bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract Su302: Impact of Time to Defibrillation on Mortality after In-Hospital Cardiac Arrest
Authors: Shinn Jordan , Bodempudi Sairamya , Howarth Eileen , Maglione Theodore , Coromilas James
Published: November 2024

Background:
In-hospital cardiac arrest occurs in 290,000 patients annually in the United States, with less than 20% of these arrests featuring a shockable presenting rhythm. The three-phase model of CPR is separated into the electrical phase which occurs in the first 4 minutes, the circulatory phase which includes minutes 4-10, and the metabolic phase which is greater than 10 minutes from arrest onset. Defibrillation during the electrical phase has been proven to improve survival by approximately 50%. Current guidelines recommend defibrillation within the first 2 minutes of arrest in those with a rhythm of VT/VF.

The purpose of this study was to determine the effect of time to defibrillation on mortality in patients with shockable rhythms.

Methods:
Full-disclosure rhythm strips for all cardiac arrests in non-ICU patients on telemetry were reviewed from Feb 2019 to April 2023. Time to defibrillation of shockable rhythms (VT/VF) was determined from the telemetry data and corresponding defibrillator data from the Zoll CodeNet electronic system.

Results:
We identified 32 of the 186 patients with cardiac arrest while on telemetry presenting with pulseless monomorphic VTor polymorphic VT/VF. The average time to defibrillation was 4.8 min ± 2.7 min. 34% of patients were defibrillated in 4 minutes or less from the onset of the arrythmia, 31% were defibrillated in more than 4 minutes from the onset of the arrythmia, and 34% were not defibrillated. Patients defibrillated in 4 minutes or less had a significantly lower mortality of 36.4% compared to a 50% mortality of those defibrillated in more than 4 minutes and 90.9% mortality in those not defibrillated (p<0.05).The patients who were not defibrillated were determined to have ongoing VT or poly VT/VF until telemetry was removed and the Zoll defibrillator pads were applied. They were ultimately deermined ot have PEA and were not shocked.

Conclusions:
Patients defibrillated in 4 minutes or less from the onset of a sustained shockable arrythmia experienced significantly lower mortality during hospitalization compared to those who were defibrillated in more than 4 minutes or were not defibrillated. 34% of patients with a shockable rhythm were not defibrillated due to a diagnosis of PEA after the Zoll pads were placed. Patients with sustained VT/VF causing in-hospital cardiac arrest should be defibrillated as soon as a defibrillator can be applied. Telemetry data should be clearly communicated to the code team.
Abstract Su303: Afferent Rapid Response Limb Failure Prior to Non-ICU In-Hospital Cardiac Arrest and Associated In-Hospital Mortality
Authors: Shipley Kipp , Shifrin Megan , Snarskis Connor , Weavind Liza
Published: November 2024

Introduction/Background:
Rapid Response Teams (RRT) have been widely implemented to recognize and manage clinical deterioration outside of the intensive care unit (ICU). Hospital systems frequently rely on individual healthcare provider’s skill and attention to identify early deterioration and activate the appropriate clinical resources. This is referred to as the afferent limb, or triggering mechanism, of the Rapid Response system.

Hypothesis:
Afferent limb failure leads to delayed clinical intervention and potentially worse outcomes for patients that progress to in-hospital cardiac arrest (IHCA).

Goals/Aims:
The aim of this retrospective study was to identify if afferent limb failure, defined as failure to recognize two or more standardized early warning criteria in the 24 hours prior to non-ICU IHCA, is associated with increased in-hospital mortality when compared to patients with zero to one standardized early warning criteria.

Methods:
Non-ICU IHCAs over a 6-year period (January 1
st
, 2018, to December 31
st
, 2023) at a large academic medical center were reviewed using standardized criteria to determine 1) if any RRT activation criteria had been met in the 24 hours prior to non-ICU IHCA, 2) how many RRT criteria were met, 3) whether an RRT activation occurred, and 4) in-hospital mortality. Statistical analysis included a Chi-Square analysis and Pearson Correlation Coefficient.

Results:
We identified 386 adult non-ICU IHCAs, with 214 (55.4%) meeting at least two RRT criteria in the 24 hours preceding their non-ICU IHCA. In patients without a preceding RRT activation (N=313), there was significantly higher in-hospital mortality in patients who met two or more RRT criteria prior to their non-ICU IHCA than patients who met one or zero criteria (91/151, 60.2% vs 114/162, 70.3%, p < 0.05). We also found a weak but statistically significant correlation between the total number of RRT criteria met prior to IHCA and in-hospital mortality (r=0.1331, p < 0.05).

Conclusion:
Afferent limb failure is associated with higher in-hospital mortality in patients with multiple markers of clinical deterioration prior to non-ICU IHCA. There is also an association between in-hospital mortality and the total number of clinical deterioration criteria met prior to non-ICU IHCA.
Abstract Su304: The Effect of Time to DC Shock on Return of Spontaneous Circulation in Out-of-Hospital Cardiac Arrest with Recurrent Shockable Rhythm
Authors: Awad Emad , Klapthor Brent , Morgan Michael , Youngquist Scott
Published: November 2024

Objective:
The optimal timing for defibrillation attempts in out-of-hospital cardiac arrest (OHCA) patients with recurrent shockable rhythms [ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT)] is uncertain. This study examined the association between "time to DC shock" and the return of spontaneous circulation (ROSC) in OHCA patients with recurrent shockable rhythms.

