bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 203: Measurement of Cardiac Function in a Porcine Model of Cardiac Arrest Due to Massive Exsanguination
Authors: Berry John S , Batchinsky Andriy I , Belenkiy Slava M , Necsoiu Corina , Kendrick Chonna L , Ivey Katherine M , White Christopher E , Cohn Stephen M , Salinas Jose , Rasmussen Todd E , Dubick Michael A , Cancio Leopoldo C
Published: April 2024

Background:
While extremity hemorrhage can be stymied with a well placed tourniquet, vascular injury within the thorax and abdomen is not amenable to direct compression. Uncontrolled, noncompressible torso hemorrhage (NCTH) and the resultant cardiac arrest (CA) may account for up to 80% of preventable deaths in combat. We developed a porcine model of CA to test novel surgical interventions and are reporting measures of cardiovascular function during a simulated NCTH.

Methods:
Ten anesthetized Yorkshire pigs underwent tracheostomy, arterial and central line placement. Animals were awakened and sedated with midazolam titrated to a bispectral index of 75 ± 5. Spontaneously breathing, the animals were subjected to a computerized hemorrhage of 80% total blood volume (TBVH) over 20 minutes or until death, defined as mean arterial pressure (MAP)=0 mmHg and etCO2<10. During hemorrhage, if minute ventilation decreased 25% from baseline (BL) for >20 seconds, volume control ventilation was initiated. The Millar MPVS Ultra system continuously collected left ventricular (LV) and descending aortic pressures, as well as LV volume data via indwelling catheters. A repeated measures one-way ANOVA with Tukey’s procedure was performed on data collected at BL, 25%, 44%, 62% TBV hemorrhage, and CA, defined as a MAP<20 mmHg. Data are presented as means±SEM.

Results:
Weight was 63.8±2.8kg. TBVH at CA was 2941±130ml (71.0±1.5%). Time to CA was 18:22±00:40min. In Table 1, * denotes a significant change (p<0.05) in a variable from previous hemorrhage phase as marked by #.

Conclusions:
We developed a porcine model of CA secondary to exsanguination. We found that despite decreasing left ventricular volumes and pressures, cardiac contractility and conduction system function were maintained throughout hemorrhage. This suggests that lifesaving interventions (such as endovascular aortic balloon occlusion and extracorporeal life support) may be possible despite profound hypovolemia.
Abstract 205: Termination of Resuscitation Rules for Traumatic Cardiopulmonary Arrest: Old Dogma, New Validation
Authors: Huang Yu-Sheng , Chiang Wen-Chu , Ko Patrick Chow-In , Liu Sot Shih-Hung , Lin Chien-Hao , Chong Kah-Meng , Cheng Ming-Tai , Wang Hui-Chih , Yang Chih-Wei , Chen Shey-Ying , Lee Bin-Chou , Ma Matthew Huei-Ming
Published: April 2024

Introduction:
Pre-hospital terminations of resuscitation (TOR) rules for traumatic cardiopulmonary arrest (TCPA) have been proposed by the National Association Emergency Medical Physicians (NAEMSP) and the American College of Surgeons Committee on Trauma (ACSCOT) for a decade. However, validation studies from United Kingdom and Australia produced conflicting results. This study aimed to evaluate the performance of TOR rules for TCPA in an Asian metropolitan area.

Methods:
We analyzed data from an Utstein registry system of adult patients with TCPA in Taipei to test the performance of the first guiding criteria of TOR for TCPA: blunt trauma patient found in asystole upon the arrival of emergency medical service (EMS) at the scene. Predictive outcome was in-hospital death. Test statistics including sensitivity, specificity, positive predictive value (PPV), negative predictive values (NPV), and decreased transport rate (DTR) were calculated.

Results:
From Jan 1, 2008 to Dec 31, 2009, there were 328 adult patients with TCPA. The mechanism was blunt trauma in 155 (47.3%), penetrating trauma in 106 (32.3%) and uncertain in 106 (32.3%), and mechanisms were 155 (47.3%), 106 (32.3%), and 67 (20.4%). The presenting rhythm was asystole in 54/155 (34.8%) of blunt trauma, 57/107(53.3%) of penetrating trauma, and 28/67 (41.8%) of uncertain mechanism. Overall survival rate of TCPA (to hospital discharge) were 11/328 (3.4%). For those with blunt trauma, only 4 survived to hospital discharge (2.6%). The test statistics of the first guiding criteria (i.e. patients with blunt trauma and asystole) and sensitivity analysis by categorizing uncertain mechanism as blunt trauma were presented in the Table.

Conclusion:
Application of the first rule of thumb proposed by NAEMSP and ACSCOT for adult patients with TCPA can accurately identify non-survivors (100% PPV and 100% specificity) and decrease unnecessary EMS transports (16.5%~25.0%) in an Asian Metropolitan area.
Abstract 208: Emergency Medical Service Resuscitative Interventions in North-Central West Virginia Trauma Activation Criteria Patients: A Ten Year Experience
Authors: Whiteman Charles , Doerr Russell , Shaver Erica , Davidov Danielle , Davis Stephen M , Lander Owen , Blum Frederick
Published: April 2024

Introduction:
West Virginia (WV) is the second most rural state, with 51.3% of the population living in a rural area and 97.3% of the land area considered rural by the US Census Bureau. West Virginia University (WVU) MedCom provides medical command for Emergency Medical Services (EMS) in 26 north-eastern WV counties. EMS transport times often exceed 20 minutes in rural counties. However, little is known about the specific provider capabilities and interventions that occur in the rural pre-hospital setting.

