Numerators, denominators, and survival rates: reporting survival from out-of-hospital cardiac arrest

International Initiation and Termination of Resuscitation Practices

BACKGROUND

Substantial variation in survival following out-of-hospital cardiac arrest is described both internationally and nationally. The Utstein factors account for half of the variation, but the remaining is not fully understood. Local regulations or guidelines concerning the withholding and termination of resuscitation may influence the reporting of cardiac arrests when comparing outcomes between different EMS systems.

METHOD

We have developed an online cross-sectional mixed-methods explanatory design survey aimed at describing the international and national variations in the initiation, the termination of resuscitation, and the refraining from resuscitation of adult patients (>18 years of age) suffering from non-traumatic OHCA. The respondents will be national experts and the questionnaire will be distributed among members of EUPHOREA, the International Liaison Committee of Resuscitation (ILCOR), the European Resuscitation Council, and the Resuscitation Academy. Each invited country will have to identify at least two national experts with special expertise in prehospital resuscitation practices. We exclude countries with less than two respondents.

RESULTS

The survey will provide both quantitative and qualitative data. Quantitative data will be presented as frequencies and proportions. Qualitative data will be analyzed using content analysis.

CONCLUSION

This survey could be of importance in understanding the multiple factors leading to the substantial variation in survival found following OHCA. Furthermore, the interpretation of future studies on OHCA from different settings may be improved to further increase survival following OHCA.

Survival to hospital discharge is equivalent to 30-day survival as a primary survival outcome for out-of-hospital cardiac arrest studies

AIM

The 2015 Utstein guidelines stated that 30-day survival could be used as an alternative to survival to hospital discharge (STHD) as the primary survival outcome in out-of-hospital cardiac arrest (OHCA) studies. We sought to ascertain the equivalence (concordance) of these two survival outcome measures.

METHODS

We conducted a population-based retrospective cohort study of OHCA patients who were attended by St John Western Australia (SJ-WA) paramedics in Perth, WA between 1999 and 2018. OHCA patients were included if they received either an attempted resuscitation by SJ-WA or bystander defibrillation; were a resident of WA; and were transported to a hospital emergency department (ED). STHD was determined through hospital record review and 30-day survival via the WA Death Registry and cemetery registration data.

RESULTS

The study cohort comprised a total of 7953 OHCA patients, predominantly male (70%), with a median (IQR) age of 63 (46-77 years), a presumed cardiac arrest aetiology (78.9%), and the majority occurred in a private residence (66.8%). Survival rates were identical for STHD and 30-day survival, with both being (13.78%, 95% CI: 13.02-14.54%) (p = 0.99). The overall concordance between the two survival rates was 99.6%. There were only 30 (0.4%) discordant cases in total: 15 cases with STHD-yes but 30-day survival-no; and 15 cases with STHD-no but 30-day survival-yes.

CONCLUSION

We found that STHD and 30-day survival were equivalent survival metrics in our OHCA Registry. However, given potential differences in health systems, we suggest that 30-day survival is likely to enable more reliable comparisons across jurisdictions.

Incidence and Outcomes of Out-of-Hospital Cardiac Arrest in Singapore and Victoria: A Collaborative Study

Background

Incidence and outcomes of out‐of‐hospital cardiac arrest (OHCA) vary between communities. We aimed to examine differences in patient characteristics, prehospital care, and outcomes in Singapore and Victoria.

Methods and Results

Using the prospective Singapore Pan‐Asian Resuscitation Outcomes Study and Victorian Ambulance Cardiac Arrest Registry, we identified 11 061 and 32 003 emergency medical services‐attended adult OHCAs between 2011 and 2016 respectively. Incidence and survival rates were directly age adjusted using the World Health Organization population. Survival was analyzed with logistic regression, with model selection via backward elimination. Of the 11 061 and 14 834 emergency medical services‐treated OHCAs (overall mean age±SD 65.5±17.2; 67.4% males) in Singapore and Victoria respectively, 11 054 (99.9%) and 5595 (37.7%) were transported, and 440 (4.0%) and 2009 (13.6%) survived. Compared with Victoria, people with OHCA in Singapore were older (66.7±16.5 versus 64.6±17.7), had less shockable rhythms (17.7% versus 30.3%), and received less bystander cardiopulmonary resuscitation (45.7% versus 58.5%) and defibrillation (1.3% versus 2.5%) (all P<0.001). Age‐adjusted OHCA incidence and survival rates increased in Singapore between 2011 and 2016 (P<0.01 for trend), but remained stable, though higher, in Victoria. Likelihood of survival increased significantly (P<0.001) with arrest in public locations (adjusted odds ratio [aOR] 1.81), witnessed arrest (aOR 2.14), bystander cardiopulmonary resuscitation (aOR 1.72), initial shockable rhythm (aOR 9.82), and bystander defibrillation (aOR 2.04) but decreased with increasing age (aOR 0.98) and emergency medical services response time (aOR 0.91).

Conclusions

Singapore reported increasing OHCA incidence and survival rates between 2011 and 2016, compared with stable, albeit higher, rates in Victoria. Survival differences might be related to different emergency medical services practices including patient selection for resuscitation and transport.

