Higher Chest Compression Fraction Research Articles

Abstract Su205: Using Emergency Medical Services Monitors for Cardiac Arrest Patients in the Emergency Department is Associated with Faster Initial Rhythm Analysis and Defibrillation

Introduction: The 2020 American Heart Association guidelines for Cardiopulmonary Resuscitation (CPR) emphasizes the importance of high-quality CPR and early defibrillation in improving cardiac arrest (CA) survival. Using our emergency department (ED) CA video review registry, we can capture metrics to reliably assess the effectiveness of different approaches to CA management. Goals/Hypothesis: We propose that emergency medical services (EMS) pads and defibrillators should be used to initially analyze cardiac rhythm in the ED. We hypothesize that this “EMS Equipment” approach is associated with shorter time to first ED rhythm detection and defibrillation, higher chest compression fraction (CCF), and improved return of spontaneous circulation (ROSC) rates. Methods: This is a single center, retrospective cohort study using our CA video review registry between 10/03/2018 – 2/20/2024. Atraumatic, out-of-hospital CA patients ≥18 years were included while patients arriving to the ED with ROSC were excluded. The “EMS Equipment” group utilized EMS pads and defibrillators while the “ED Equipment” group utilized ED pads and defibrillators for the first ED rhythm analysis. Wilcoxon rank sum tests were used to assess differences in time to first rhythm check and first defibrillation among the two groups. Chi-square tests were used to assess whether the proportions of patients achieving above median CCF, ROSC, survival to admission and discharge in the two groups were different. Results: A total of 247 patients were included in the analysis with 69 patients in the EMS Equipment group (27.9%) and 178 patients in the ED Equipment group (72.1%). The EMS Equipment group had a shorter median time to first ED rhythm detection (96 vs. 255 seconds, p <0.00001). Among the 63 patients defibrillated in the ED, the EMS Equipment group had a shorter median time to first ED defibrillation (103 vs. 413 seconds, p = 0.0024). There was no significant difference in CCF, ROSC rates, survival to admission or discharge. ROSC was achieved in 36% of cases. Conclusion: In conclusion, initial rhythm analysis with EMS pads and defibrillators was associated with shorter time to initial ED rhythm detection and defibrillation, but not improved CCF, ROSC rates, and survival. Larger studies are needed to verify these exploratory results in more diverse settings.

Abstract Su402: Comprehensive Assessment of Chest Compression Quality Across All Phases of Prehospital Care Using a Manikin

Background: High-quality cardiopulmonary resuscitation (CPR) is crucial for improving the prognosis of out-of-hospital cardiac arrest (OHCA) patients. The quality of chest compressions may vary during different phases of prehospital care. Objectives: To investigate changes in chest compression quality during prehospital activities and identify the causes. Methods: Eleven emergency medical teams of three members each participated. Using a manikin (Laerdal QCPR), we measured achievement rates of compression depth (≥5 cm) and recoil, compression rate, and chest compression fraction (CCF). The process from the scene to the hospital bed was divided into four phases: 1) on-site, 2) transport from the scene to the ambulance (canvas stretcher), 3) in the ambulance, 4) transport from the ambulance to the hospital bed (wheeled stretcher). We analyzed the quality changes in chest compressions and the causes of degradation or interruptions. Each team performed both manual CPR (Man-CPR) and mechanical CPR (Mech-CPR) using the LUCAS3 device. The scenario assumed cardiac arrest on the second floor, transport down stairs to the ambulance, and a 15-minute drive to the hospital. ACLS was established in Phase 1 and continued until hospital arrival. In Mech-CPR, a mechanical CPR device was applied in Phase 1 and used throughout all phases. Results: Man-CPR showed lower compression depth achievement in Phases 2 and 4 compared to Phases 1 and 3, mainly due to transport transitions (Fig. 1). CCF was high in Phases 1 and 3 but decreased in Phases 2 and 4 due to these transitions. Interruptions in Phases 1 and 3 were due to checking ECG rhythm, securing an airway, and confirming ventilation. Recoil achievement was low across all phases. Mech-CPR showed high achievement rates for compression depth and recoil across all phases and maintained high CCF. However, Man-CPR had a higher CCF in Phase 1 than Mech-CPR due to interruptions for device application. Mech-CPR had no degradation due to dual work, but improper application caused long degradations and interruptions. The longest interruption times were 69 seconds (transport) for Man-CPR and 25 seconds (device application) for Mech-CPR. Both Man-CPR and Mech-CPR maintained compression rates within the guideline range of 100-120/min, with Man-CPR tending to be faster. Conclusion: Chest compression quality varies from the scene to hospital arrival. Man-CPR and Mech-CPR have different causes of quality changes and interruptions.

