Initial Cardiac Arrest Rhythm Research Articles

Abstract 19427: Epidemiology and Outcomes of Out-of-hospital Cardiac Arrest in Qatar

Aim: There is a scarcity of population based studies on out-of-hospital cardiac arrest (OHCA) in the Middle East and the wider Asian region. This study describes the Epidemiology and outcomes of OHCA in Qatar, a Middle Eastern country. Methods: Data was extracted retrospectively from a national registry on all adult cardiac origin OHCA patients attended by Emergency Medical Services (EMS) in Qatar, from June 2012 - May 2013. Results: The annual crude incidence rate of cardiac origin OHCA attended by EMS was 23.5 per 100,000. The age-sex standardized incidence rate was 87.83 per 100,000 population. The annual sex-standardized incidence rate for males and females was 91.5 and 84.25 per 100,000 population respectively. Of 447 adult, cardiac origin OHCA patients included in the final analysis, most were male (n=360, 80.5%) with median age of 51 years (IQR = 39-66). Frequently observed nationalities of OHCA cases were Qatari (n=89, 19.9%), Indian (n=74, 16.6%) and Nepalese (n=52, 11.6%). Common initial cardiac arrest rhythms were asystole (n=301, 67.3%), ventricular fibrillation (n=82, 18.3%) and pulseless electrical activity (n=49, 11%). OHCA was unwitnessed (n=220, 49%) in nearly half of the cases while bystanders witnessed it in 170 (38%) patients. Bystander CPR was carried out in 92 (20.6%) of the cases. Of 187 (41.8%) patients who were given shocks, bystander defibrillation was delivered to 12 (2.7%) patients. Prehospital outcomes; 332 (74.3%) patients did not achieve return of spontaneous circulation (ROSC), 40 (8.9%) patients achieved unsustainable ROSC, 58 (13%) achieved ROSC till Emergency department (ED) handover and 5 patients achieved ROSC but rearrested again before reaching ED. Survival to hospital discharge occurred in 38 (8.5%) patients. Neurological outcomes were assessed utilizing Cerebral Performance Category [CPC] scores with a favorable CPC score of 1-2 at discharge in 27 (6%) patients, while 11 (2.5%) patients had a poor CPC score of 3-4. Of those with CPC score 1-2 at hospital discharge, 59% and 26% had CPC score 1-2, at 1 and 3 years follow-up respectively. Overall survival was 9.7%. Conclusion: Standardized rates are comparable to western countries, there are significant opportunities to improve outcomes, including better bystander CPR.

Abstract 75: Ventricular Fibrillation in Cardiac Arrest with Nonshockable Initial Rhythm

The initial shockable rhythm in cardiac arrest is a well known factor of good prognosis. Little is known about the influence of the onset of ventricular fibrillation during resuscitation at cardiac arrest whose initial rhythm was non-shockable. Methods: Retrospective analysis of a continuous registry of out-of-hospital cardiac arrest (OHCA) Inclusion criteria, all consecutive patients suffering OHCA attended by emergency teams in Andalusia, Spain. Period January 2008 - December 2012. Results: 5067 patients were included. According to the initial cardiac arrest rhythm 1038 (20.5%) cases presented initial shockable rhythm (SR) and 4029 (79.5%) with non-shockable initial rhythm (NSR). Of these patients 150 (3%) reported one or more episodes of ventricular fibrillation during resuscitation (NSRVF). The main clinical characteristics of these three groups are shown in Table 1. Variables associated with good neurological status at hospital discharge are shown in Table 2. Conclusions: NSRVF patients present higher survival with good neurological status than NSR patients. These patients may represent a third prognostic group in cardiac arrest with a survival rate between shockable and non-shockable initial rhythms. Table 1. Clinical data of patients regarding rhythm of cardiac arrest Table 2. Variables associated with good neurological status at discharge (CPC 1-2 ) SD: Standard deviation. IQR: Interquartile range. OR: Odds Ratio. CI: Confidence Interval. ET: Emergency Team. VF: Ventricular Fibrillation. CPR: Cardiopulmonary resuscitation. CPC: Cerebral Perfomance Category. ROSC: Return of spontaneous circulation