Methods:
This was a retrospective, observational review of EMS interventions for “trauma activation criteria patients” (based on CDC Field Triage Guidelines) in the WVU MedCom database. Trauma activation criteria EMS encounters from January 1, 2002 to December 31, 2011 were analyzed for EMS provider capability, receiving hospital capability, and pre-hospital resuscitative interventions.

Results:
There were 11,853 patients available for analysis in the time period. Basic Life Support (BLS) providers provided 21.0% of the care. The distribution of receiving Trauma Centers was as follows: 83.2% Level I, 4.7% Level II, 3.9% Level III, 5.0% Level IV; 3.2% were taken to a facility without trauma center designation. Airway intervention occurred in 7.5% of patients; 2.3% had endotracheal tube (ETT) placement (0.88% had failed ETT placement), 0.34% had King/Combi-tube placement, and 4.0% had positive pressure ventilation with bag valve mask. Vascular access was attempted in 78.7% of the patients; 73.0% had vascular access established (72.9% by IV and 0.08% by intra-osseous access) and 5.1% had an IV fluid bolus administered. CPR was performed on 1.0% of the patients and needle thoracostomy was performed on 0.32% of the patients.

Discussion:

In rural north-central WV, BLS responders provided the pre-hospital care to 1 in 5 patients. Although treatment at a Level I Trauma Center has been shown to decrease patient mortality by 25%, only 83.2% of trauma patients in rural north-central WV were initially treated at a Level I Trauma Center. Pre-hospital airway intervention was needed in 7.5% of patients. Vascular access was established in only 73.0%; 5.1% received a fluid bolus. Additional studies will be needed to assess the impact of these treatments on patient outcomes.
Abstract 211: Blockade of Na+-Sensitive K+ Channels Alleviates Frequency-Dependent Electrical Failure in an Ex-Vivo Model of VF-Induced Cardiac Arrest
Authors: Garg Vivek , Taylor Tyson G , Venable Paul W , Sciuto Katie J , Shibayama Junko , Zaitsev Alexey
Published: April 2024

Ventricular fibrillation (VF), global ischemia and beta-adrenergic stimulation form the common context of sudden cardiac arrest. Regional and global loss of excitability under these conditions sets the stage of resuscitation failure due to either asystole or post-reperfusion VF recurrence. We hypothesized that Na+-sensitive K+ current (IKNa) significantly contributes to electrical failure under combined conditions of ischemia, high excitation frequency, and beta-adrenergic stimulation. We performed optical mapping of voltage-sensitive dye RH237 in the anterior right and left ventricle (RV and LV) of Langendorff-perfused rabbit hearts subjected to normothermic global no-flow ischemia, isoproterenol (30 nM) and pacing at the cycle length (CL) of either 300 ms or 200 ms. 2,3-butanedione monoxime (20 mM) was used to reduce motion artifact. Excitable area was measured in optical maps based on the criterion of the minimum time-derivative of the upstroke of the optical action potential. Decrease of the pacing CL from 300 to 200 ms dramatically accelerated loss of excitability in both RV and LV (Figure, p<0.0001). Treatment with IKNa blocker
R56865
significantly postponed frequency-dependent electrical failure (p<0.0001), the protective effect being larger in RV than in LV (see Figure). After 5 min of reperfusion,
R56865
treatment group also showed better recovery of excitability, effect being predominant in the LV in comparison to 200 ms CL group. This is the first study to show that IKNa activation can promote electrical failure under conditions mimicking VF-induced cardiac arrest.
Abstract 218: Interaction Between Lung Disease and Anti-Psychotic Drugs in Pulseless Electrical Activity
Authors: Teodorescu Carmen , Reinier Kyndaron , Uy-Evanado Audrey , Mariani Ronald , Chugh Harpriya , Gunson Karen , Jui Jonathan , Chugh Sumeet S
Published: April 2024

Introduction:
There has been a paradigm shift in manifestation of sudden cardiac arrest (SCA), with decreasing rates of ventricular fibrillation/tachycardia (VF/VT) and an increase in the proportion of pulseless electrical activity (PEA). To elucidate mechanisms, we further evaluated the relationship between PEA and pulmonary disease, which has consistently been reported in epidemiologic and clinical evaluations of this condition.

Methods:
Cases with PEA and VF/VT (age ≥ 18 years) were enrolled from a large ongoing population-based study of out-of-hospital SCA in the Northwestern US (pop approx. 1 million). The presenting arrhythmia was determined from review of first responder resuscitation reports. Detailed clinical history was obtained from medical records prior to SCA. Pearson’s
x
2
test and independent samples
t
-test were used for univariate comparisons. Logistic regression was used to evaluate significant factors associated with PEA vs. VF/VT.

Results:
Compared to VF/VT (n= 609), PEA cases (n= 346) were older, more likely to be female, were less likely to be witnessed, to arrest in public and have bystander CPR (p≤ 0.005). Survival to hospital discharge was lower in PEA than VF/VT (5% vs. 27%, p< 0.0001). History of COPD or asthma was more common in PEA (38% vs. 24%, p< 0.0001). Antipsychotic use was also more frequent in PEA group (13% vs. 4%, p< 0.0001). In a logistic regression model adjusting for demographic and arrest circumstances, there was significant interaction between COPD/asthma and antipsychotics (p= 0.04). Compared to subjects with no history of COPD/asthma and no antipsychotic use, subjects with COPD/asthma only had an increased odds of PEA [OR 1.8 (95% CI 1.3-2.5), while odds for subjects with only use of antipsychotics was 4.8 (95% CI 2.2-10.6). Subjects with both COPD/asthma and antipsychotics were also more likely to present with PEA [OR 2.6 (95% CI 1.2-5.7)].