450 A Video Review-Based Clinical Assessment Tool of Cardiac Arrest Resuscitation Correlates With Higher Chest Compression Fraction

450 A Video Review-Based Clinical Assessment Tool of Cardiac Arrest Resuscitation Correlates With Higher Chest Compression Fraction

Analysis during chest compressions in out-of-hospital cardiac arrest patients, a cross/sectional study: The DEFI 2022 study

AimsDuring out-of-hospital cardiac arrest (OHCA), an automatic external defibrillator (AED) analyzes the cardiac rhythm every two minutes; however, 80% of refibrillations occur within the first minute post-shock. We have implemented an algorithm for Analyzing cardiac rhythm While performing chest Compression (AWC). When AWC detects a shockable rhythm, it shortens the time between analyses to one minute. We investigated the effect of AWC on cardiopulmonary resuscitation quality. MethodIn this cross-sectional study, we compared patients treated in 2022 with AWC, to a historical cohort from 2017. Inclusion criteria were OHCA patients with a shockable rhythm at the first analysis. Primary endpoint was the chest compression fraction (CCF). Secondary endpoints were cardiac rhythm evolution and survival, including survival analysis of non-prespecified subgroups. ResultsIn 2017 and 2022, 355 and 377 OHCAs met the inclusion criteria, from which we analyzed the 285 first consecutive cases in each cohort. CCF increased in 2022 compared to 2017 (77% [72–80] vs 72% [67–76]; P < 0.001) and VF recurrences were shocked more promptly (53 s [32–69] vs 117 s [90–132]). Survival did not differ between 2017 and 2022 (adjusted hazard-ratio 0.96 [95% CI, 0.78–1.18]), but was higher in 2022 within the sub-group of OHCAs that occurred in a public place and within a short time from call to AED switch-on (adjusted hazard ratio 0.85[0.76–0.96]). ConclusionsOHCA patients treated with AWC had higher CCF, shorter time spent in ventricular fibrillation, but no survival difference, except for OHCA that occurred in public places with short intervention time.

The association of recent simulation training and clinical experience of team leaders with cardiopulmonary resuscitation quality during in-hospital cardiac arrest

ObjectiveWe aimed to investigate the association of recent team leader simulation training (<6 months) and years of clinical experience (≥4 years) with chest compression quality during in-hospital cardiac arrest (IHCA). MethodsThis cohort study of IHCA in four Danish hospitals included cases with data on chest compression quality and team leader characteristics. We assessed the impact of recent simulation training and experienced team leaders on longest chest compression pause duration (primary outcome), chest compression fraction (CCF), and chest compression rates within guideline recommendations using mixed effects models. ResultsOf 157 included resuscitation attempts, 45% had a team leader who recently participated in simulation training and 66% had an experienced team leader. The median team leader experience was 7 years [Q1; Q3: 4; 11]. The median duration of the longest chest compression pause was 16 s [10; 30]. Having a team leader with recent simulation training was associated with significantly shorter longest pause durations (difference: −7.11 s (95%-CI: −12.0; −2.2), p = 0.004), a higher CCF (difference: 3% (95%-CI: 2.0; 4.0%), p < 0.001) and with less guideline compliant chest compression rates (odds ratio: 0.4 (95%-CI: 0.19; 0.84), p = 0.02). Having an experienced team leader was not associated with longest pause duration (difference: −1.57 s (95%-CI: −5.34; 2.21), p = 0.42), CCF (difference: 0.7% (95%-CI: −0.3; 1.7), p = 0.17) or chest compression rates within guideline recommendations (odds ratio: 1.55 (95%-CI: 0.91; 2.66), p = 0.11). ConclusionRecent simulation training of team leaders, but not years of team leader experience, was associated with shorter chest compression pauses during IHCA.