Outcomes following out-of-hospital cardiac arrest with an initial cardiac rhythm of asystole or pulseless electrical activity in Victoria, Australia

BackgroundWhile internationally reported survival from out-of-hospital cardiac arrest (OHCA) is improving, much of the increase is being observed in patients presenting to emergency medical services (EMS) in shockable rhythms. The purpose of this study was to assess survival and 12-month functional recovery in patients presenting to EMS in asystole or pulseless electrical activity (PEA). MethodsThe Victorian Ambulance Cardiac Arrest Registry was searched for adult OHCA patients presenting in non-shockable rhythms in Victoria, Australia between 1st July 2003 and 30th June 2013. We excluded patients defibrillated prior to EMS arrival and arrests witnessed by EMS. Twelve-month quality-of-life interviews were conducted on survivors who arrested between 1st January 2010 and 31st December 2012. The main outcome measures were survival to hospital discharge and 12-month functional recovery measured by the Extended Glasgow Outcome Scale (GOSE). ResultsA total of 38,378 non-shockable OHCA attended by EMS were included, of which 88.0% were asystole and 11.6% were PEA. Of the patients receiving resuscitation, survival to hospital discharge was 1.1% for asystole and 5.9% for PEA (p<0.001), with no significant improvement observed over the 10 year study period. In survivors with 12-month follow-up data, the combined rate of death, vegetative state or lower severe disability was 66.7% (95% CI 41.0–80.0%) for asystole and 44.7% (95% CI 30.2–59.9%) for PEA. ConclusionSurvival outcomes following OHCA with initial rhythms of asystole or PEA did not improve over the 10-year study period. Our findings indicate high rates of death within 12 months, and unfavourable functional recovery for survivors.

Treatment and Outcomes of ST Segment Elevation Myocardial Infarction and Out-of-Hospital Cardiac Arrest in a Regionalized System of Care Based on Presence or Absence of Initial Shockable Cardiac Arrest Rhythm

The aim of this study was to evaluate the treatment and outcomes of patients with ST-segment elevation myocardial infarctions complicated by out-of-hospital cardiac arrest in a regional system of care. In this retrospective study, the effect of the absence of an initial shockable arrest rhythm was analyzed. The primary end point of survival with good neurologic outcome in patients with and without an initial shockable arrest rhythm was adjusted for age, witnessed arrest, bystander cardiopulmonary resuscitation, and treatment with therapeutic hypothermia and percutaneous coronary intervention. One-hundred sixty-eight of 348 patients (49%) survived to hospital discharge. Patients with a shockable initial rhythm were more likely to receive therapeutic hypothermia (48% vs 37%, risk ratio 1.2, 95% confidence interval [CI] 1.0 to 1.5) and to be treated in the cardiac catheterization laboratory (80% vs 43%, risk ratio 2.8, 95% CI 2.0 to 3.8). The likelihood of survival with good neurologic outcome in patients with a shockable initial rhythm compared with those presenting without a shockable rhythm was 4.8 (95% CI 2.7 to 8.7). In patients who underwent percutaneous coronary intervention, the likelihood of survival with good neurologic outcome was higher (risk ratio 2.7, 95% CI 1.1 to 6.8) in those with a shockable rhythm. In conclusion, the absence of an initial shockable rhythm in patients with ST-segment elevation myocardial infarctions plus out-of-hospital cardiac arrest is associated with significantly worse survival and neurologic outcome. These differences persist despite application of therapies including therapeutic hypothermia and percutaneous coronary intervention within a regionalized system of care.