Methods:
This was a retrospective analysis of data from the Salt Lake City Fire Department (SLCFD) from 2012 to 2023. Rhythm-filtering technology, used since 2012, enabled real-time and accurate interpretation of cardiac rhythms during CPR, with local protocols allowing early defibrillation for recurrent VF/ pulseless VT cases. Patients who experienced four or five episodes of shockable rhythms and received defibrillation were included. Generalized estimating equation (GEE) analysis was used to evaluate the association between time to shock preceding recurrent defibrillation and ROSC.

Results:
A total of 142 patients were included, with a mean age of 59.7 ± 15 years; 105 (73.9%) were male, 63 (44.4%) arrested in public locations, and 101 (71.1%) had witnessed arrests. Adjusted GEE analysis revealed that longer time to shock was associated with lower odds of achieving ROSC (OR: 0.81, 95% CI: 0.72–0.93, p = 0.005). Every one-minute delay in defibrillation is predicted to decrease the likelihood of achieving ROSC by 19%.

Conclusion:
In patients with recurrent shockable rhythms, every one-minute delay in delivering a shock was associated with a statistically significant 19% reduction in the chance of achieving ROSC. This finding highlights the importance of reducing the time to defibrillation in managing recurrent shockable rhythms and suggests reevaluating the current recommendation of two-minute intervals for rhythm check and shock delivery.
Abstract Su305: Chest Compression Fraction, Bag-mask Ventilation, And Survival From Out-of-hospital Cardiac Arrest: A Multicenter Study
Authors: Yang Betty , ARAMENDI ELISABETE , Leroux Brian , Jaureguibeitia Xabier , Shaver Sarah , Chang Mary , Rea Thomas , Kudenchuk Peter , Christenson Jim , Vaillancourt Christian , Callaway Clifton , Salcido David , Carson Jonas , Blackwood Jennifer , Wang Henry , Idris Ahamed
Published: November 2024

Background:
Ventilation during cardiopulmonary resuscitation (CPR) is poor. Better lung inflation during chest compression pauses is associated with better return of spontaneous circulation (ROSC), survival, and functional neurological survival. Chest compression quality, quantified by chest compression fraction (CCF) >80%, has also served as a guideline target for improved outcomes. We hypothesized that greater chest compression fraction modifies the association between ventilation quality and outcomes.

Methods:
We studied patients suffering out-of-hospital cardiac arrest from six sites of the Resuscitation Outcomes Consortium (ROC) Trial of Continuous or Interrupted Chest Compressions during CPR. We performed a subanalysis of patients assigned to the 30:2 CPR arm with ≥ two minutes of thoracic bioimpedance signal recorded with a cardiac defibrillator/monitor. Detectable ventilation waveforms were defined as having a bioimpedance amplitude ≥0.5 Ohm (corresponding to ≥ 250 ml tidal volume) and duration ≥1 sec. We defined a chest compression pause as a break in chest compressions of 3 - 15 sec duration. We dichotomized ventilation into two groups: 1) better lung inflation (≥ one lung inflation waveform in ≥50% of chest compression pauses), and 2) poor lung inflation (waveforms in <50% pauses). We analyzed CCF during bag-mask prior to intubation (if any). We used multivariable logistic regression to assess the relationship among CCF, ventilation, and the outcomes of ROSC, survival, and functional neurologic survival.

Results:
Among 1,976 patients, mean age was 65 years, 66% were male. Most patients received poor ventilation (60%, n=1177) over ventilation over 9.8 ± 4.9 minutes. Median CCF was 0.78 (0.71, 90.84) and 0.78 (0.70, 0.83) for poor and better lung inflation, respectively. For CCF <85%, survival was significantly greater in those who received better ventilation, when compared to poor ventilation, and had greater pauses per minute (Figure A). The beneficial interaction between ventilation and outcome was greater with CCFs of 85% or less, compared to higher CCFs (Figure B). With CCFs >85%, survival did not improve significantly with better ventilation. These results persisted after adjustment for Ustein variables and ROC site.

Conclusions:
We observed improved survival with better ventilation until CCF exceeded 85% in the preintubation period, suggesting an optimal strategy with better ventilation and chest compression fractions of 85% or less.
Abstract Su306: Impact of Ventricular Fibrillation on Myocardial Infarct Size: A Clinical and Experimental Study
Authors: STEVIC Neven , Pinede Alexandre , Mewton Nathan , Argaud Laurent , Ovize Michel , Lecour Sandrine , Bochaton Thomas , cour martin
Published: November 2024

Background:
Ventricular fibrillation (VF) - induced cardiac arrest is a frequent complication of ST-segment elevation myocardial infarction (STEMI). Although larger infarct sizes (IS) are associated with a higher risk of VF, there has been no investigation into the influence of VF itself on IS. To address this knowledge gap, we analyzed the impact of VF on IS in patients and 2 experimental models.