Who is the real team leader? Comparing leadership performance of the team leader and CPR Coach during simulated cardiac arrest

PurposeTo describe the leadership performance of team leaders and CPR Coaches, and to determine if there is a correlation between leadership scores and CPR performance during management of simulated pediatric cardiac arrest events. MethodsThis is a secondary analysis of data from a prior randomized controlled trial. We observed the performance of both team leaders and CPR coaches during the management of an 18-minute simulated cardiac arrest scenario which was run for 20 resuscitation teams comprised of CPR-certified professionals from four pediatric tertiary care centers. CPR Coaches were responsible for providing real-time verbal feedback of CPR performance to compressors. Two raters were trained to use the Behavioral Assessment Tool (BAT) to assess leadership performance of the team leader and CPR Coach. BAT scores of team leaders and CPR coaches were compared and linked with objective CPR performance. ResultsThere was no significant difference between the BAT scores of team leaders and CPR coaches (median score 27/40 vs 28.8/40, p = 0.16). Higher BAT scores of team leaders were significantly associated with higher percentage of excellent CPR (r = 0.52, p = 0.02), while higher BAT scores of CPR coaches were significantly associated with higher chest compression fraction (r = 0.48, p = 0.03). ConclusionsBoth team leaders and CPR coaches have similarly high leadership performance during the management of simulated cardiac arrest. Leadership behaviors were associated with quality of CPR performance.Clinical Trial Registration: Registration ID: NCT02539238; https://www.clinicaltrials.gov.

Shoulder strap fixation of LUCAS-2 to facilitate continuous CPR during non-supine (stair) stretcher transport of OHCAs patients

Early recognition and rapid initiation of high-quality cardiopulmonary resuscitation (CPR) are key to maximising chances of achieving successful return of spontaneous circulation in patients with out-of-hospital cardiac arrests (OHCAs), as well as improving patient outcomes both inside and outside hospital. Mechanical chest compression devices such as the LUCAS-2 have been developed to assist rescuers in providing consistent, high-quality compressions, even during transportation. However, providing uninterrupted and effective compressions with LUCAS-2 during transportation down stairwells and in tight spaces in a non-supine position is relatively impossible. In this study, we proposed adaptations to the LUCAS-2 to allow its use during transportation down stairwells and examined its effectiveness in providing high-quality CPR to simulated OHCA patients. 20 volunteer emergency medical technicians were randomised into 10 pairs, each undergoing 2 simulation runs per experimental arm (LUCAS-2 versus control) with a loaded Resusci Anne First Aid full body manikin weighing 60 kg. Quality of CPR compressions performed was measured using the CPRmeter placed on the sternum of the manikin. The respective times taken for each phase of the simulation protocol were recorded. Fisher’s exact tests were used to analyse categorical variables and median test to analyse continuous variables. The LUCAS-2 group required a longer time (~ 35 s) to prepare the patient prior to transport (p < 0.0001) and arrive at the ambulance (p < 0.0001) compared to the control group. The CPR quality in terms of depth and rate for the overall resuscitation period did not differ significantly between the LUCAS-2 group and control group, though there was a reduction in both parameters when evaluating the device’s automated compressions during transport. Nevertheless, the application of the LUCAS-2 device yielded a significantly higher chest compression fraction of 0.76 (p < 0.0001). Our novel adaptations to the LUCAS-2 device allow for uninterrupted compressions in patients being transported down stairwells, thus yielding better chest compression fractions for the overall resuscitation period. Whether potentially improved post-OHCA survival rates may be achieved requires confirmation in a real-world scenario study.

The impact of increased chest compression fraction on survival for out-of-hospital cardiac arrest patients with a non-shockable initial rhythm

