introduced in 2018. The interval between the CPR training and skill tests was seven days. Feedback was not provided during the skill tests. In total, 159 students completed skill tests. Although the chest compression depth increased significantly from 50 mm (42-54) to 60 mm (59-61) after emphasizing chest compression depth (P < .001), the ratio of full chest recoil decreased simultaneously from 100% (100-100) to 81% (39-98; P < .001). The ratio of full chest recoil increased significantly from 81% (39-98) to 95% (77-100) after introducing a visual feedback device (P = .018). However, the students who did not achieve 80% of the ratio of full chest recoil remained significantly higher than in 2016 (1% in 2016, 49% in 2017, and 27% in 2018; P < .001). Although introducing a visual feedback device during CPR training resulted in increasing the ratio of full chest recoil while maintaining the adequacy of chest compression depth, 27% of the students still did not achieve 80% of the ratio of full chest recoil. Another educational strategy should be considered to increase the qualities of CPR more completely.

Accuracy of Healthcare Providers' Perception of Chest Compression Depth and Chest Recoil

Objective: The objective of this paper was to evaluate the validity and accuracy of healthcare providers’ perception of chest compression depth and chest recoil during cardiopulmonary resuscitation (CPR). Methods: A clinical simulation study was performed with healthcare providers trained in CPR including physicians, nurses, and Emergency Medical Technicians (EMT). Following 2 minutes of hands-only-CPR on a sensor-programmed manikin, providers were able to respond to subjective questions assessing their adequacy of CPR. The providers’ perception contrasted with the objective data obtained from the manikin. The validity and accuracy of CPR providers’ perception of chest compression depth and chest recoil was assessed by the calculation of sensitivity, specificity and predictive values. Results: 180 Advanced or basic life support certified healthcare providers were enrolled. The degree of correlation between self-perception and actual performance was 52.2% in the thoracic compression depth and 61.7% in the chest recoil. Caregivers’ perception of chest compression depth had a sensitivity of 29.4% and a specificity of 87.3%. Caregivers’ perception of chest recoil had a sensitivity of 30.3% and a specificity of 79.8%. Conclusions: Healthcare providers’ perception for evaluating the accuracy of thoracic compressions is not as accurate as objective feedback methods during CPR. This may impact patient outcomes during a cardiac arrest.

Quality of Chest Compressions on A Dental Chair -- A Randomized Simulation Trial as Observation in Support of A Procedure Proposal

Background: Although medical emergencies among dental patients are not frequent, several factors may provoke sudden cardiac arrests. Early initiation of high-quality chest compressions (CC) is of crucial importance for the safety and effectiveness of cardiopulmonary resuscitation (CPR). Aims: We aimed to evaluate the quality of chest compressions performed on a dental chair for the proposed procedure in case of cardiac arrest in a dental office. Methods: We designed a prospective, randomized, crossover simulation study. Sixty paramedic students were randomly assigned to the control group, in which resuscitation was performed on the floor (n = 30) or to the experimental group, in which compressions were performed on a dental unit (n = 30). We used a simulator that recorded number of compressions, rate, depth of compressions and chest recoil. Results: There were no significant differences in numbers, rate, depth of chest compressions or in chest recoil between groups. Conclusions: We proved that performing chest compressions on a dental chair might be as effective as on the floor. On this basis, we propose a procedure for safe and efficient performance of CPR in a dental office.

Is Mouth-to-mouth Ventilation Effective in Lifeguards?Comparing the Effects between 30:2 Algorithm Versus Hands-only. A Simulation Study

Aim: Compare which resuscitation (for cardiac arrest scenario) has a higher quality when first responders with a duty of care are deprived of material: a standard resuscitation algorithm or a hands-only one when performed by lifeguards, who have had extensive training on mouth-to-mouth ventilation. Besides, a more specific objective was the analysis of the characteristics of these mouth-to-mouth ventilation. Methods: We conducted a prospective quasi-experimental crossover manikin study with clinical simulation with 41 lifeguards attached to the Plan of Surveillance and Rescue in Beaches. Each participant performed 2 minutes of basic life support (CPRb). Afterward, each participant performed 2 minutes of CPR with hands-only (CPRho). The data collection was carried out with a CPR calibrated Mannequin. Results: The mean depth was 48.05± 8.99 mm for CPRb, and 44.76 ± 9.73 mm for CPRho (t = 5.81, p &lt; 0.001, 95% CI, 2.15 - 4.44), the rate was 123 ± 16.11 compressions/min for CPRb and 120 ± 17.89 for CPRho. The CPRho achieved a mean of 46 ± 42.6 complete chest recoil, versus 35 ± 35.19 for CPRb (z = -2.625, p = 0.009). 20.74% of ventilation were hypoventilation and 42.72% were hyperventilation. Conclusions: Mouth-to-mouth ventilation performed by lifeguards (without devices) was not effective. When ventilations were not performed, the number of high-quality compressions increased in absolute values. The mean depth of chest compressions was higher in the CPRho. Most of the participants did not perform the ventilations correctly, which resulted in time without compression and ventilation. The number of chest compressions with complete chest recoil was higher in CPRho. When ventilations were not performed, the number of high-quality compressions increased in absolute values.