Conclusion:
Susceptibility to PEA involves a significant interplay between pulmonary disease and use of antipsychotic drugs. These findings have potential implications for the ongoing mechanistic investigation of PEA, especially development of animal models.
Abstract 223: Failed Intubation Attempt During Emergency Department Resuscitation of Out-of-Hospital Cardiac Arrest Patient
Authors: Kim Joonghee , Kim Kyuseok , Kim Taeyun , Rhee Joong Eui , Kim You Hwan , Lee Jae Hyuk
Published: April 2024

Backgrounds:
Endotracheal intubation is a commonly used procedure to secure airway during emergency department (ED) resuscitation of out-of-hospital cardiac arrest (OHCA) patients. However, it can lead to many complications such as airway trauma or esophageal intubation. Currently, it is unknown whether failed intubation attempt has clinically significant impact on prognosis during resuscitation of OHCA patients in ED where multiple airway adjunct and many trained rescuers are available.

Methods:
An ED OHCA registry of a tertiary hospital extending from 2008 to 2012 were reviewed to identify non-traumatic OHCA patients who were resuscitated on ED arrival. Prehopsital and demographic factors and patient outcomes were retrieved from the registry. Number of failed intubation attempts was assessed from nurse-documented CPR records. Primary outcome was achievement of sustained return of spontaneous circulation (ROSC). Secondary outcomes were survival discharge and 6-month neurologic outcome.

Results:
512 non-traumatic OHCA patients with ED intubation attempt during resuscitation were included. Failed intubation attempt was present in 77 patients and there was no significant difference in demographic or prehospital factors between those with and without it. With failed intubation attempt, the unadjusted and adjusted odds ratios (ORs) for achieving sustained ROSC was 0.62 (95% confidence interval [CI], 0.38-1.01) and 0.51 (95% CI, 0.29-0.89), respectively. In a propensity-matched sample, the adjusted OR was 0.82 (95% CI, 0.69-0.97). However, no significant difference in long-term outcomes was found in any of the analyses.

Conclusion:
Failed intubation attempt in ED was an independent risk factor for resuscitation failure in ED OHCA patients.
Abstract 224: Modified Minimally Interrupted Cardiac Resuscitation Protocol and Outcomes After Out-of-Hospital Cardiac Arrest in a Metropolitan City
Authors: Kim Joo Yeong , Shin Sang Do , Song Koung Jun , Ha So Young , Lee Eui Jung
Published: April 2024

Introduction:
Prompt and minimal interruption of cardiac resuscitation (MICR) protocol includs more strict and continuous chest compression, delayed airway procedures, and team approach cardiopulmonary resuscitation (CPR) for minimal interruption of chest compression. However, it is unclear whether MICR is effective in an Asian EMS system with intermediate service level or not.

Objective:
This study aimed to determine whether the MICR protocol is associated with improved out-of-hospital cardiac arrest (OHCA) outcomes in a metropolitan city.

Methods:
This is a before- and after- EMS intervention trial. Data on patients with adult OHCA (18 years old and older) of cardiac etiology were from January 2011 to December 2012. The MICR protocol was implemented as a standardized field protocol in January 2011 and followed by a series of education and training for EMS providers. Education and training session composed of knowledge and skill sessions (four hours) was held in February and June 2012 for 50 and 70 EMS teams each. Outcome was prehospital return of spontaneous circulation and survival to discharge. Intervention group was defined as patients treated by 120 teams after training of the protocol and control group was patients treated by same EMS providers before training. A multivariable logistic regression analysis was used to compare outcomes between two groups adjusting for potential risks.

Results:
Total 622 cases in intervention group and 868 cases in control group were enrolled. Prehospital return of spontaneous circulation (ROSC) was 3.0% in control group and 6.1% in intervention group (p=0.004). Survival to discharge rate was 9.33% in control group and 11.3% in intervention group (p=0.225) . Adjusted odds ratio (95% confidence interval) of intervention compared with control group for prehospital ROSC and survival to discharge was not significant.

Conclusions:
The MICR protocol showed higher prehopital ROSC and survival to discharge rate than conventional CPR protocol in a metropolitan city but the adjusted model did not show better outcome. More intensive training to disseminate protocol among EMS providers is needed.
Abstract 241: Amplitude Spectrum Area as a Tool to Identify the Circulatory Phase of Ventricular Fibrillation
Authors: Ristagno Giuseppe , Quan Weilun , Silver Annemarie , Herken Ulrich , Bobrow Bentley
Published: April 2024

Background:
Ventricular fibrillation (VF) cardiac arrest (CA) is characterized by 3 time dependent phases: electrical (shorter than 4min), circulatory (4-10min), and metabolic (longer than 10min). These phases reflect the progressive increase of myocardial ischemia and suggest the potentially optimal treatment. During the electrical phase, immediate defibrillation is likely to be successful, while during the circulatory phase, the success of defibrillation diminishes without CPR. In the metabolic phase, there is low likelihood of successful resuscitation and probably a longer CPR interval prior to defibrillation is necessary. In the out-of-hospital (OH) setting, most patients may have passed the electrical phase when EMS arrives. Identification of the VF phase may therefore facilitate the proper CPR treatment. We used AMSA to determine if patients were in circulatory or in metabolic phase at EMS arrival.

Methods:
Data from an Utstein-compliant registry along with electronic ECG records were collected on consecutive adult OHCA patients treated by 2 EMS agencies over a 2 year period. Patients with bystander witnessed CA and with VF as initial CA rhythm were included (n=41). AMSA was calculated in earliest pause without compression artifacts, using a 2 sec ECG with a Tukey (0.2) FFT window. VF duration was calculated as the sum of the time interval from collapse to defibrillator on and the time interval from defibrillator on to first CPR interruption for defibrillation delivery.