ObjectiveWe evaluated the effect of chest compression fraction (CCF) on survival to hospital discharge and return of spontaneous circulation (ROSC) in out-of-hospital cardiac arrest (OHCA) patients with non-shockable rhythms. MethodsThis is a retrospective analysis (completed in 2016) of a prospective cohort study which included OHCA patients from ten U.S. and Canadian sites (Resuscitation Outcomes Consortium Epistry and PRIMED study (2007–2011)). We included all OHCA victims of presumed cardiac aetiology, not witnessed by emergency medical services (EMS), without automated external defibrillator shock prior to EMS arrival, receiving > 1 min of CPR with CPR process measures available, and initial non-shockable rhythm. We measured CCF using the first 5 min of electronic CPR records. ResultsDemographics of 12,928 adult patients were: mean age 68; male 59.9%; public location 8.5%; bystander witnessed 35.2%; bystander CPR 39.3%; median interval from 911 to defibrillator turned on 10 min:04 s; initial rhythm asystole 64.8%, PEA 26.0%, other non-shockable 9.2%; compression rate 80−120/min (69.1%); median CCF 74%; ROSC 25.6%; survival to hospital discharge 2.4%. Adjusted odds ratio (OR); 95% confidence intervals (95%CI) of survival for each CCF category were: 0−40% (2.00; 1.16, 3.32); 41−60% (0.83; 0.54, 1.24); 61−80% (1.02; 0.77, 1.35); and 81−100% (reference group). Adjusted (OR; 95%CI) of ROSC for each CCF category were: 0−40% (1.02; 0.79, 1.30); 41−60% (0.83; 0.72, 0.95); 61−80% (0.85; 0.77, 0.94); and 81−100% (reference group). ConclusionsWe observed an incremental benefit from higher CCF on the incidence of ROSC, but not survival, among non-shockable OHCA patients with CCF higher than 40%.

Abstract 32: Chest Compression Fraction Increased When Police Used AED That Analyses Heart Rhythm During CPR

Introduction: Conventional automated external defibrillators (AED) prompt rescuers to stop cardiopulmonary resuscitation (CPR) for ECG analysis during cardiac arrest (CA), but pauses in CPR are associated with worse outcome. A new AED algorithm, cprINSIGHT™ Analysis Technology, analyses the ECG while rescuers continue chest compressions. Hypothesis: Compared to conventional AEDs, AEDs with the cprINSIGHT algorithm will lead to fewer and shorter interruptions of chest compressions for ECG analysis and, thereby, a higher chest compression fraction (CCF). Methods: Amsterdam Police used conventional AEDs in 2016 (LIFEPAK® 1000 defibrillator) and AEDs with cprINSIGHT in 2018 (LIFEPAK CR2 AED); in the CR2 AED, cprINSIGHT is activated after the first conventional analysis. We analysed AED data from control CA cases in 2016 and intervention CA cases in 2018, comparing pre-shock pause, median CCF and CCF categories. CCF was defined as the proportion of time with chest compressions in the period from the start of CPR after analysis 1 to the start of CPR after analysis 2. The CCF analysis included only cases where CPR was provided with a ratio of 30 compressions to 2 ventilations. Results: Data from 111 control and 87 intervention cases were analysed. The initial recorded rhythm was shockable in 42 control cases (38%) and 36 intervention cases (41%). Rhythm during analysis 2 was shockable in 28/103 (27%) control and 19/80 (24%) intervention cases; 15 cases had no second analysis. In 67/80 (84%) intervention cases, analysis 2 reached a decision without prompting for a CPR pause. Intervention cases had a significantly shorter pre-shock pause than control cases (7 sec vs 22 sec, p &lt; 0.001) and significantly higher median CCF (87% vs 77%, P&lt;0.001). CCF was ≥90% in 38% of intervention cases and 10% of control cases (figure). Conclusion: The use of the cprINSIGHT algorithm in AEDs leads to a shorter pre-shock pause, fewer analysis pauses and an increase in CCF compared to conventional AEDs.

Abstract 20: Peripheral Intravenous Analysis Detects Return of Spontaneous Circulation Without Interruption of Chest Compressions in a Rat Model of Cardiopulmonary Resuscitation