The changes in cardiopulmonary resuscitation guidelines: from 2000 to the present.

This review aims to determine the changes made in the cardiopulmonary resuscitation (CPR) guidelines from 2000 to the present. The study was mainly undertaken by using International Guidelines from American Heart Association. The main change of CPR was chest compression skill. The guidelines have improved high-quality CPR through the change of chest compression skill. The latest adult CPR guidelines are as follows: (a) push chest quickly (100–120/min), (b) compress appropriately (5–6 cm), (c) relax chest fully (complete chest recoil), (d) avoid interruption of compression, and (e) avoid hyperventilation. The understanding of the latest CPR skills will be helpful in improving survival rate from sudden cardiac death.

Real-Time Audiovisual Feedback Training Improves Cardiopulmonary Resuscitation Performance: A Controlled Study.

The aim of the study was to quantitatively measure the effect of teaching cardiopulmonary resuscitation (CPR) using a real-time audiovisual feedback manikin system on first-year medical student's CPR performance. This is a prospective, manikin-based intervention study, including 2 consecutive classes of medical school students enlisted to a mandatory first aid course. One class (control group) was taught using manikin-based standard CPR education models. The second class (intervention group) was taught similarly, but with the addition of real-time CPR quality feedback provided by the manikins. Students' performance was assessed using a standardized Objective Structured Clinical Examination scenario, during which no real-time feedback was provided. Critical CPR parameters were measured including compression depth, chest recoil, ventilation volume, and "hands-off" time. A total of 201 participants were included in the study, 106 in the control group and 95 in the intervention group. Baseline demographic characteristics and previous medical knowledge were similar for the 2 groups. A significant improvement was observed for all primary study outcomes in favor of the real-time feedback group for median (interquartile range) chest compression fraction [57 (52.75%-60%) vs. 49 (43%-55%), P < 0.001], compressions with adequate depth [66.5 (19.5%-95.25%) vs. 0 (0%-12%), P < 0.001], ventilations with adequate volume [68.5 (33%-89%) vs. 37 (0%-70%), P < 0.00], and a simulator-derived composite "total CPR score" [39 (24%-61.25%) vs. 13 (3.5%-22%), P < 0.001]. In multiple regression analysis, the real-time feedback group's performance was significantly better than the control group in all primary outcomes, adjusting for participant's characteristics of age, sex, and body mass index. The use of audiovisual feedback techniques to teach CPR improves skill acquisition with significant improvement in crucial prognosis-improving parameters, as tested in a "no-feedback" test scenario.

Abstract 396: Successful Virtual Reality Cardiopulmonary Resuscitation Training in Schools: Digitally Linking a Physical Manikin to a Virtual Lifesaving Scenario

Introduction: The AHA trains over 20 million people in CPR skills annually. Virtual Reality (VR) education may improve student engagement, but the efficacy of VR-CPR programs has not been adequately studied. We performed the largest study to-date evaluating the feasibility of VR-enhanced CPR training. Hypothesis: We hypothesized that an immersive, VR-enhanced CPR training program, digitally linked to a physical manikin, can teach middle/high-school students Hands-Only CPR skills resulting in strong learner engagement. Methods: We linked a VR-enhanced CPR training program to a standard manikin with an optical “time of flight” sensor and hand-tracking gloves. Based on AHA’s Hands-Only CPR protocol, training included compression rate (100-120/min), depth (2-2.4”), hand position, and full chest recoil, with 124 students from 3 middle/high-schools in Florida (n= 38) and California (n=42, n=44). Iterations to streamline the user experience were implemented for Pilots 2 and 3. Results: VR-enhanced CPR training significantly improved compression rate, depth, and hand position; chest recoil was not statistically changed. Post-training, students were tested on CPR knowledge: 78% (96/124) were correct on nature of cardiac arrest, 88% (109/124) on compression rate, and 83% (103/124) on compression depth. Of students with prior CPR training, 79% stated VR-CPR training was more effective than prior training. Iterations in Pilots 2 and 3 were associated with additional learning gains at those sites. Conclusions: In this first-of-its-kind study, middle/high school students learned Hands-Only CPR skills and knowledge with a VR-enhanced CPR training program digitally linked to a physical manikin. Our VR-CPR training uniquely separates each of 4 Hands-Only CPR skills into separate training modules in which students receive instant feedback. Future study and development of VR-CPR is warranted, especially as learning gains were associated with user experience iterations.