Methods:
From the prospective cohort HIBISCUS-STEMI, 30 STEMI patients with VF were matched on common determinants of IS in a 1:2 ratio with patients without VF. The primary endpoint was IS, assessed using the 48-hour area under the curve (AUC) for troponin. We compared IS in pigs with/without spontaneous VF during STEMI (n=15/group), and in an isolated rat heart model of acute myocardial infarction with/without electrically induced VF (n=7/group); IS was assessed using the ratio of the area of necrosis (AN) to the area at risk (AAR).

Results:
While patient characteristics were similar after matching (including AAR), IS was 33% lower in the VF group than in the control group (troponin AUC 1.6 [0.5-3.3] 10
6
vs. 2.4 [0.9-4.1] 10
6
arbitrary units; p=0.049). In pigs, IS was lower (p<0.01) in the VF group (24% [11-40]) than in controls (71% [48-75]). In the isolated heart model, IS was lower (p<0.05) in the VF group (9% [7-15]) than in controls (42% [38-44]).

Conclusion:
When common determinants of IS are comparable, the occurrence of VF prior to MI reperfusion is associated with significantly smaller IS.
Abstract Su402: Comprehensive Assessment of Chest Compression Quality Across All Phases of Prehospital Care Using a Manikin
Authors: FUJITA KENSUKE , Douno Eri , Hanafusa Hiroaki , Inoue Akira , Hagiwara Yoshihiro , Ogura Takayuki
Published: November 2024

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.
Abstract Su404: Time difference between pad placement in double versus single external defibrillation: a live patient simulation model
Authors: Nordviste Vegard , Kruger Andreas , Rehn Marius , Brede Jostein
Published: November 2024

Background:
Out-of-hospital cardiac arrest (OHCA) cause significant patient morbidity and mortality. Double sequential external defibrillation (DSED) represents an alternative treatment for OHCA patients, but the use is currently reserved for patients in refractory ventricular fibrillation. However, OHCA patients may achieve return of spontaneous circulation earlier with the use of DSED as the initial treatment.

Aims:
To compare the necessary times needed to establish pad placement in DSED compared to standard pad placement in a live patient simulation model.

Methods:
This study was an observational cohort study with ambulance personnel and live patient models. Two-member teams established two defibrillators ready for rhythm analysis. Time spent for standard pad placement and DSED was registered in the same procedure. The procedure was performed on two patient categories, with BMI 20,9 (patient A) and BMI 32,8 (patient B). All team members performed the procedure on both patient categories.

Results:
In total, 108 procedures were performed on both patient categories. Mean difference in time needed for DSED versus standard pad placement was 13.7 ± 4.8 seconds for patient A, and 13.9 ± 4.6 seconds for patient B. There was no significant difference in time spent between the two patient categories (p=0.725).

Conclusion:
The necessary time to establish DSED versus standard defibrillation pad placement was short. This may support clinical studies on DSED as initial treatment for OHCA patients without risk of significant increase in time to first defibrillation.
Abstract Su405: Effect Of A Visual Feedback Device On The Acquisition Of Cardiopulmonary Resuscitation Skills In Training Certified By The American Heart Association: Randomized Clinical Trial
Authors: Castro Carina , Vaz Jacqueline , Oliveira Tripoli de Mattos Mariana , Barbisan Juarez
Published: November 2024

Background:
High-quality cardiopulmonary resuscitation (CPR) is fundamental for the success in the care of cardiorespiratory arrest. In CPR skills training, manequins with feedback on quality parameters have been employed and received varied evaluative results. The American Heart Association (AHA) encourages the use of feedback devices in CPR training; however, its effects have not been evaluated in courses certified by it.

Research Questions:
Training with visual feedback devices alters the learning of students in acquiring psychomotor skills in CPR?

Goals:
To evaluate the effect of a visual feedback device on CPR training, in AHA certified courses.

Methods:
A randomized clinical trial was conducted to estimate the intervention of a visual feedback device in practical CPR training for nurses, medical students and physicians in the Advanced Cardiovascular Life Support (ACLS) courses. For that, having as parameters the quality criteria determined by the AHA, we tried to compare the performance results of the trained students with objective feedback from the device and the trained students with subjective feedback from the instructor. Statistical analysis included chi-square test, Student's t test, Mann-Whitney u test, Spearman’s-rho correlation coefficient. Significance level considered was 0.05. A survey was registered with ClinicalTrials®, under resgistration NCT 04338490.

Results:
The sample consisted of 209 students; of these 119 (56.9%) were women, and 148 (70.8%) were physicians. The control group had 98 students, and the intervention group 111 students. The performance of students from both groups reached the criteria of quality in CPR. The group trained with a feedback device achieved, according to guidelines, better results in the rate of chest compressions, 78 (70.3%) versus 48 (49.0%), p <0.01, and in return of the chest 100 (91; 100) versus 99 (78.25; 100), p <0.03. As for the recommended compression fraction, 60% to 80%, both groups were above 60%; however, no student in the study reached 80%.