Results:
VF duration ranged between 6.5 and 29.6 min (11.3+4.1 min), with a corresponding AMSA between 2.1 and 16.4 mV-Hz (9.4+4.2 mV-Hz). AMSA measured in the circulatory phase (N=19) was significantly higher than that in the metabolic phase (N=22) (8.14+3.17 vs. 5.98+2.88, p=0.03). Linear regression revealed that AMSA decreases by 0.22 mV-Hz for every min of VF. AMSA was able to predict circulatory phase with an accuracy of 0.7 in ROC area. An AMSA threshold of 10 mV-Hz was able to predict the circulatory phase with sensitivity of 32%, specificity of 95%, PPV of 86%, NPV of 62% and overall accuracy of 66%.

Conclusions:
AMSA is a good indicator of downtime in OHCA with initial rhythm of VF. AMSA could be used to identify VF phase and thereby suggest for the proper CPR intervention.
Abstract 246: Incidence and Outcomes of Rearrest Following Out-of-Hospital Cardiac Arrest
Authors: Salcido David D , Sundermann Matthew L , Koller Allison C , Menegazzi James J
Published: April 2024

Background:
Rearrest (RA) occurs when a patient experiences cardiac arrest after successfully achieving return of spontaneous circulation (ROSC). The incidence and outcomes of RA following out-of-hospital cardiac arrest (OHCA) have been estimated in limited local studies. We sought to investigate the incidence and outcomes of RA over a broad geographic area.

Methods:
This retrospective study was approved by the University of Pittsburgh Institutional Review Board. We obtained case data from EMS-treated, non-traumatic OHCA from the Resuscitation Outcomes Consortium, a multi-site clinical research network conducting population level surveillance of OHCA in 11 cities in the US and Canada. The study cohort comprised all OHCA cases surveilled between 2006 and 2008 at ROC sites and having prehospital ROSC. We used three methods to ascertain RA incidence among these cases: direct signal analysis, indirect cardiopulmonary resuscitation (CPR) process analysis, and emergency department arrival vital status. RA incidence was estimated as the proportion of cases with ROSC that experience RA. Regional RA estimates were compared with the Chi-Squared test. Multivariable logistic regression was used to assess the relationship between RA and survival to hospital discharge.

Results:
Out of 18,937 cases of EMS-assessed OHCA captured between 2006 and 2008, 11,456 (60.5%) cases were treated by EMS and 4,396 (38.4%) had prehospital ROSC. Of these, sufficient data were available for RA ascertainment in 3,253 cases, with 568 (17.5%) experiencing RA. Regional RA incidence varied significantly from 10.2% to 21.2% (p < 0.001). RA was significantly inversely associated with survival (OR: 0.19, 95%CI: 0.14 - 0.26).

Conclusions:
In this geographically broad and inferentially conservative analysis, RA occurred on average in 1 of every 6 successfully resuscitated patients, though incidence varied significantly across 10 sites in North America. RA was found to be inversely associated with survival to hospital discharge.
Abstract 247: Effect of Post Resuscitation Care Frequency on Outcome After Cardiac Arrest
Authors: Schober Andreas , Hochrieser Helene , Posch Martin , Schmutz Rene , Metnitz Philipp , Holzer Michael
Published: April 2024

Determination of the impact of the treatment frequency, hospital size and capability on mortality of patients admitted after cardiac arrest for post resuscitation care to different intensive care units in Austria.

Methods:
Prospectively recorded data from 242,588 adults consecutively admitted to 87 Austrian intensive care units over a period of 13 years (1998-2010) were analyzed retrospectively.

Results:
In total 5,857 patients had suffered cardiac arrest and were admitted to an intensive care unit for post resuscitation care. Observed hospital mortality was 15% in the non cardiac arrest cohort (36,460 non survivors) and 56% in the cardiac arrest cohort (3302 non survivors; p<0.0001). Patients treated in intensive care units with a high frequency of post resuscitation care generally had higher severity of illness. Intensive care units with a higher frequency of post resuscitation care showed improved risk adjusted mortality. The SAPS II adjusted, observed to expected mortality ratios (O/E-Ratios) in the three strata (less than <18; 18 to 26; more than 26 resuscitations per ICU per year) were 0.869 (95-%-confidence interval: 0.844 - 894), 0.876 (0.850 - 0.902) and 0.808 (0.784 - 0.833).

Conclusions:
Intensive care units, providing post resuscitation care at a high frequency, were associated with improved outcome. Establishing cardiac arrest care centers might be a reasonable step to improve outcome after cardiac arrest.
Abstract 251: Measuring the Association of CPR Quality Metrics and Intra-Arrest End-Tidal Carbon Dioxide
Authors: Sheak Kelsey , Wiebe Douglas J , Leary Marion , Abella Benjmain S
Published: April 2024

Background:
End-tidal carbon dioxide (ETCO
2
) is an indicator of blood flow during low-flow states such as during CPR delivery. Given that cardiac arrest survival is sensitive to CPR quality, ETCO2 might serve to guide CPR during clinical care. ETCO
2
has been shown to be a useful indicator of CPR quality in laboratory arrest models, however, there is a lack of clinical data assessing this relationship in humans.

Objectives:
To determine the association between quantitative CPR performance and intra-arrest ETCO2 in a time-based analysis of clinical resuscitation events.

Methods:
In this single center retrospective study we collected ETCO
2
data and time-synchronized CPR quality metrics using CPR-recording defibrillators (MRx QCPR, Philips Healthcare) during cardiac arrest events between 08/2007-06/2012. For each case, mean ETCO
2
for each 30 sec segment of CPR was calculated manually by averaging the peaks of each capnographic waveform. CPR 30 sec segments were divided into tertiles based on rate and depth, and combined to form nine groups representing combinations of CPR performance. A mixed-effect regression of mean ETCO
2
with the nine CPR combinations was performed using shallow depth and slow rate as the reference category.