Abstract 120: Outcomes of Out-of-Hospital Cardiac Arrest in Children

Background: As pediatric out-of-hospital cardiac arrest (OHCA) occurs infrequently, little is known about survival outcomes in children. We examined whether OHCA survival in children differed by patients’ age, sex, and race, as well as recent survival trends. Methods: Within the Cardiac Arrest Registry to Enhance Survival (CARES), a prospective U.S. OHCA registry encompassing 64 million residents, we identified patients less than 18 years of age with an OHCA from October, 2005 to December, 2012. We examined whether survival differed by patients’ age (≤1 year, 1-8 years, &gt;8 years), sex, race, and initial cardiac arrest rhythm, using modified Poisson regression, adjusted for patient characteristics. Similarly, we examined trends in survival, with years 2005-7 as the reference. Results: A total of 1,412 patients with an OHCA were identified, of which 67 (4.7%) were infants, 918 (65.0%) were younger children, and 427 (30.2%) older children. Sixty percent of the study population was male and 33.4% were black. The vast majority of arrests involved a non-shockable rhythm, with only 9.2% of patients having a first documented rhythm of ventricular tachycardia (VT) or ventricular fibrillation (VF). Overall, 103 (7.3%) patients survived to hospital discharge. Of those with non-shockable rhythms (asystole, pulseless electrical activity, and unknown, non-shockable rhythms), 4.4% survived to discharge compared with a survival of 36.2% in those with VT or VF (P&lt;0.001). After adjustment for patient characteristics, children 1-8 years of age were less likely to survive to hospital discharge compared with children &gt;8 years of age (rate ratio [RR]: 0.52; 95% confidence interval [CI]: 0.34, 0.82). In addition, OHCAs due to VT or VF were associated with improved survival (RR 6.67; 95% CI 4.35, 10.23). In contrast, there were no differences in survival by sex or race. Additionally, no temporal trends in survival were observed (p=0.47). Conclusion: In a large, national registry of pediatric OHCA, we found no disparities in survival by patients’ sex, race, or year of arrest, although survival was lower in young children and those with non-shockable cardiac arrest rhythms.

Relation of Smoking Status to Outcomes After Cardiopulmonary Resuscitation for In-Hospital Cardiac Arrest

In-hospital cardiac arrest (IHCA) is common and is associated with poor prognosis. Data on the effect of smoking on outcomes after IHCA are limited. We analyzed the Nationwide Inpatient Sample databases from 2003 to 2011 for all patients aged≥18 years who underwent cardiopulmonary resuscitation (CPR) for IHCA to examine the differences in survival to hospital discharge and neurologic status between smokers and nonsmokers. Of the 838,464 patients with CPR for IHCA, 116,569 patients (13.9%) were smokers. Smokers were more likely to be younger, Caucasian, and male. They had a greater prevalence of dyslipidemia, coronary artery disease, hypertension, chronic pulmonary disease, obesity, and peripheral vascular disease. Atrial fibrillation, heart failure, and diabetes mellitus with complications were less prevalent in smokers. Smokers were more likely to have a primary diagnosis of acute myocardial infarction (14.8% vs 9.1%, p<0.001) and ventricular tachycardia or ventricular fibrillation as the initial cardiac arrest rhythm (24.3% vs 20.5%, p<0.001). Smokers had a higher rate of survival to hospital discharge compared with nonsmokers (28.2% vs 24.1%, adjusted odds ratio 1.06, 95% confidence interval 1.05 to 1.08, p<0.001). Smokers were less likely to have a poor neurologic status after IHCA compared with nonsmokers (3.5% vs 3.9%, adjusted odds ratio 0.92, 95% confidence interval 0.89 to 0.95, p<0.001). In conclusion, among patients aged ≥18 years who underwent CPR for IHCA, we observed a higher rate of survival in smokers than nonsmokers-consistent with the "smoker's paradox." Smokers were also less likely to have a poor neurologic status after IHCA.