Conclusions:
The visual feedback device was effective in CPR training, improving students’ performance in the criteria of compression rates between 100 and 120/min and total return of the chest between compressions.
Abstract Su406: Acceptability and Effectiveness of a Novel, Video-Based CPR and AED Education Program in Canadian Schools
Authors: Allan Katherine , McCulloch Holly , Ruether Kim , Zotzman Jeanine , Blanchard Ian , Janczyszyn Mike , Wong Natalie , ONeil Emma , Sapp John , DHILLON Santokh
Published: November 2024

Background:
Early cardiopulmonary resuscitation (CPR) and defibrillation are critical for favorable outcomes after sudden cardiac arrest (SCA). Scientific evidence supports CPR and Automated External Defibrillator (AED) training in school-age children. Few studies have used gamified, video-based training to teach students. This national project aimed to assess the acceptability and effectiveness of a brief, video-based educational program (CardiacCrash™), developed by the Heart and Stroke Foundation to teach students hands-only CPR and AED use within a classroom setting.

Methods/Results:
This study reports preliminary data from two Canadian provinces (Ontario, Alberta). The acceptability and effectiveness of training was measured using a pre/post survey evaluating students’ self-confidence in recognizing SCA, calling for help, and providing bystander CPR, including the use of an AED. CPR performance was measured by using Little Anne QCPR manikins that collected data on CPR effectiveness throughout the training session. Results are stratified by student cohort (elementary—grades 4-8, and secondary—grades 9-12).

A total of 1273 students from 6 Ontario and 7 Alberta schools were trained between October 2023 to April 2024. The average age for elementary students (n=729; 47.3% male) was 11.2 ± 1.3 years, and 39.9% had previous CPR training. The average age for secondary students (n=544; 54.4% male) was 15.5 ± 1.1, and 42.6% had previous CPR training. Both groups thought the training was easy (86%), fun (81%), the correct duration (59%) and would recommend it to their friends (85%).

All outcome variables improved post-training for both elementary and secondary students, including the self-confidence to recognize and assist in cases of SCA (p=0.008 for both cohorts), (Figure 1). Secondary students were significantly better at providing effective compressions vs. elementary for most CPR measures (Table 2).

Conclusion:
Preliminary data suggest that CardiacCrash™, a video-based educational program, is acceptable to school-age students and effective at teaching them to perform CPR and use an AED. While both elementary and secondary students achieved acceptable CPR performance, secondary students performed higher quality CPR.
Abstract Su407: Implementing An Effective Standardized Bystander CPR Protocol For US Golf Courses
Authors: Casey Donald , Adelman Mark , Baumgarten Clara , Butler Mark , Collins Michael , DiClementi David , Fenton Mitchell , Pastore Luke , Smith Craig , Tansey William
Published: November 2024

Background:
A golf course is the fifth most common public place for cardiac arrest (CA). Informal interviews with golfers and golf course personnel revealed striking incomplete and variable knowledge about what to do in the event of a CA on a golf course in accordance with most current bystander resuscitation guidelines.

Hypothesis:
We hypothesized that the development and implementation of a standardized protocol (called “911-CPR-AED”) for the three most critical first steps to assure aperson’s survival of an on-golf course CA will improve chances of surviving if playing partners, caddies and club staff are well prepared to respond urgently and appropriately to such an emergency.

Aim:
To successfully implement the standardized “911-CPR-AED” protocol for 4 different golf clubs.

Approach:
We achieved full support and involvement of the Club Boards, professional staff, club management, grounds crew and membership as well as coordination with local Emergency Medical Systems (EMS) and communications to all golfers and caddies. We created a specific four-panel laminated infographic customized for each club and designed to fit easily into every golfer’s bag and caddy vest, assuring a readily available “911-CPR-AED” guide for lay bystanders to notify EMS and Club staff, immediately initiate chest compressions, ensure rapid delivery of an AED and BLS certified persons to the arrest site, and safely guide EMS on their arrival. We also staged live “dry run’ simulations on the golf courses with all key team members and timed each and every step of the simulation from start to finish. All aspects of this process were shared with leaders of the closest EMS and hospital emergency departments (EDs).

Results:
Within the past 2 years, we have successfully implemented a standardized emergency resuscitation protocol we call “911-CPR-AED” at 4 different golf clubs for immediate initiation of bystander CPR in the event of full CA on a golf course. Since implementation, we have witnessed 3 CA events and achieved successful full “on course” resuscitations that deployed this protocol for all three survivors who are now back to playing golf. We intend to share the details and many lessons learned for these ongoing efforts.