The global survival rate among adult out-of-hospital cardiac arrest patients who received cardiopulmonary resuscitation: a systematic review and meta-analysis

Background

To quantitatively summarize the available epidemiological evidence on the survival rate of out-of-hospital cardiac arrest (OHCA) patients who received cardiopulmonary resuscitation (CPR).

Methods

We systematically searched the PubMed, Embase, and Web of Science databases, and the references of retrieved articles were manually reviewed to identify studies reporting the outcome of OHCA patients who received CPR. The overall incidence and outcome of OHCA were assessed using a random-effects meta-analysis.

Results

A total of 141 eligible studies were included in this meta-analysis. The pooled incidence of return of spontaneous circulation (ROSC) was 29.7% (95% CI 27.6–31.7%), the rate of survival to hospital admission was 22.0% (95% CI 20.7–23.4%), the rate of survival to hospital discharge was 8.8% (95% CI 8.2–9.4%), the pooled 1-month survival rate was 10.7% (95% CI 9.1–13.3%), and the 1-year survival rate was 7.7% (95% CI 5.8–9.5%). Subgroup analysis showed that survival to hospital discharge was more likely among OHCA patients whose cardiac arrest was witnessed by a bystander or emergency medical services (EMS) (10.5%; 95% CI 9.2–11.7%), who received bystander CPR (11.3%, 95% CI 9.3–13.2%), and who were living in Europe and North America (Europe 11.7%; 95% CI 10.5–13.0%; North America: 7.7%; 95% CI 6.9–8.6%). The survival to discharge (8.6% in 1976–1999 vs. 9.9% in 2010–2019), 1-month survival (8.0% in 2000–2009 vs. 13.3% in 2010–2019), and 1-year survival (8.0% in 2000–2009 vs. 13.3% in 2010–2019) rates of OHCA patients who underwent CPR significantly increased throughout the study period. The Egger’s test did not indicate evidence of publication bias for the outcomes of OHCA patients who underwent CPR.

Conclusions

The global survival rate of OHCA patients who received CPR has increased in the past 40 years. A higher survival rate post-OHCA is more likely among patients who receive bystander CPR and who live in Western countries.

Electronic supplementary material

The online version of this article (10.1186/s13054-020-2773-2) contains supplementary material, which is available to authorized users.

Ethical challenges of adult ECMO

The use of extracorporeal membrane oxygenation (ECMO) is expanding rapidly, and as more centres streamline their management policies, the bioethics literature on ECMO has been highlighting the ethical challenges of using an expensive, resource-intensive technology including its eligibility, duration of support, cost-effectiveness and societal repercussions. The absence of high-quality studies on long-term outcomes of ECMO survivors leads to multiple ethical problems involving patient autonomy, beneficence and clinical wisdom pertaining to its initiation, maintenance and termination. This article reviews some of the ethical challenges that affect decision-making during ECMO therapy and suggests an ethical framework that may help the treating team deal with such conundrums, when the patient does not recover despite being on ECMO.

Effect of smart devices on the quality of CPR training: A systematic review

AIM OF THE REVIEW

Use of smart devices to provide real-time cardiopulmonary resuscitation (CPR) feedback in the context of out-of-hospital cardiac arrest (OHCA) has considerable potential for improving survival. However, the findings of previous studies evaluating the effectiveness of these devices have been conflicting. Therefore, we conducted a systematic review of the literature to assess the utility of smart devices for improving the quality of CPR during CPR training.

DATA SOURCES

Thirteen electronic databases were searched. The articles were reviewed according to the eligibility criteria. CPR quality was evaluated based on the rates and depths of chest compression, and the proportion of adequate depth of chest compressions.

RESULTS

Ultimately, 11 studies (5 randomised controlled trials, 1 randomised trial, and 5 randomised cross-over trials) were selected for this systematic review. Eight of these studies used smartphones and three used smartwatches. This review did not find an apparent benefit from smart device use during CPR in terms of maintaining the recommended compression rates and depths of chest compressions. However, all three smartwatch studies reported that the proportion of chest compressions of adequate depth was significantly improved with smartwatch use (smartwatch group vs. non-smartwatch group in the three studies: 65.01% vs. 45.15%, p = 0.01; 64.6% vs. 43.1%, p = 0.049; 98.7% vs. 79.3%, p = 0.002).

CONCLUSION

This review does not find durable evidence for usefulness of smart devices in CPR training. However, the smartwatches may improve the accuracy of chest compression depth. Future studies with larger sample sizes might be necessary before reaching a firm conclusion.

Outcomes After Pediatric Out-of-Hospital Cardiopulmonary Interventions

OBJECTIVE

The aim of the study was to evaluate outcomes after pediatric out-of-hospital cardiopulmonary interventions (CPIs) by emergency medical services (EMS).

METHODS

Children (age, ≤18 years) who received CPI by EMS from 2001 to 2008 were identified from the Utah Department of Health. Cardiopulmonary intervention was defined as oxygenation, ventilation or CPR, and transport to a hospital by EMS. Univariate and multivariable regression analyses evaluated associations between potential predictors and outcomes (death and new neurologic dysfunction).