Results:
Of the 54 arrest events with both CPR quality metrics and ETCO
2
waveform data, we extracted 992 30 sec blocks that had compression pauses < 5 sec. Deep compression depth coupled with a slow, medium or fast rate and a medium depth coupled with a fast rate produced statistically significant higher ETCO
2
values than the reference category (see figure).

Conclusions:
Greater compression rate and depth are associated with higher mean ETCO
2
during the same 30 sec period of time. This relationship suggests a physiologic response to CPR quality as detected via ETCO
2
measurement. The potential clinical use of ETCO2 to guide CPR requires further investigation.
Abstract 259: Available Prehospital Covariates Predict Coronary Ischemia as the Cause of Sudden Out-of-Hospital Cardiac Arrest Among Failed Resuscitations
Authors: Hartsell Sydney , McLaren Daryl , de la Presa Martin , Taillac Peter , Youngquist Scott T
Published: April 2024

Introduction:
Intra-arrest percutaneous coronary intervention (PCI) has been proposed to increase survivorship from sudden out-of-hospital cardiac arrest (OHCA) that fails prehospital resuscitation. Given costs and system constraints to intra-arrest PCI, the ability to predict coronary ischemia as the cause of arrest may be beneficial to guide its performance.

HYPOTHESIS:
We hypothesized that readily available prehospital information would predict coronary ischemia as the cause of OHCA amongst failed resuscitation attempts.

METHODS:
Review of medical examiner reports for adult victims of OHCA for whom prehospital resuscitation was attempted. Data was linked to prehospital data documenting Utstein variables and patient demographics. Logistic regression was performed to generate a predictive model for coronary ischemia as the cause of arrest.

Results:
119 autopsy reports were identified. Of these, 68 (57%) were terminated in the field, 51 (43%) in the ED. Males composed 77% of the sample. Mean age was 50+14 years. Coronary ischemia was determined to be causative in 50/119 (40%) of failed arrests. A logistic regression model that included shockable rhythm (OR 13, 95% CI 4-47), age (OR 2 per decade of life, 95% CI 2-4), and male gender (OR 6, 95% CI 1-32) demonstrated an area under the receiver-operating curve of 0.88 and correctly classified 76% of cases. Predictive probabilities derived from the model can be used to predict individual risk (Figure).

CONCLUSIONS:
In conclusion, the combination of an initial shockable rhythm, advanced age, and male gender are all highly predictive of acute coronary ischemia as the cause of OHCA.
Abstract 260: Automatic Shock Advisory Without Interrupting Chest Compression by Filtering Compression Artifact
Authors: Babaeizadeh Saeed
Published: April 2024

Background:
Both AHA and ERC Guidelines 2010 focus on minimizing “hands-off time” - the time interval a patient in cardiac arrest is not receiving chest compressions (CC). The primary device-related cause of CC interruption is automated ECG rhythm analysis for accurate shock advisory. The mechanical activity of CC produces artifact on the ECG waveform that most automated ECG analysis programs cannot fully differentiate from the patient’s inherent ECG morphology. Furthermore, clinicians observing an ECG waveform on the defibrillator’s display cannot see the patient’s underlying rhythm through the electrical noise created by CC, forcing an interruption to CC for rhythm assessment.

Objective:
Improving the performance of ECG analysis programs by filtering artifacts due to CC in out of hospital cardiac arrest (OHCA) patients.

Methods:
Recordings from 175 OHCA patients collected for a separate study using Laerdal HeartStart 4000 defibrillators in 6 ambulances in 3 European regions between March 2002 and October 2003. The transition times from CC to hands-off were marked. Assuming no rhythm change within a few seconds around the transition time, experts selected 1378 4.5-second ECG segments with CC artifact, and the same number without the artifact. Each category included 340 shockable ventricular fibrillation, 342 asystole, 646 pulseless electrical activity, and 50 pulsatile rhythms. A two-step process was designed to filter the CC artifact prior to the analysis by the shock advisory algorithm. By analyzing both ECG and thoracic impedance waveforms the fundamental frequency of CC was found, to then be filtered along with all its harmonics using a comb filter.

Results:
Defining a positive event as shock advice for shockable rhythm, the shock advisory algorithm achieved sensitivity of 97% and specificity of 99% when no CC was being performed. However during CC both sensitivity and specificity dropped to 63% and 91% respectively. Filtering the CC artifact increased the sensitivity back up to 89% at the expense of slightly reducing the specificity to 90%.

Conclusion:
It is possible to improve the performance of shock advisory algorithms during CC by filtering the CC artifact. However additional techniques may be needed to achieve accuracy high enough for practical use.
Abstract 261: Correction for Body Displacement for Accurate Delivery of Chest Compressions: Accuracy of the Truecpr Device on a Soft Mattress
Authors: Beesems Stefanie G , Koster Rudolph W
Published: April 2024

Objective:
Accelerometer based chest compression feedback devices overestimate compression depth by not accounting for a soft surface below the victim. TrueCPR, a new real-time feedback device, provides visual feedback on compression depth, based on measured changes in magnetic field strength between a backpad and a chestpad. We determined accuracy of that method on a calibrated test bench and on a manikin on a soft surface.

Methods:
First, we used a calibrated, computerized drill press compressing a Laerdal Resusci Anne SkillReporter manikin on a firm surface to verify calibration of its compression depth measurement, and to measure accuracy of the TrueCPR device.

Then, we compared measurements of two feedback devices (TrueCPR and a sternum-only accelerometer) on a standard inflatable hospital mattress. Thirty manual chest compressions were given with feedback of TrueCPR or the accelerometer, to achieve the recommended depth of 50-60 mm and compared with the compression depth measured by the manikin.