Conclusion:
An effective, standard bystander CPR protocol now exists for use at any US golf course. We intend to expand Implementation to 3 new golf courses and will continue to raise awareness and encourage widespread local implementation across the US.
Abstract Su501: Feasibility and Implications of Electrocardiogram-based Prediction of Incessant Refractory Ventricular Fibrillation
Authors: Coult Jason , King Julia , Kwok Heemun , Bhandari Shiv , Blackwood Jennifer , Johnson Nicholas , Sayre Michael , Daya Mohamud , Rea Thomas , Kudenchuk Peter
Published: November 2024

Background:
Refractory ventricular fibrillation (R-VF) patients, defined as requiring ≥ 3 shocks during resuscitation of OHCA, have relatively poor outcomes. Prior studies have predicted R-VF using the ECG, suggesting potential to guide early patient-specific treatment for R-VF. However, R-VF comprises multiple phenotypes with distinct defibrillation response profiles: Incessant VF (no shocks terminate VF), recurrent VF (all shocks terminate VF but VF recurs), or mixed VF (shocks variably terminate VF). These phenotypes may have distinct prognoses, and may also respond differently to R-VF treatments such as early antiarrhythmics, modified vasopressor dosing, alternative defibrillation strategies, or expedited invasive interventions. Early prediction of specific R-VF phenotype could potentially improve outcome through preemptive targeting of treatment to individual phenotype.

Aim:
We sought to predict incessant R-VF using machine learning analysis of the defibrillator ECG.

Methods:
We performed a retrospective study of adult VF OHCA treated by EMS from 2006–2019 in King County WA. We linked a clinical OHCA registry with defibrillator recordings to evaluate ROSC and survival to hospital discharge by VF type (non-refractory; or incessant, recurrent, or mixed R-VF prior to the third shock). To predict incessant R-VF specifically, we used a series of four 2-s ECG segments from each patient within 60s surrounding the first shock. Patients were randomized 65%/35% for training/test. A support vector machine classifier was trained to predict subsequent incessant R-VF using ECG scalograms. Algorithm performance was assessed by area under the receiver operating characteristic curve (AUC) and by sensitivity at >75% specificity.

Results:
Of 1111 included VF patients, median age was 62, 241 (22%) were female, 658 (59%) were refractory (≥ 3 shocks), 800 (72%) achieved ROSC, and 520 (47%) survived. The incessant R-VF phenotype accounted for 10% (N=116) and had worse ROSC and survival compared to recurrent R-VF and non-refractory patients (Table). Training and test AUCs to predict incessant R-VF were 0.77 (95% CI: 0.72–0.82, N=723) and 0.76 (95% CI: 0.66–0.82, N=388) respectively. Test sensitivity and specificity were 64% and 76%.

Conclusion:
Refractory VF comprises distinct phenotypes with disparate outcomes. Incessant R-VF has notably poor prognosis. Machine learning may be able to predict incessant R-VF, potentially guiding preemptive, patient-specific treatments to improve outcome.
Abstract Su503: Relationships Between Quantitative ECG Measures and Defibrillation Success in Early Ventricular Fibrillation
Authors: Forghani Rameen , Gumucio Jorge , Menegazzi James , Salcido David
Published: November 2024

Introduction:
Rapid termination of ventricular fibrillation (VF) has long been recognized as the cornerstone of effective cardiac arrest resuscitation. In recent years, amplitude spectral area (AMSA) has been shown to be highly associated with defibrillation success, and AMSA has been experimentally used to personalize defibrillation timing and strategy. However, questions remain about whether the interpretation of AMSA holds uniformly in varied conditions, such as ultra-early or prolonged cardiac arrest or after anti-arrhythmic administration.

Hypothesis:
AMSA is greater after 20 seconds of untreated VF compared to 50 seconds of untreated VF; a higher AMSA predicts greater first-defibrillation success.

Methods:
VF was induced in adult swine (n = 3) with a bipolar pacing catheter placed in the right ventricle. Animals were randomized to 20- or 50-second-long episodes of VF (n = 123), followed by standard 150 J biphasic defibrillation. In MATLAB, AMSA was calculated as the summed product of frequency and square root of power after Fast Fourier Transform for the four second period of VF immediately prior to defibrillation. Results were analyzed by a two-sided Chi-squared test or ANOVA with Tukey’s HSD in R; a p-value < 0.05 was considered significant.

Results:
First shock success was lower in the 20-second-VF group compared to the 50 second group (31/78 (39.7%) vs 31/45 (68.8%), p = 0.003). The AMSA at 20 seconds was significantly higher for successful compared to unsuccessful first defibrillation (8.20 vs. 7.31 mV-Hz, p = 0.034). The AMSA at 50 seconds was not statistically different between successful and unsuccessful defibrillations (6.32 vs. 5.67 mV-Hz, p = 0.470). Evaluating the AMSA after a duration of VF irrespective of shock success, AMSA was higher at 20 seconds compared to 50 seconds (7.66 vs 6.12 mV-Hz, p < 0.001).

Conclusion(s):
AMSA decreases from 20 to 50 seconds of untreated VF, and higher AMSA at a given time point is associated with greater first defibrillation success. However, first defibrillation success was higher after 50 seconds of untreated VF compared to 20 seconds, raising questions about special cases, such as edge effects, that may influence AMSA interpretation.
Abstract Su505: Impact of a Targeted Automated External Defibrillator (AED) Program on Survival After Ventricular Fibrillation Cardiac Arrest in the Sao Paulo Metropolitan Subway System: A Landmark Initiative in Latin America
Authors: Timerman Sergio
Published: November 2024

The targeted Automated External Defibrillator (AED) program in the Sao Paulo Metro has yielded promising results in improving survival rates for individuals experiencing out-of-hospital cardiac arrest (OHCA) due to ventricular arrhythmias. A longitudinal observational study conducted from September 2006 to November 2023 assessed the program's impact on survival outcomes.