Most Important Outcomes Research Papers on Cardiac Arrest and Cardiopulmonary Resuscitation

Cardiac arrest is a common and treatable cause of death and disability. Each year ≈424 000 people experience emergency medical services (EMS)-assessed out-of-hospital cardiac arrest (OHCA) in the United States.1 The actual burden of OHCA is likely significantly higher because a substantial number go unassessed. In a prospective analysis of deaths in a US county, 5.6% of annual mortality was attributable to cardiac arrest.2 Many patients who suffer OHCA do not receive prompt cardiopulmonary resuscitation (CPR). Among those who receive CPR, a large number do not survive because of an inability to restore spontaneous circulation, or anoxic cerebral injury even after restoration of circulation. Nevertheless, when timely interventions are provided, a small proportion of patients (10.4% of all EMS-treated OHCA) recover to resume normal lives. The key therapeutic interventions that make the difference between life and death, metaphorically characterized as the 5 links in a chain of survival by the American Heart Association, include: (1) immediate recognition of cardiac arrest and activation of the EMS, (2) early CPR with emphasis on chest compression, (3) rapid defibrillation, (4) effective advanced life support, and (5) integrated postcardiac arrest care.3 Resuscitation science has undergone major advances since the origins of modern CPR >50 years ago.4 The field continues to be dynamic with emergence of new therapies such as therapeutic hypothermia5 and improvements in systems of care. However, many questions remain on issues such as optimum compression rate, efficacy of chest compression only CPR (CCCPR), dispatcher-assisted CPR, and benefits of postresuscitation measures such as hypothermia. A critical challenge also lies in the translation of resuscitation science into practice. To improve outcomes, each of the links in the chain of survival needs to be executed promptly and effectively. There remain several lacunae, which need to be overcome to develop an …

Using risk prediction tools in survivors of in-hospital cardiac arrest.

In-hospital cardiac arrests are common and associated with poor outcomes. Predicting the likelihood of favorable neurological survival following resuscitation from an in-hospital cardiac arrest could provide important information for physicians and families. In this article, we review the literature regarding predictors of survival following in-hospital cardiac arrest. Specifically, we describe the Cardiac Arrest Survival Postresuscitation In-hospital (CASPRI) score that was recently developed and validated using data from the Get With the Guidelines-Resuscitation registry. The CASPRI score includes 11 predictor variables: age, initial cardiac arrest rhythm, defibrillation time, baseline neurological status, duration of resuscitation, mechanical ventilation, renal insufficiency, hepatic insufficiency, sepsis, malignancy, and hypotension. The score is simple to use at the bedside, has excellent discrimination and calibration, and provides robust estimates of the probability of favorable neurological survival after an in-hospital cardiac arrest. Thus, CASPRI may be valuable in establishing expectations by physicians and families in the critical period after these high-risk events.

Mean initial cerebral saturation and time to start advanced life support in out-of-hospital cardiac arrest: are they correlated?

During advanced life support (ALS) it is still impossible to predict return of spontaneous circulation (ROSC) or outcome. Cerebral saturation (rSO2) measurements with near-infrared spectroscopy can be used in cardiac arrest circumstances and could play a role in predicting ROSC or neurologic outcome [1]. It is known that an initial rhythm of asystole and a long no/low-flow time has a worse outcome. We measured rSO2 during ALS in out-of hospital cardiac arrest (OHCA) patients and compared the mean rSO2 during the first minute with the time between the emergency call (EC) and start of ALS.

Abstract 241: Amplitude Spectrum Area as a Tool to Identify the Circulatory Phase of Ventricular Fibrillation

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 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

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&lt;0.0001) and a significantly higher frequency of 30-day favorable neurological outcome (15.5% vs. 7.1%, p&lt;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.