Results:
Compared to the drill press, the manikin measured compression depth with error <1 mm for depths below 55 mm and with 1-2 mm underestimation above 55mm. TrueCPR showed a systematic underestimation of 3-4 mm on a hard surface.

On the mattress, TrueCPR showed an underestimation of 2-4 mm, where the accelerometer showed an overestimation of 17-23 mm (figure). A compression depth in the recommended range was achieved with TrueCPR in 23 of 30 compressions and with the accelerometer in 2 of 30 compressions.

Conclusion:
TrueCPR measures depth independent of the stiffness of the surface upon which the CPR is being performed with a constant underestimation of <4 mm. A sternum-only accelerometer substantially overestimates depth when performing CPR on a soft surface. Correction for body displacement on a soft surface is essential for accurate delivery of chest compressions within the recommended depth range.
Abstract 263: Comparison of Megacode Assessment Following an Enhanced Heartcode ACLS Course versus a Standard Full ACLS Provider Course
Authors: Bortner Tammi , Sinz Elizabeth
Published: April 2024

Background:
The AHA endorses 2 instructional methods for Advanced Cardiac Life Support (ACLS): 1) traditional, live, classroom course with skills practice and training scenarios, or 2) web-based, self-paced program with interactive skills practice and testing using avatars (Heartcode ACLS). We compared Mega-code performance of students enrolled in live vs. enhanced online full provider courses.

Methods:
Students enrolled in ACLS were invited to participate, self-selecting their preferred instructional method (online vs live). Four courses were divided into live and online groups. Students choosing the online course also participated in a one-hour megacode practice. Participants were blended for megacode skills testing given by instructors unaware of students’ learning method. Other assessments by instructors included skill level (1-low, 4-high) and group rank (best to worst).

Results:
A total of 101 students agreed to participate and 77 (44 live, 33 online) were included (5 physicians, 43 nurses, 14 medical students, and 14 other allied health professionals). 10 had current cards, (7-live, 3-online), 27 had expired cards (17-live,10-online), and 40 had no prior card (20-live, 20-online). The remediation rate was not sig. different for live vs. online groups (4.55% vs 15.15%, p=0.22), and mean skill level was not sig. different for live vs. online (3.32 vs 3.06, p=0.25). Mean and median ranks were better for students in live vs the online study (2.74 vs 3.53, 2 vs 4, p=0.044). Likewise the % ranked in the top of their group was higher in the live (67%) vs. the online group (45%) (p=0.054). There was no sig. difference in the % with a prior class between the 2 arms.

Discussion:
Although Heartcode ACLS was designed as an ACLS renewal course, some centers and students prefer an online method to complete the full ACLS course requirement. Due to concerns that an online course might not prepare students for the Megacode test or actual arrests, many centers opt not to use the Heartcode product. Our data indicate that with a single practice session, Megacode performance is comparable for those in a full provider course vs those completing Heartcode ACLS. The online course allows students to perform Megacode skills adequately after only 2-3 hours in a testing center, vs 1.5 days.
Abstract 274: Pulse Detection with Photoplethysmography (PPG) in Hemodynamic Instability
Authors: Hubner Pia , Russel James K , Schober Andreas , Wallmueller Christian , Sterz Fritz
Published: April 2024

Pulse detection could guide therapy but noninvasive methods accurate in emergencies remain elusive. We investigated feasibility of noninvasive pulse detection in hemodynamic instability in an emergency department.

Hypothesis:
Pulse detection in hemodynamic instability may be feasible using PPG.

Methods:
An algorithm detected pulses in signals from commercial oximeters (NICO, Oxypleth - Philips) applied to a peripheral (fingertip) and two central (nasal septum, ear pinna) sites and pressure catheters in radial arteries (Intellivue - Philips). Heart rates from average interpulse intervals in 3 s periods, were updated each second. Data was classified by systolic pressure. Rates from each oximeter site were compared to the arterial rate.

Results:
We recorded over 140 hours of PPG signals from 30 patients during CPR, post-resuscitation care, shock and syncope from October 2012 to May 2013. Technical difficulties excluded 3 patients from analysis.

Even weak pulses were evident in PPG waveforms (figure).

Pulse detection was accurate for all sensors at all sites and pressures (table). Central sites tended to be more accurate than the finger at low pressures.

Conclusions:
A noninvasive pulse detector using PPG appears feasible and may be useful in initial patient assessment, during pauses in CPR and during chest compressions.
Abstract 277: Neurologically Intact Survival and Time Interval From Collapse to Return of Spontaneous Circulation for Out-of-Hospital Non-Shockable Cardiac Arrest; A Comparison of Pulseless Electrical Activity and Asystole
Authors: Nagao Ken , Kasai Asuka , Tachibana Eizo , Yonemoto Naohiro , Takayama Morimasa , Nonogi Hiroshi , Shirai Shinichi , Kimura Takeshi
Published: April 2024

Background:
Early achievement of return of spontaneous circulation (ROSC) after cardiac arrest is critical to neurologically intact survival, but few data are available concerning this interval comparing pulseless electrical activity (PEA) and asystole.

Methods:
From the All-Japan Utstein Registry, a prospective, nationwide, population-based registry of out-of-hospital cardiac arrest (OHCA) between 2005 and 2011, we included adult patients who received resuscitation care after witnessed OHCA due to non-shockable arrest and whose ROSC was achieved before hospital arrival. We divided study patients into two groups according to the initial cardiac arrest rhythm and evaluated the relationship between the collapse-to-ROSC interval and favorable neurological outcome 30 days after cardiac arrest.