The implementation of the full program led to a significant improvement in survival to hospital discharge with minimal neurological impairment (0% vs. 43%, P=0.001). These findings underscore the importance of a targeted AED program in improving survival outcomes for OHCA, particularly in densely populated urban environments such as the Sao Paulo Metro. The short interval between arrest and defibrillation emerged as a critical factor in achieving favorable long-term, neurologically intact survival rates.

The success of this program advocates for the strategic expansion of targeted AED initiatives in other large Latin American cities, emphasizing the potential to save lives and enhance public health outcomes through proactive emergency medical response measures.
Abstract Su506: A Comparison of Synchronized Versus Unsynchronized Mechanical Chest Compressions in a Swine Model
Authors: Marill Keith , Menegazzi James , Gumucio Jorge , Salcido David
Published: November 2024

Background:
The proportion of cardiac arrest presenting with pulseless electrical activity (PEA), which includes pseudo-PEA, is increasing and survival remains dismal. We hypothesized that mechanical chest compressions synchronized to native cardiac contractions improve coronary perfusion pressure (CPP) during resuscitation of pseudo-PEA.

Methods:
We developed a model of pseudo-PEA by infusing high dose esmolol intravenously into anaesthetized, intubated, and central arterial and venous catheterized swine to a goal of 45 mm Hg mean arterial blood pressure (MAP). We then provided alternating synchronized and unsynchronized chest compressions for 52 seconds preceded by 8 second breaks consecutively four times. We repeated the protocol two to three times with one minute breaks after each four minute block. Synchronized compressions were provided 1:1 with native contractions during systole and unsynchronized compressions were provided at 100 beats per minute (BPM). We measured average CPP, MAP, and heartrate (HR) for 5 beats immediately preceding the onset of chest compressions and for 30 seconds 10 seconds after the onset of compressions. We computed the difference in continuous CPP during compressions compared to the immediately preceding baseline for each interval. We developed a mixed linear model with outcome variable average CPP during compressions minus baseline, fixed variable compression type, and random variable animal.

Results:
We included four animals. Mean baseline HR was 78.9 BPM, MAP 55.2, and CPP 44.0. Chest compressions increased CPP from baseline an average 4.0 mm Hg when unsynchronized and 6.4 mm Hg synchronized. The adjusted difference was 2.5 mm Hg (95% CI 0.3 – 4.6).

Conclusions:
Synchronized chest compressions significantly increased CPP 2.5 mm Hg (62%) more than unsynchronized chest compressions despite a lower compression rate in a medication-induced swine model of pseudo-PEA. Further refinement and application to patients suffering pseudo-PEA cardiac arrest appear warranted.
Abstract Su601: Missed Hypoxia in the Prehospital Care of Major Traumatic Brain Injury: Discrepancies Between Continuous Monitor Data and Clinical Documentation
Authors: Spaite Daniel , Barnhart Bruce , Jorgenson Dawn , Burgett Kevin , Rice Amber , GAITHER Joshua , Keim Samuel , Hu Chengcheng
Published: November 2024

Background:
It is well established that prehospital hypoxia dramatically increases mortality in Traumatic Brain Injury (TBI). Thus, in EMS TBI research, case ascertainment and risk adjustment are highly dependent upon documentation of in-field O

2

saturation (SpO

2

). Objective: To compare the rate of hypoxia identified by EMS personnel and documented in EMS patient care records (PCR) versus the actual rate of hypoxia recorded by continuous, non-invasive monitoring in TBI.

Methods:
A subset of major TBI cases (moderate/severe) from 5 EMS agencies reporting monitor data (Philips MRx™) in the EPIC EMS TBI Study (NIH 1R01NS071049) were evaluated (02/13-02/18). All monitor data available for post-hoc review were displayed and accessible to the providers during EMS care. We compared PCR documentation of hypoxia (SpO

2

<90%) to continuous monitor data in TBI patients (nasal canula O

2

, mask, basic or advanced airway). Statistic: exact McNemar’s test, α=0.05.

Results:
120 cases were included [med. age 50; IQR (23.8, 68); 65% male. Monitors recorded 44 hypoxic cases (36.7%; 95%CI 28.1, 45.9%). Only 8 (6.7%; 2.9, 12.7%) were documented in the PCR (p<0.0001; Figure). Three machine-detected hypoxia cases had no PCR-documented SpO

2

at all.