Effectiveness of automated external defibrillation on survival outcomes among adult patients after in-hospital cardiac arrest: a systematic review

Background Cardiac arrest is defined as cessation of cardiac mechanical activity. Chain of was introduced in 1991 to improve survival after sudden cardiac arrest. Earlier defibrillation by an automated external defibrillator (AED) saves lives and improves the odds of survival for patients who suffer a sudden cardiac arrest outside the hospital. However, its role in a hospital setting has received conflicting results. Objectives The objective of this review was to identify the effectiveness of automated external defibrillation achieving the return of spontaneous circulation and survival to hospital discharge in adult patients after an in-hospital cardiac arrest. Inclusion criteria Types of participants The participants were 18 years old and above and suffering from sudden cardiac arrest in the hospital setting. Type of intervention The intervention of interest was use of an automated external cardiac defibrillator operated by trained healthcare professionals. Types of studies This review included any experimental study design including randomized controlled trials, non-randomized controlled trials, and quasi-experimental designs, including before and after studies. Types of outcomes The outcome measures were initial cardiac arrest rhythms, number of patients with a spontaneous return of circulation for at least 20 minutes during resuscitation, and number of patients surviving to hospital discharge. Search strategy The search strategy aimed to find both published and unpublished studies in ten databases from 2001 to 2012. Namely Medline, CINAHL, Embase, Web of Knowledge, Scopus, Cochrane Central Register of Controlled Trials, Agency for Healthcare Research and Quality, ProQuest Dissertations and Theses, MedNar and US National Institutes of Health clinical trials. A three-step search strategy was utilized in this review. Initial keywords used were automated external defibrillator, cardiac arrest, hospital and adult. Methodological quality The studies included in the review were of moderate quality for quasi-experimental pre-post design. All included studies met the criteria of reporting the number of withdrawals. Studies used a standardized format of Utstein-style to report outcome measures and appropriate statistical tests for data analysis were applied. Data collection Data was extracted using standardized templates provided in the Joanna Briggs Institute Meta Analysis of Statistics Assessment and Review Instrument software. Data synthesis Meta-analysis was performed using random effect model. The effect size was expressed as an odds ratio. Results Three studies with a total of 1296 participants were included in this review. Only 16% of the initial cardiac rhythms were shockable. There was no difference on a return of spontaneous circulation or patient survival to hospital discharge among the patients who received automated external defibrillation compared to those who received manual/standard external defibrillation Conclusions Using automated external defibrillation by trained healthcare professionals in the hospital setting does not contribute to improving patient survival after suffering cardiac arrest.

Anesthesia Literature Review

Anesthesia Literature Review

Effectiveness of automated external defibrillation on survival outcomes among adult patients after in-hospital cardiac arrest: a systematic review

Background Cardiac arrest is defined as cessation of cardiac mechanical activity. “Chain of survival” was introduced in 1991 to improve survival after sudden cardiac arrest. Earlier defibrillation by an automated external defibrillator (AED) saves lives and improves the odds of survival for patients who suffer a sudden cardiac arrest outside the hospital. However, its role in a hospital setting has received conflicting results. Objectives The objective of this review was to identify the effectiveness of automated external defibrillation achieving the return of spontaneous circulation and survival to hospital discharge in adult patients after an in-hospital cardiac arrest. Inclusion criteria Types of participants The participants were 18 years old and above and suffering from sudden cardiac arrest in the hospital setting. Type of intervention The intervention of interest was use of an automated external cardiac defibrillator operated by trained healthcare professionals. Types of studies This review included any experimental study design including randomized controlled trials, non-randomized controlled trials, and quasi-experimental designs, including before and after studies. Types of outcomes The outcome measures were initial cardiac arrest rhythms, number of patients with a spontaneous return of circulation for at least 20 minutes during resuscitation, and number of patients surviving to hospital discharge. Search strategy The search strategy aimed to find both published and unpublished studies in ten databases from 2001 to 2012. Namely Medline, CINAHL, Embase, Web of Knowledge, Scopus, Cochrane Central Register of Controlled Trials, Agency for Healthcare Research and Quality, ProQuest Dissertations and Theses, MedNar and US National Institutes of Health clinical trials. A three-step search strategy was utilized in this review. Initial keywords used were automated external defibrillator, cardiac arrest, hospital and adult. Methodological quality The studies included in the review were of moderate quality for quasi-experimental pre-post design. All included studies met the criteria of reporting the number of withdrawals. Studies used a standardized format of Utstein-style to report outcome measures and appropriate statistical tests for data analysis were applied. Data collection Data was extracted using standardized templates provided in the Joanna Briggs Institute Meta Analysis of Statistics Assessment and Review Instrument software. Data synthesis Meta-analysis was performed using random effect model. The effect size was expressed as an odds ratio. Results Three studies with a total of 1296 participants were included in this review. Only 16% of the initial cardiac rhythms were shockable. There was no difference on a return of spontaneous circulation or patient survival to hospital discharge among the patients who received automated external defibrillation compared to those who received manual/standard external defibrillation Conclusions Using automated external defibrillation by trained healthcare professionals in the hospital setting does not contribute to improving patient survival after suffering cardiac arrest. Implications for practice Training of health care professionals is not recommended for a hospital, which already has a strong resuscitation team as there were no additional benefits of automated external defibrillation on improving patient's survival. Implications for research More research is needed to redesign an AED that does not require the operators to stop cardiac pulmonary resuscitation for defibrillations. The effectiveness of AED should be examined in hospitals in rural areas or hospitals with limited access to resuscitation teams.