Results:
Of the 31,845 patients who achieved ROSC after witnessed OHCA, 12,905 (40.8%) achieved ROSC after PEA and 7,259 (22.8%) after asystole. The PEA group had a significantly shorter collapse-to-ROSC interval compared with the asystole group (18.9±11.6 vs. 25.3±12.6 minutes, p<0.0001) and a significantly higher frequency of 30-day favorable neurological outcome (15.5% vs. 7.1%, p<0.0001). After adjustment for resuscitation, the likelihood of favorable neurological outcome decreased for every 1 minute increment in the collapse-to-ROSC interval in the PEA group (adjusted OR; 0.94, 95% CI, 0.93 to 0.95) and in the asystole group (adjusted OR; 0.93, 95% CI, 0.91 to 0.94). Non-linear regression analysis showed that frequency of favorable neurological outcome decreased from 33.6% to 0% for every minute that passed between collapse and ROSC in the PEA group and from 29.2% to 0% in the asystole group. For favorable neurological outcome, a collapse-to-ROSC interval of 56.5 minutes had a sensitivity of 100% with a negative predictive value of 99.6% in the PEA group, and that of 56.5 minutes had a sensitivity of 100% with a negative predictive value of 99.1% in the asystole group.

Conclusion:
In patients achieving ROSC after witnessed OHCA, PEA patients had a significantly higher favorable neurological outcome than asystole patients. However, the interval in which resuscitation efforts must be sustained is similar for both arrest rhythms.
Abstract 289: Geographic Factors Associated With High Risk for Out-Of Hospital Cardiac Arrests and Provision of Bystander Cardio-Pulmonary Resuscitation in Singapore
Authors: Ong Marcus Eng Hock , Wah Win , Earnest Arul , Hsu Li Yang , Ng Yih Yng , Leong Benjamin Sieu-Hon , Goh E Shaun , Gan Han Nee , Tham Sharon Lai Peng , Charles Rabind A , Foo David Chee Guan
Published: April 2024

Objectives:
The objectives were to investigate association of individual and population characteristics in the provision of Bystander Cardio-Pulmonary Resuscitation (BCPR) among OHCA cases happened at home and identify high risk residential areas with low risk of BCPR and high risk of Out-of-Hospital Cardiac Arrest (OHCA) at the Development Guide Plan (DGP) census tract levels in Singapore.

Methods:
This was a retrospective, secondary analysis of two prospectively collected registries in Singapore from 2001 to 2011. We used Bayesian conditional autoregressive spatial models to examine predictors at the DGP level and to calculate smoothed relative risk (RR) to identify high risk clusters. We used multi-level mixed-effects logistic regression models to examine the independent effects of individual and neighborhood factors.

Results:
We found a total of 3942 OHCA with BCPR rates of 20.3% and 3578 cases eligible for BCPR. OHCA cases receiving BCPR at home were more likely to be witnessed (OR=1.69, 95%CI=1.34-2.12), younger (OR=0.98, 95%CI=0.97-0.98), presumed cardiac etiology (OR=1.48, 95%CI=1.14-1.91) and had longer response time (OR=1.04, 95%CI=1.01-1.06). After adjusting for individual arrest characteristics, an increased risk of provision of BCPR was significantly related to higher proportion of household size five and above at areal level (RR=1.02, 95% Credible Interval=1.01-1.04). We identified 10 high risk residential areas.

Conclusion:
We found differences in risk of receiving BCPR in different geographic areas. This study supported that neighborhood household size could play a significant role in the provision of BCPR and occurrence of high risk areas. Those high risk residential areas identified could be possible sites to target community based interventions (CPR training and public access defibrillation).
Abstract 291: Intestinal Microcirculatory Alterations in a Rat Model of Cardiac Arrest and Resuscitation
Authors: Qian Jie , Xu Jiefeng , Yang Zhengfei , Hu Xianwen , Cahoon Jena , Sun Shijie , Tang Wanchun
Published: April 2024

Introduction:
Abnormalities in intestinal microvascular blood flow are of increasing interest during the post-resuscitation phase following cardiac arrest because of the critical role attributed to the intestine in the pathogenesis of systemic inflammatory response, which potentially further aggravate post-resuscitation myocardial and cerebral dysfunction. The present study investigated post-resuscitation mesenteric microcirculatory dysfunctions in a rat model of cardiac arrest and resuscitation.

Methods:
Eight Sprague-Dawley rats were divided into two groups: 1) VF8+PC8 group: 8 mins of untreated VF followed by 8 mins of CPR and defibrillation (n=5); 2) sham control: animals only underwent surgical procedure (n=3). A laparotomy was performed to expose a segment of the jejunum. Twenty-second clips of the mesenteric microcirculation were captured with the sidestream dark field (SDF) video microscope at three locations at baseline and at 1, 2, 4, 6, 8 hours after the return of spontaneous circulation (ROSC). Mesenteric microcirculatory blood flow was quantified off-line by determining the microcirculatory flow index (MFI).

Results:
MFIs were significantly reduced 1 hour after ROSC and gradually recovered until it reached a peak at the 6th hour. This was followed by a remarkable decrease at the 8th hour. Compared with control group, MFIs reductions in the VF8+PC8 group were statistically significant (p<0.01) at all time points except for 6 hours after ROSC.

Conclusion:
There was a significant reduction in mesenteric microcirculatory blood flow following successful resuscitation from cardiac arrest.
Abstract 292: Time Course of Epinephrine Administration During Cardiac Arrest Shows Transient Increase in Aortic Pressure at the Cost of Persistent Decrease in Carotid Flow
Authors: Ramadeen Andrew , Hu Xudong , Tsui Albert K , Hare Gregory M , Dorian Paul
Published: April 2024

Epinephrine is routinely used during treatment of cardiac arrest. Administration may improve immediate resuscitation at the cost of long term survival. We hypothesized that epinephrine transiently increases aortic pressure, but decreases blood flow to the brain during cardiopulmonary resuscitation (CPR).