Introduction: A higher chest compression fraction (CCF) or percentage of time providing chest compressions is associated with improved survival after cardiac arrest (CA). Pauses in chest compression duration during cardiopulmonary resuscitation (CPR) to palpate a pulse can reduce the CCF. Peripheral Intravenous Analysis (PIVA) is a novel method for determining cardiac and volume status using waveforms from a standard peripheral intravenous (IV) line. We hypothesize that PIVA will demonstrate the onset of return of spontaneous circulation (ROSC) without interruption of CPR. Methods: Eight Zucker Diabetic Fatty (ZDF) rats (4 lean, 4 diabetic) were intubated, ventilated, and cannulated with a 24g IV in the tail vein and a 22g IV in the femoral artery, each connected to a TruWave pressure transducer. Mechanical ventilation was discontinued to achieve CA. After 8 minutes, CPR began with mechanical ventilation, IV epinephrine, and chest compressions using 1.5 cm at 200 times per minute until mean arterial pressure (MAP) increased to 120 mmHg per arterial line. All waveforms were recorded and analyzed in LabChart. PIVA was measured using a Fourier transform of the peripheral venous waveform. Data are mean ± SD. Statistics: Unpaired student’s t-test (two-tailed), α = 05. Results: CA and ROSC were achieved in all 8 rats. Within 1 minute of CPR, there was a 70 ± 35 fold increase/decrease in PIVA during CPR that was temporally associated with ROSC. Within 8 ± 13 seconds of a reduction in PIVA, there was a rapid increase in end-tidal CO 2 . In all rats, ROSC occurred within 38 ± 9 seconds of the maximum PIVA value. Peripheral venous pressure decreased by 1.2 ± 0.9 mmHg during resuscitation and ROSC, which was not significant different at p=0.05. Conclusion: In this pilot study, PIVA detected ROSC without interrupting CPR. Use of PIVA may obviate the need pause CPR for pulse checks, and may result in a higher CCF and survival. Future studies will focus on PIVA and CPR efficacy.

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 33: Impact of a Mobile Application for ACLS on House Staff Performance During Cardiac Arrest Simulations

Background: Effective and timely delivery of cardiac arrest interventions during a resuscitation for in-hospital cardiac arrest (IHCA) is associated with a higher likelihood of survival. House staff play a pivotal role in leading resuscitations during IHCA. Whether a mobile application (App) that provides real-time reminders and dosing recommendations for defibrillation and vasoactive medications improves adherence to ACLS guidelines remains unknown. Methods: As part of a quality improvement initiative, internal medicine residents at Saint Luke’s Mid America Heart Institute underwent two different cardiac arrest simulations and were randomized to do one simulation with the App and one without. All simulations included 4 rhythm cycles and were video recorded to ensure accuracy in endpoint assessments. The co-primary endpoints were chest compression fraction (i.e., time doing chest compressions / total time of the simulation) and number of correct interventions (e.g., defibrillation, epinephrine or amiodarone within the correct time frame and with accurate dosing) out of 7 in each simulation. The secondary endpoint was incorrect interventions, defined as interventions not indicated by ACLS guidelines (e.g., atropine for asystole). Paired t-tests compared performance with and without the App. Results: Among 53 residents, 26 were randomized to do the first simulation with the App and 27 without the App. Use of the App was associated with a higher number of correct ACLS interventions (out of 7): mean of 6.2 vs. 5.1; absolute difference of 1.1 (95% CI: 0.6, 1.6); P&lt;0.001) as well as fewer incorrect ACLS interventions (mean of 0.3 vs. 1.0; absolute difference of -0.7 (95% CI: -0.3, -1.0); P&lt;0.001). Simulations performed with the App also had a marginally higher chest compression fraction (mean: 90.9% vs. 89.0%; absolute difference 2.0% (95% CI: 0.6%, 3.4%; P=0.007). Conclusion: Use of a mobile application by residents during simulations was associated with better adherence to ACLS performance measures. This proof-of-concept study suggests this novel mobile App may improve adherence to ACLS, but its effectiveness on survival in real-world resuscitations remains unknown.

LUCAS Versus Manual Chest Compression During AmbulanceTransport: A Hemodynamic Study in a Porcine ModelofCardiac Arrest.