Survival Trends in Pediatric In-Hospital Cardiac Arrests

Despite ongoing efforts to improve the quality of pediatric resuscitation, it remains unknown whether survival in children with in-hospital cardiac arrest has improved. Between 2000 and 2009, we identified children (<18 years of age) with an in-hospital cardiac arrest at hospitals with >3 years of participation and >5 cases annually within the national Get With The Guidelines-Resuscitation registry. Multivariable logistic regression was used to examine temporal trends in survival to discharge. We also explored whether trends in survival were attributable to improvement in acute resuscitation or postresuscitation care and examined trends in neurological disability among survivors. Among 1031 children at 12 hospitals, the initial cardiac arrest rhythm was asystole and pulseless electrical activity in 874 children (84.8%) and ventricular fibrillation and pulseless ventricular tachycardia in 157 children (15.2%), with an increase in cardiac arrests due to pulseless electrical activity over time (P for trend <0.001). Risk-adjusted rates of survival to discharge increased from 14.3% in 2000 to 43.4% in 2009 (adjusted rate ratio per year, 1.08; 95% confidence interval, 1.01-1.16; P for trend=0.02). Improvement in survival was driven largely by an improvement in acute resuscitation survival (risk-adjusted rates: 42.9% in 2000, 81.2% in 2009; adjusted rate ratio per year: 1.04; 95% confidence interval, 1.01-1.08; P for trend=0.006). Moreover, survival trends were not accompanied by higher rates of neurological disability among survivors over time (unadjusted P for trend=0.32), suggesting an overall increase in the number of survivors without neurological disability over time. Rates of survival to hospital discharge in children with in-hospital cardiac arrests have improved over the past decade without higher rates of neurological disability among survivors.