Conclusions:
The difference in PCR-documented and monitor-identified hypoxia was dramatic. The monitor data revealed a five-fold greater incidence of hypoxia than that documented by EMS providers. This may be partially explained by the continuous nature of pulse oximetry in the face of ongoing care responsibilities and scene distractions. The field environment may cause providers to miss low readings as they fluctuate moment-by-moment. These findings have major clinical implications. While some of the discrepancy between PCR reporting and monitor data might simply be failure to document hypoxia, the much more concerning implication is that many cases might be unrecognized and untreated. Furthermore, these findings have important implications for case ascertainment, confounding, and risk-adjustment in EMS TBI research. Whenever possible, quality improvement and research projects should utilize continuous non-invasive monitor data to identify and evaluate hypoxic patients in the setting of TBI. These findings may also have implications for identifying hypoxia in EMS patients with other critical conditions.
Abstract Su604: Telecommunicator Guided Repositioning to the Floor During Out-of-Hospital Cardiac Arrest
Authors: Missel Amanda , Pinnock Cameron , Maironis Daniel , Rooney Deborah , Tsutsui Julia , Wilson Nicholas , Neumar Robert , Bir Cynthia
Published: November 2024

Background:
Current guidelines advise people to reposition a patient in need of cardiopulmonary resuscitation (CPR) to a firm surface. Repositioning is associated with longer time to first compression and a lower likelihood of bystander CPR. Older adults often have comorbidities that increase the risk for injury during repositioning.

Aims:
The aim of this research was to develop and evaluate the quality of a novel telecommunicator-CPR (TCPR) repositioning intervention.

Methods:
This study was conducted in two phases that employed a biomechanical surrogate containing head sensors. In Phase 1, our novel intervention was tested against three other TCPR scripts (A-general instructions, B-using sheet, C-pulling legs). Participants completed simulated 911 calls with all four scripts and were randomized to the order they completed them. The primary outcome was time to reposition, and the secondary outcome was risk for injury, determined by the head injury criterion (HIC). The novel intervention script (D) was revised based on feedback from participants and video review. In Phase 2, our revised TCPR intervention was tested against script A with participants randomized to either script received. The difference between groups’ time to reposition and risk for injury was determined using Kruskal-Wallis for Phase 1 and Wilcoxon Rank Sum for Phase 2.

Results:
Phase 1 had 35 participants, were 60% female with a mean (M) age of 45 years (19 SD) and 94% reported exercising weekly. One participant was unable to reposition the manikin to the floor using scripts A or B. Time to reposition was shortest for script C (M= 30 secs) and longest for novel script D (M= 99 secs, p<.001, Table 1). Risk for injury was highest for script B, using the sheet, and lowest for novel script D, p=0.004. Phase 2 had 36 participants, were 56% were female with a mean age of 45 (18 SD). Time to reposition was shorter for script A, general instructions (p<.001), and risk for injury was similarly very low in both scripts A and D (Table 1).

Conclusions:
Findings suggest use of a sheet or pulling on legs may increase the risk for injury and needs further study. General instructions, which allow the bystander to determine the best approach, had the shortest time to reposition while maintaining a low risk of injury. Our novel script resulted in the longest time to reposition but had a low risk of injury. Further study is warranted to test whether the time to deliver instructions could be shortened.
Abstract Su605: Return of Spontaneous Circulation after Transport with Ongoing Cardiopulmonary Resuscitation: Is Transport Always Futile?
Authors: Root Christopher , White Chelsea , Selby Sasha , Harrell Andrew , Fisher Benjamin , Braude Darren , Huebinger Ryan
Published: November 2024

Introduction:
Despite validated Termination of Resuscitation (TOR) rules for Out of Hospital Cardiac Arrest (OHCA) some OHCA patients are transported prior to Return of Spontaneous Circulation (ROSC), sometimes with long transport times. There are certain therapies unavailable in the prehospital setting which could make transport prior to ROSC beneficial for some OHCA patients.

Hypothesis:
We hypothesized that longer transport times for patients with ongoing Cardiopulmonary Resuscitation (CPR) would be associated with progressively lower probability of achieving ROSC.

Aims:
To determine if there is a transport time interval beyond which ROSC becomes so unlikely that transport time could be determinant factor for TOR.

Methods:
We performed a retrospective study of the 2020-2022 NEMSIS national prehospital dataset. We included adult OHCA patients that did not have ROSC prehospital, were transported to the hospital, and had outcome and timestamp data available. We calculated transport time for each encounter and stratified encounters into 5-minute transport time intervals. We defined our outcome as ROSC after transport. We used multivariable logistic regression evaluating the association between 5-minute increases in transport time and ROSC. We performed a secondary analysis of patients that met termination of resuscitation (TOR) criteria (unwitnessed OHCA with no CPR or AED placement prior to EMS arrival).

Results:
Of 1,409,692 OHCAs, we included 137,957 OHCAs that were transported without prehospital ROSC. The median transport time was 8.9 minutes (IQR 5.4-13.8), and 17,957 (13.1%) had ROSC after hospital arrival. In 5-minute intervals from 0-30 minutes, ROSC rates were 13.5%, 13.1%, 12.0%, 11.1%, 12.1%, and 13.9%. Odds of ROSC per 5-minute increase in transport time was 1.00 (95% CI 1.00-1.00). For patients that met field TOR criteria, rates of ROSC for each 5-minute interval from 0-30 minutes were 9.2%, 8.7%, 7.6%, 5.9%, 6.1%, 4.2%, 7.5%. Odds of ROSC per 5-minute increase in transport time was 0.93 (95% CI 0.88-0.98).