BackgroundMechanical chest compression (CC) is currently suggested to deliver sustained high‐quality CC in a moving ambulance. This study compared the hemodynamic support provided by a mechanical piston device or manual CC during ambulance transport in a porcine model of cardiopulmonary resuscitation.Methods and ResultsIn a simulated urban ambulance transport, 16 pigs in cardiac arrest were randomized to 18 minutes of mechanical CC with the LUCAS (n=8) or manual CC (n=8). ECG, arterial and right atrial pressure, together with end‐tidal CO2 and transthoracic impedance curve were continuously recorded. Arterial lactate was assessed during cardiopulmonary resuscitation and after resuscitation. During the initial 3 minutes of cardiopulmonary resuscitation, the ambulance was stationary, while then proceeded along a predefined itinerary. When the ambulance was stationary, CC‐generated hemodynamics were equivalent in the 2 groups. However, during ambulance transport, arterial and coronary perfusion pressure, and end‐tidal CO2 were significantly higher with mechanical CC compared with manual CC (coronary perfusion pressure: 43±4 versus 18±4 mmHg; end‐tidal CO2: 31±2 versus 19±2 mmHg, P<0.01 at 18 minutes). During cardiopulmonary resuscitation, arterial lactate was lower with mechanical CC compared with manual CC (6.6±0.4 versus 8.2±0.5 mmol/L, P<0.01). During transport, mechanical CC showed greater constancy compared with the manual CC, as represented by a higher CC fraction and a lower transthoracic impedance curve variability (P<0.01). All animals in the mechanical CC group and 6 (75%) in the manual one were successfully resuscitated.ConclusionsThis model adds evidence in favor of the use of mechanical devices to provide ongoing high‐quality CC and tissue perfusion during ambulance transport.

Why do some studies find that CPR fraction is not a predictor of survival?

IntroductionAn 80% chest compression fraction (CCF) during resuscitation is recommended. However, heterogeneous results in CCF studies were found during the 2015 Consensus on Science (CoS), which may be because chest compressions are stopped for a wide variety of reasons including providing lifesaving care, provider distraction, fatigue, confusion, and inability to perform lifesaving skills efficiently. ObjectiveThe effect of confounding variables on CCF to predict cardiac arrest survival. MethodsA secondary analysis of emergency medical services (EMS) treated out-of-hospital cardiac arrest (OHCA) patients who received manual compressions. CCF (percent of time patients received compressions) was determined from electronic defibrillator files. Two Sample Wilcoxon Rank Sum or regression determined a statistical association between CCF and age, gender, bystander CPR, public location, witnessed arrest, shockable rhythm, resuscitation duration, study site, and number of shocks. Univariate and multivariate logistic regressions were used to determine CCF effect on survival. ResultsOf 2132 patients with manual compressions 1997 had complete data. Shockable rhythm (p<0.001), public location (p<0.004), treatment duration (p<0.001), and number of shocks (p<0.001) were associated with lower CCF. Univariate logistic regression found that CCF was inversely associated with survival (OR 0.07; 95% CI 0.01–0.36). Multivariate regression controlling for factors associated with survival and/or CCF found that increasing CCF was associated with survival (OR 6.34; 95% CI 1.02–39.5). ConclusionCCF cannot be looked at in isolation as a predictor of survival, but in the context of other resuscitation activities. When controlling for the effects of other resuscitation activities, a higher CCF is predictive of survival. This may explain the heterogeneity of findings during the CoS review.

Association Between Chest Compression Interruptions and Clinical Outcomes of Ventricular Fibrillation Out-of-Hospital Cardiac Arrest.

Minimizing pauses in chest compressions during cardiopulmonary resuscitation is a focus of current guidelines. Prior analyses found that prolonged pauses for defibrillation (perishock pauses) are associated with worse survival. We analyzed resuscitations to characterize the association between pauses for all reasons and both ventricular fibrillation termination and patient survival. In 319 patients with ventricular tachycardia/fibrillation out-of-hospital cardiac arrest, we analyzed recordings from all defibrillators used during resuscitation and measured durations of all cardiopulmonary resuscitation pauses. Median durations were 32 seconds (25th and 75th percentile, 22 and 52 seconds) for the longest pause for any reason, 23 seconds (25th and 75th percentile, 14 and 34 seconds) for the longest perishock pause, and 24 seconds (25th and 75th percentile, 11 and 38 seconds) for the longest nonshock pause. Multivariable regression models showed lower odds for survival per 5-second increase in the longest overall pause (odds ratio, 0.89; 95% confidence interval, 0.83-0.95), longest perishock pause (odds ratio, 0.85; 95% confidence interval, 0.77-0.93), and longest nonshock pause (odds ratio, 0.83; 95% confidence interval, 0.75-0.91). In 36% of cases, the longest pause was a nonshock pause; this subgroup had lower survival than the group in whom the longest pause was a perishock pause (27% versus 44%, respectively; P<0.01) despite a higher chest compression fraction. Preshock pauses were 8 seconds (25th and 75th percentile, 4 and 17 seconds) for shocks that terminated ventricular fibrillation and 7 seconds (25th and 75th percentile, 4 and 13 seconds) for shocks that did not (P=0.18). Prolonged pauses have a negative association with survival not explained by chest compression fraction or decreased ventricular fibrillation termination rate. Ventricular fibrillation termination was not the mechanism linking pause duration and survival. Strategies shortening the longest pauses may improve outcome.