Methods:
Six anesthetized Yorkshire pigs (31±4 kg) underwent 1 minute of untreated ventricular fibrillation (VF), followed by 9 minutes of guideline based CPR with mechanical compressions, then defibrillation. Epinephrine (1 mg IV) was administered 1-3 times per pig (median 2.5) at ≥3 minute intervals. Hemodynamic parameters were measured continuously with a micromanometer in the abdominal aorta and a perivascular flow probe around the carotid artery.

Results:
After 10 minutes of VF, 5 of 6 pigs were successfully defibrillated, but all 5 became asystolic or lacked pulsatile aortic pressure 30 minutes after defibrillation. During CPR prior to epinephrine injection, aortic systolic and diastolic pressures were 72±26 and 17±3 mmHg respectively, coronary perfusion pressure was 15±5 mmHg and antegrade carotid blood flow was 141±77 mL/min. Epinephrine produced a repeatable, transient effect on both aortic pressure and carotid blood flow (see Table). Aortic systolic and diastolic pressures increased above pre-injection values with peak pressures reached approximately 80 seconds after injection and stabilizing after 180 seconds. Carotid flow decreased below pre-injection values with nadir flow reached approximately 80 seconds after injection, and remained below baseline for 100 additional seconds or longer.

Conclusions:
The effect of epinephrine on hemodynamics during CPR is not consistent over time. Epinephrine produces differential effects on aortic pressure and carotid flow. Although epinephrine may transiently improve coronary perfusion, it may do so at the cost of brain perfusion.
Abstract 295: After 2010 Guidelines Less Fear and More CPR
Authors: Savastano Simone , Vanni Vincenzo , Langord Karen
Published: April 2024

Introduction:
Prompt and good quality cardio-pulmonary resuscitation (CPR) is fundamental for cardiac arrest victims survival. The percentage of bystander CPR is generally low and one of the reasons are the fears of the rescuers. With 2010 guidelines, CAB replaced the ABC sequence and hands only CPR was recommended for untrained lay rescuers. The aim of our study was to evaluate the effects of these changes on lay rescuers’ willingness to perform CPR on an unknown adult or child, and on their fears.

Materials and methods:
At the end of each CPR course for lay rescuers we distributed a rigorously anonymous questionnaire written either in Italian or in English exploring the willingness to perform CPR on an adult or on a child and the related main fears (infectious disease, competency, causing damage, legal complications, and general fear). Each person received only one questionnaire and attended only one course.

Results:
1374 questionnaires have been collected (82.1% males, 86.4% Italians, high school 63.2%, higher education degree 23.8%; 1000 before 2010: group A and 374 after 2011: group B). In the general population a significant difference between the percentage of subjects who would perform CPR on an adult or on a child has been demonstrated (88.4% vs 75.3% respectively p<0.001). Moreover the willingness to perform adult CPR was significantly higher in group B than group A (94.4% vs 86,2% p<0.001). A nearly significant trend has been demonstrated between group B and A (79% vs 74% p=0.05) for pediatric CPR. Comparing groups A and B on the fears of performing adult CPR we observed a significant reduction in the fear of legal complications (1.8% vs 0.3% p=0.03) and of general fear (6.8% vs 3.2% p=0.02). In the pediatric case the only significant reduction observed was of the competency fear (7.8% vs 2.1% p<0.001). The expected reduction in the fear of infectious diseases has not been demonstrated neither for adult CPR (1.4% vs 0.5% p=0.26) nor for pediatric CPR (0.9% vs 0.3% p=0.31)

Conclusions:
After 2010, the willingness of lay rescuers to perform adult CPR has significantly increased due to a significant reduction of rescuers’ fears. On the basis of these results the new guidelines are thought to increase survival also by increasing incidences of bystanders CPR.
Abstract 297: Performance-Improvement Based Resuscitation Training Decreases Cardiopulmonary Arrests and Improves Survival
Authors: Sell Rebecca E , Carroll Karen , Moore Heather M , Davis Daniel P
Published: April 2024

Background:
Despite recent advances in cardiopulmonary arrest resuscitation, survival remains poor. Traditional training models have difficulty achieving and maintaining resuscitation competency. The UCSD Advanced Resuscitation Training (ART) Program, a performance-improvement based resuscitation program, has led to a sustained increase in survival to discharge after inpatient cardiac arrest from 21% to 45%.

Objective:
To evaluate the effectiveness of the ART program on survival after inpatient cardiac arrest and hospital mortality at the Veterans’ Affairs (VA) Hospital System in San Diego.

Methods:
This was a prospective, observational study conducted in an urban, university-affiliated VA. All inpatient cardiopulmonary arrest (CPA) victims without an active "Do Not Attempt Resuscitation" order from October 2006 to June 2012 were included. The ART program was implemented in Summer 2007 and included a unique treatment algorithm constructed around the capabilities of our providers and resuscitation equipment, a rapid response team, a training program with flexible format and content including early recognition concepts, and a comprehensive approach to performance improvement feeding directly back into training. Our inpatient resuscitation registry and electronic patient care records were used to quantify arrest rates and survival-to-hospital discharge yearly after ART program implementation.

Results:
A total of 476 CPAs were included (176 within the Intensive Care Unit (ICU) and Emergency Department (ED), and 300 outside of the ICU/ED). Arrest incidence decreased yearly from an initial rate of 10.3 to 2.7 CPA per 1,000 patient discharges in non-ICU inpatient units. Survival-to-discharge rates at the VA were comparable to those documented at UCSD (44% versus 45%, p=NS).

Conclusions:
Implementation of the ART program at the Veterans Affairs Medical Center resulted in a decrease in the incidence of CPA with high survival-to-discharge rates.