Abstract 296: Quality Analysis of Cardiopulmonary Resuscitation From Two Emergency Medical Service Systems Using a Feedback Device

Background: High quality cardiopulmonary resuscitation (CPR) plays a critical role in the success of out-of-hospital resuscitation from sudden cardiac arrest (SCA). AHA guidelines provide protocol to achieve recommended targets for CPR quality metrics including chest compression fraction (CCF), percentage of chest compressions (CCs) with full chest recoil, CC rate and CC depth. Our objective was to report the CPR quality of two emergency medical services (EMS) agencies with different basic life support (BLS) CPR protocols. Methods: Data from 673 patients, 2015 to 2017, suffering out-of-hospital SCA were obtained from Philips FR3 AEDs. The Philips Q-CPR tool was used for real-time CPR feedback, and CC waveforms were recorded for retrospective CPR analysis using Philips Event Review Pro 5.0 and custom software. The two EMS systems had BLS protocol differences: Site 1(King County, WA, n = 93) applied a compression - ventilation ratio of 30:2, while Site 2 (Mecklenburg County, NC, n = 580) applied 200 compressions in each CPR interval and ventilations were performed during CCs. Analyses were performed comparing CPR metrics between sites and to AHA targets. Results: There were 3,460 minutes of resuscitation data analyzed, representing the initial phase of resuscitation prior to ALS. The proportion of cases with shocks was 21.5% (20 of 93) for site 1 and 16.9% (98 of 580) for site 2 (p = 0.3). Both sites achieved guideline metrics though there were statistical differences (Table 1). Compared to site 1, site 2 was associated with a higher CCF, faster CC rate, but less CC depth on average (p &lt; 0.001). Conclusions: High quality CPR defined by AHA guidelines was achieved with both sites during the early phase of AED resuscitation though some differences were observed. Additional investigation should identify equipment, or rescuer characteristics that are important to consistently achieve high quality CPR and how the combination might be tailored to optimize individual patient outcome.

Abstract 240: Smartphone Application to Provide Real-Time Cardiopulmonary Resuscitation Quality Feedback

Introduction: Quality of cardiopulmonary resuscitation (CPR) contributes significantly to morbidity and mortality in both in-hospital and out-of-hospital cardiac arrest. Key parameters that determine the CPR quality are compression rate, compression depth, duration of interruptions, chest recoil factor and respiratory rate. Several studies have demonstrated that real-time audiovisual feedback improves CPR quality in both bystanders and hospital staff. This study aims to develop and validate a smart device (phones and wearable technology) application to provide real-time audiovisual and haptic feedback to optimize CPR quality, by calculating aforementioned chest compression parameters. Hypothesis: A mobile application using acceleration sensor data from smart devices can provide accurate real time CPR quality feedback. Methods: A mobile application was developed to track the compression depth, compression rate and pause duration in real time using the data captured from the on-device accelerometer. The mobile device was placed on an adult manikin’s chest along the midline close to the point of compressions. Data from the application was compared directly to data obtained from a validated clinical standard CPR quality tool. Results: CPR quality parameters were obtained from the app and the standard for 60, 10-second-long sessions. Bland-Altman plot analysis for compression depth showed agreement between the app measurements and standard within +/-3.5mm (Figure 1). The intraclass correlation for agreement in the measurement of compression count was 0.92 (95% CI: 0.88-0.95), indicative of very strong agreement. Conclusions: Smart device (phones and wearable technology) applications using acceleration sensor data can accurately provide real-time CPR quality feedback. With further development and validation they can provide a ubiquitous CPR feedback tool valuable for out of hospital arrests and in under-privileged areas worldwide.

Abstract 255: A Novel and Accurate Method for Assessing Recoil During CPR Training

Introduction: In addition to accurate measurement depth and rate of each compression, accurate measurement of full recoil, after each compression, is mandatory for the CPR training. Permitting complete chest recoil during the decompression phase of CPR is essential for refilling the lungs and for adequate myocardial perfusion. Complete chest recoil is important but not evaluated during CPR training. Currently, the recoil is measured based on the residual force when the rescuer releases the hands. Recent clinical research shows the recoil measurements need to consider the release time, release velocity and release height. Hypothesis: With a commercially available smartphone providing real-time feedback (placed on an armband of the subjects), trainees will improve recoil performance using proper release velocity, release time and release height. Methods: Using a previously validated smartphone application utilizing the smartphone’s accelerometer, gyroscope and magnetometer, we measured these 3 variables. Total of ten sessions was recorded. Each individual CPR session was recorded in the application (acceleration streams, detected pumps with annotations, and the generated feedback). Audio and visual feedback was provided about the measured depth, rate, and recoil quality. Each session has 30 CPR pumps. The scripted patterns consisted of alternating (recoil on and off) window lengths of either 5 or 10 pumps, and the patterns varied between sessions. Recoil was considered to be good if releases velocity is &gt;= 400mm/sec and release time is &lt;=120ms and release height is &gt;= 2 inches. Results: Using the output of a bayesNet classifier on the manually-annotated dataset, 84% true positives (success) was achieved for all the three metrics. Conclusions: With guided feedback recoil efficiency improved.