Mechanical chest compressions improved aspects of CPR in the LINC trial

AimWe studied resuscitation process metrics in patients with out-of-hospital cardiac arrest enrolled in a randomized trial comparing one protocol designed to best use a mechanical CPR device, with another based on the 2005 European Resuscitation Council guidelines for manual CPR. MethodsWe analyzed clinical data, ECG signals, and transthoracic impedance signals for a subset of the patients in the LUCAS in Cardiac Arrest (LINC) trial, including 124 patients randomized to mechanical and 82 to manual CPR. Chest compression fraction (CCF) was defined as the fraction of time during cardiac arrest that chest compressions were administered. ResultsPatients in the mechanical CPR group had a higher CCF than those in the manual CPR group [0.84 (0.78, 0.91) vs. 0.79 (0.70, 0.86), p<0.001]. The median duration of their pauses for defibrillation was also shorter [0s (0, 6.0) vs. 10.0s (7.0, 14.3), p<0.001]. Compressions were interrupted for a median of 36.0s to apply the compression device. There was no difference between groups in duration of the longest pause in compressions [32.5s vs. 26.0s, p=0.24], number of compressions received per minute [86.5 vs. 88.3, p=0.47], defibrillation success rate [73.2% vs. 81.0%, p=0.15], or refibrillation rate [74% vs. 77%, p=0.79]. ConclusionsA protocol using mechanical chest compression devices reduced interruptions in chest compressions, and enabled defibrillation during ongoing compressions, without adversely affecting other resuscitation process metrics. Future emphasis on optimizing device deployment may be beneficial.

Abstract 277: Supraglottic Airway Use Is Associated with Higher Chest Compression Fraction than Endotracheal Intubation During Out-of-Hospital Cardiopulmonary Arrest

Objective: Chest compression interruptions - such as those from endotracheal intubation (ETI) - are associated with poorer out-of hospital cardiac arrest (OHCA) survival. Select Emergency Medical Services (EMS) practitioners substitute ETI with supraglottic airway (SGA) insertion to minimize these interruptions, but the resulting effects upon chest compression fraction (CCF) are unknown. We sought to determine the differences in CCF between adult OHCA receiving ETI and those receiving SGA. Methods: We studied adult, non-traumatic OHCA patients enrolled in the Resuscitation Outcomes Consortium (ROC) PRIMED trial. Chest compressions were measured using compression or thoracic impedance sensors. We limited the analysis to those receiving ETI or SGA and &gt;2 minutes of chest compression data before and after airway insertion. We compared CCF between ETI and SGA before and after airway insertion, adjusting for age, sex, witnessed arrest, bystander CPR, shockable initial rhythm, public location, PRIMED trial arm, and regional ROC center. We also compared the change in CCF for each airway technique and stratified these analyses by initial rhythm. We analyzed the data using t-tests and multivariable linear regression. Results: Of 14,955 patients enrolled in the ROC PRIMED trial, we analyzed 2,767 cases, including 2051 ETI, 671 SGA, and 45 both. Unadjusted pre- and post- airway CCF was higher for SGA than ETI (pre- 0.732 vs 0.706, difference -0.026 95% CI -0.044, -0.008; post- 0.767 vs 0.724, difference -0.043 95% CI -0.060, -0.026). Adjusted post-airway CCF improved with both techniques, but the changes were not statistically significant (0.012 difference, 95% CI 0.036, -0.012, p-value 0.32). CCF differences were similar when stratified by initial rhythm. Conclusion: In this series SGA insertion was associated with a higher CCF than ETI and that difference persisted post-airway insertion. Advanced airway management strategy may minimally impact CCF.