579

Introduction: Regionalization of care for high-acuity critical illness is an emerging paradigm that is now advocated for post-cardiac arrest care. Hypothesis: To establish feasability and outcomes of a regional approach to post-cardiac arrest care based at a referral cardiac resuscitation center. Methods: We implemented processes to facilitate early care and transfer of comatose cardiac arrest victims from regional hospitals to a referral cardiac resuscitation center. This is a prospective observational study of all local and referred patients treated in a post-cardiac arrest clinical pathway that included therapeutic hypothermia from November 2007 through June 2011. Clinical data including arrest factors, treatment variables and outcome were collected on consecutive patients with the use of a preformatted standard data collection tool utilizing Utstein criteria. Pittsburgh cerebral performance category (CPC) 1-2 was considered a good neurologic outcome. Results: A total of 220 patients were enrolled; 127 (58%) patients were local direct admissions from our community and 93 (42%) were transferred from one of 24 outlying hospitals. Median age was 57 ± 15 years, median time of arrest to ROSC was 19 minutes (IQR 10-29 minutes), median GCS at enrollment was 3 (IQR 3-3) and 62% of patients presented with a shockable initial cardiac arrest rhythm. STEMI at presentation was the only statistically significant difference in demographic or arrest factors between local and referred patients (8% vs 19%; p=0.01). The primary outcome of good neurologic function was observed in 43% (95% CI: 32% to 48%) of the entire study group and 86% (95% CI: 81% to 94%) of survivors. There was no difference in survival with good neurologic outcome among local and referred patients (46% vs 39%, P=0.3). Conclusions: A regionalized approach to post-cardiac arrest care centering on a referral cardiac resuscitation center is feasible and effective. Medical centers providing state-of-the-art post-cardiac arrest care may impact a greater patient population by working toward local regionalization using previously established referral relationships for other high acuity diseases such STEMI, trauma and acute stroke.

Abstract 71: A Novel Animal Model of Pulseless Electrical Activity Cardiac Arrest: Adrenergic Blockade and Coronary Occlusion

Introduction: The incidence of VF as the first documented rhythm in out-of-hospital cardiac arrest (OOHCA) has been declining, while the incidence of pulseless electrical activity (PEA) has been increasing. The increasing proportion of PEA as the initial rhythm for OOHCA has paralleled the increasing use of adrenergic antagonist therapy in the population most at risk for cardiac arrest. We hypothesized that PEA cardiac arrest can result from acute coronary occlusion in the setting of pre-arrest adrenergic blockade. Methods: Twenty-six anesthetized and instrumented immature male swine (mean weight 36 kg) were pre-treated with an infusion of labetalol, a β-1 and α-1 adrenergic blocker (mean dose 6 ± 3 mg/kg). Adequacy of adrenergic blockade was determined using an intravenous challenge of epinephrine 0.1 mg IV. After challenge and return to baseline, balloon occlusion of the left anterior descending (LAD) or proximal right coronary artery (RCA) was performed and the rhythm and hemodynamic response observed during sustained occlusion. Results: Occlusion of the RCA was followed by PEA or pseudo-PEA (defined as an organized rhythm with systolic arterial pressure &lt;50 mm Hg) in 10/13 animals (77%). During RCA occlusion, cooling of the vagus nerve (reversible thermal vagotomy) did not prevent the hypotensive hemodynamic response. LAD occlusion was followed by PEA in 6/13 animals (46%). Brief occlusion of the RCA followed by occlusion of the LAD was followed by PEA in 5/7 animals (71%). Conclusions: Adrenergic blockade followed by coronary occlusion may be followed by PEA. This combination may play a role in the declining incidence of VF as the initial cardiac arrest rhythm in out-of-hospital cardiac arrest.

Trends in Survival after In-Hospital Cardiac Arrest

BackgroundDespite advances in resuscitation care in recent years, it is not clear whether survival and neurologic function after in-hospital cardiac arrest have improved over time.MethodsWe identified all adults who had an in-hospital cardiac arrest at 374 hospitals in the Get with the Guidelines–Resuscitation registry between 2000 and 2009. Using multivariable regression, we examined temporal trends in risk-adjusted rates of survival to discharge. Additional analyses explored whether trends were due to improved survival during acute resuscitation or postresuscitation care and whether they occurred at the expense of greater neurologic disability in survivors.ResultsAmong 84,625 hospitalized patients with cardiac arrest, 79.3% had an initial rhythm of asystole or pulseless electrical activity, and 20.7% had ventricular fibrillation or pulseless ventricular tachycardia. The proportion of cardiac arrests due to asystole or pulseless electrical activity increased over time (P<0.001 for trend). Risk-adjusted rates of survival to discharge increased from 13.7% in 2000 to 22.3% in 2009 (adjusted rate ratio per year, 1.04; 95% confidence interval [CI], 1.03 to 1.06; P<0.001 for trend). Survival improvement was similar in the two rhythm groups and was due to improvement in both acute resuscitation survival and postresuscitation survival. Rates of clinically significant neurologic disability among survivors decreased over time, with a risk-adjusted rate of 32.9% in 2000 and 28.1% in 2009 (adjusted rate ratio per year, 0.98; 95% CI, 0.97 to 1.00; P=0.02 for trend).ConclusionsBoth survival and neurologic outcomes after in-hospital cardiac arrest have improved during the past decade at hospitals participating in a large national quality-improvement registry. (Funded by the American Heart Association.)