Conclusion:
In this dataset we were unable to identify a transport time interval up to 30 mins beyond which transport is futile, even in patients who were transported despite meeting the universal TOR rule. Decision to transport based on case-by-case OHCA characteristics could have influenced results. Further research is needed to identify the subset of patient in whom transport prior to ROSC may be beneficial.
Abstract Su606: PulsePoint Alert Location Features in a Mid-Sized Metropolitan Area
Authors: Kates Leo , Chiaberta Alexandria , Gumucio Jorge , Weiss Leonard , Doshi Ankur , Salcido David
Published: November 2024

Introduction:
PulsePoint is a smartphone-based system that alerts layperson responders to out-of-hospital cardiac arrest (OHCA) events in non-residential locations within the United States. These locations can be classified to inform public access defibrillator (PAD) placement and focus responder training and recruitment efforts in high-frequency areas. Our objective was to manually classify the locations of PulsePoint alerts to better understand how PulsePoint performs across a variety of location types.

Methods:
Records were obtained for each PulsePoint alert in Allegheny County, PA, USA (pop. 1.2M) from 06/24/2016 to 10/28/2020. PulsePoint generates an alert when a potential OHCA occurs in public and is within 400m of at least one responder. Alert data contains address and location name, and the number and locations of nearby responders and PADs. We placed each location into one of the following categories: “education”, “consumer goods/services”, “restaurants/bars”, “transit hubs”, “hotels”, “entertainment venues”, “recreational facilities”, “government/municipal”, “offices”, “industrial/manufacturing”, “religious institutions”, “parks/outdoor spaces”, “sidewalk/street”, and “shelters/supportive housing”. “Unspecified/unknown” was used for locations that could not be classified due to insufficient information. We excluded all outpatient health, assisted-living, daycare, and correctional facilities. For each location category, we calculated the event count and the median number of nearby responders and PADs.

Results:
There were 994 included events during the capture period. The most frequent location category was “sidewalk/street”, which represented 24 percent of all alerts; the least frequent was “transit hubs”, which represented 0.7 percent of all alerts. “Shelters/supportive housing” had the highest median number of responders (7, IQR 1-14), while “industrial/manufacturing” had the lowest (1, IQR 1-3.5). “Transit hubs” had the highest median number of PADs (31, IQR 31-41), while “parks/outdoor spaces” had the lowest (0.5, IQR 0-1).

Conclusion:
PulsePoint alert-generating events occur across a wide variety of location types. Further research is needed to understand the accuracy of the system’s location data versus EMS dispatch records. Nonetheless, the data may have implications for system improvement by highlighting which location types have low numbers of nearby responders and PADs and may benefit from strategic PAD placements and training efforts.
Abstract Su607: Which would be major? witnessed collapse or bystander resuscitation?
Authors: Fan Cheng Yi , Sung Chih-Wei , Chiang Wen-Chu , HUANG CHIEN-HUA , Huang Edward Pei-Chuan
Published: November 2024

Background:
Witnessed collapse and bystander cardiopulmonary resuscitation (CPR) are two variables commonly used to predict outcomes in out-of-hospital cardiac arrest (OHCA). Some published studies have shown that bystander CPR were not significantly associated with outcomes after confounders adjusted. This may imply that witnessed collapse would be a superior prognostic factors beyond bystander CPR.

Hypothesis:
Witnessed collapse and bystander CPR may not contribute equally to prehospital return of spontaneous circulation (ROSC), and the former may be major.

Aims:
To investigate four prediction models for prehospital ROSC using stratification of the witnessed collapse and bystander CPR.

Methods:
The study enrolled OHCA patients treated by the emergency medical service (EMS) from January 2010 to December 2022 in three EMS systems in Taiwan. Data were extracted from the records of each medical service encounter, including patient demographics, dispatch timing, prehospital management, witnessed collapse and bystander CPR. The primary outcome was any prehospital ROSC. Patients were stratified into four groups by witnessed collapse (with/without) and bystander CPR (with/without) status, namely W+B+, W-B+, W+B- and W-B-. Prehospital ROSC prognostication were identified using multivariable logistic regression analysis.

Results:
The analysis comprised 17,323 patients, among whom 1,165 (6.7%) achieved prehospital ROSC. The W+B+ group demonstrated the highest prehospital ROSC rate at 13.0%, as compared with the other groups significantly (9.0%, 3.4%, and 4.1%, as depicted in Image 1). Stratification of the prehospital ROSC model (Image 2) indicated that the W+B+ group had several common predictors including age, traumatic arrest, no-flow time, public access defibrillation (PAD), and resuscitation events. However, certain predictors in other groups were removed during regression process. Notably, no-flow time significantly influenced prehospital ROSC only in the W+B+ and W+B- groups. Conversely, in the W-B- group, most variables had minimal impact on prehospital ROSC, reflecting the limited effectiveness of traditional predictors within this subgroup.

Conclusion:
The significance of witnessed collapse as a prognostic factor may be equal to or even greater than that of bystander CPR. Further studies are needed to confirm.