A Validated Prediction Tool for Initial Survivors of In-Hospital Cardiac Arrest

Accurate estimation of favorable neurological survival after in-hospital cardiac arrest could provide critical information for physicians, patients, and families. Within the Get With the Guidelines-Resuscitation registry, we identified 42,957 patients from 551 hospitals admitted between January 2000 and October 2009 who were successfully resuscitated from an in-hospital cardiac arrest. A simple prediction tool for favorable neurological survival in patients successfully resuscitated from an in-hospital cardiac arrest was developed using multivariate logistic regression, with two-thirds of the sample randomly selected as the derivation cohort and one-third as the validation cohort. Favorable neurological status was defined as the absence of severe neurological deficits (cerebral performance category score of ≤2). Rates of favorable neurological survival were similar in the derivation cohort (7052 patients [24.6%]) and validation cohort (3510 patients [24.5%]). Eleven variables were associated with favorable neurological survival: younger age, initial cardiac arrest rhythm of ventricular fibrillation or pulseless ventricular tachycardia with a defibrillation time of 2 minutes or less, baseline neurological status without disability, arrest location in a monitored unit, shorter duration of resuscitation, and absence of mechanical ventilation, renal insufficiency, hepatic insufficiency, sepsis, malignant disease, and hypotension prior to the arrest. The model had excellent discrimination (C statistic of 0.80 for both the derivation and validation cohorts) and calibration. The prediction tool demonstrated the ability to identify patients across a wide range of rates of favorable neurological survival: patients in the top decile had a 70.7% probability of this outcome, whereas patients in the bottom decile had a 2.8% probability. Among successfully resuscitated patients with an in-hospital cardiac arrest, a simple, bedside prediction tool provides robust estimates of the probability of favorable neurological survival. This tool permits accurate prognostication after cardiac arrest for physicians, patients, and families.

Primary Cardiac Arrest Following Sport or Exertion in Children Presenting to an Emergency Department

The objective of this study was to describe the characteristics and outcome of pediatric patients presenting to an emergency department (ED) following out-of-hospital primary cardiac arrest (OHPCA), to determine if long-term survival is influenced by specific resuscitation interventions. This was a prospective observational study of cases of OHPCA during sport or exertion in young patients presenting to an ED over a 5-year period. Cases were identified from a resuscitation database, which documented patient demographics, nature of event, emergency treatment, response times, and clinical progress. These data were analyzed to determine outcomes. Nine children were identified who presented following OHPCA during the study period. The mean age was 10.7 (±4.2) years. All were subsequently diagnosed with an underlying primary cardiac disorder. Six patients (66.6%) survived to make a full recovery. All patients who survived had received early chest compressions (within 5 minutes) and early defibrillation (within 10 minutes). The initial cardiac arrest rhythm in all survivors had been an electrically cardiovertable rhythm. Five (83%) of the 6 survivors did not receive epinephrine during resuscitation. The importance of early chest compressions and defibrillation in collapsed young athletes is highlighted in this report. These interventions can result in full long-term neurological recovery. Use of epinephrine in these patients may be dangerous. We suggest that special consideration should be given to this subgroup of patients in the development of future resuscitation guidelines.