RESULTS

A total of 464 patients (58% male) received EMS attention. For the 71% patients (327) who were alive on EMS arrival, 63% (205) received CPI without CPR. Of note, 6% (12) of these patients died after arrival to the hospital and new neurologic dysfunction was diagnosed in 6% (13). Among the 12 patients who died, 50% (6) were younger than 1 year.On multivariable regression analysis, factors associated with increased risk of death before and in-hospital are the following: age younger than 1 year (odds ratio [OR], 0.26; 95% confidence interval [CI], 0.17-0.39), shorter EMS transport time (OR, 0.94; 95% CI, 0.89-0.99), and longer EMS dispatch time (OR, 1.23; 95% CI, 1.08-1.40). Factors associated with increased risk of new neurologic dysfunction are the following: lack of pulse (OR, 0.14; 95% CI, 0.04-0.53), requiring CPR (OR, 6.15; 95% CI, 1.48-25.6), and CPR duration (OR, 1.20; 95% CI, 1.05-1.37).

CONCLUSIONS

Age younger than 1 year, shorter transport time, and longer dispatch time were associated with increased risk of death. Being pulseless upon discovery and receiving CPR were associated with new neurologic dysfunction. Maximizing EMS transport interventions for patients younger than 1 year requiring CPI may improve patient outcomes.

Out-of-Hospital Cardiac Arrest in a Teaching Hospital in Hong Kong: Descriptive Study Using the Utstein Style

Objective

To describe, using the Utstein template, the characteristics of patients presenting with out-of-hospital cardiac arrest to a university teaching hospital in the New Territories of Hong Kong, and to evaluate survival.

Design

Prospective study.

Setting

The emergency department of a teaching hospital in the New Territories, Hong Kong.

Participants

Patients older than 12 years with non-traumatic out-of-hospital cardiac arrest who were transported to the hospital between 1 July 2002 and 31 December 2002.

Main outcome measures

Demographic data, characteristics of cardiac arrest and response time intervals of the emergency medical service presented according to the Utstein style, and also survival to hospital discharge rate.

Results

A total of 124 patients were included (49.2% male; mean age 71.9 years). The majority of cardiac arrests occurred in patients' home. The overall bystander cardiopulmonary resuscitation (CPR) rate was 15.3% (19/124). The most common electrocardiographic rhythm at scene was asystole, whilst pulseless ventricular tachycardia (VT)/ventricular fibrillation (VF) was found in 18.0%. The overall survival was 0.8% (1/124), and survival to hospital discharge was significantly higher for patients with VF or pulseless VT than those patients with other rhythms of cardiac arrest (11.1% versus 0%). The median witnessed/recognised collapse to defibrillation time was 14 minutes. The median prehospital time interval from collapse/recognition to arrival at hospital was 33 minutes.

Conclusion

The prognosis of out-of-hospital cardiac arrest in Hong Kong was poor. Major improvements in every component of the chain of survival are necessary.

When is a Cardiac Arrest Non-Cardiac?

Introduction While the overall survival rate for out-of-hospital cardiac arrest (OHCA) is low, ranging from 5%-10%, several characteristics have been shown to decrease mortality, such as presence of bystander cardiopulmonary resuscitation (CPR), witnessed vs unwitnessed events, and favorable initial rhythm (VF/VT). More recently, studies have shown that modified CPR algorithms, such as chest-compression only or cardio-cerebral resuscitation, can further increase survival rates in OHCA. Most of these studies have included only OHCA patients with "presumed cardiac etiology," on the assumption that airway management is of lesser impact than chest compressions in these patients. However, prehospital personnel often lack objective and consistent criteria to assess whether an OHCA is of cardiac or non-cardiac etiology. Hypothesis/Problem The relative proportions of cardiac vs non-cardiac etiology in published data sets of OHCA in the peer-reviewed literature were examined in order to assess the variability of prehospital clinical etiology assessment.

METHODS

A Medline (US National Library of Medicine, National Institutes of Health; Bethesda, Maryland USA) search was performed using the subject headings "OHCA" and "Emergency Medical Services" (EMS). Studies were included if they reported prevalence of cardiac etiology among OHCA in the entire patient sample, or in all arms of a comparison study. Studies that either did not report etiology of OHCA, or that excluded all cardiac or non-cardiac etiologies prior to reporting clinical data, were excluded.

RESULTS

Twenty-four studies were identified, containing 27 datasets of OHCA which reported the prevalence of presumed cardiac vs non-cardiac etiology. These 27 datasets were drawn from 15 different countries. The prevalence of cardiac etiology among OHCA ranged from 50% to 91%. No obvious patterns were found regarding database size, year of publication, or global region (continent) of origin.

CONCLUSIONS

There exists significant variation in published rates of cardiac etiology among OHCAs. While some of this variation likely reflects different actual rates of cardiac etiologies in the sampled populations, varying definitions of cardiac etiology among prehospital personnel or varying implementation of existing definitions may also play a role. Different proportions of cardiac vs non-cardiac etiology of OHCA in a sample could result in entirely different interpretations of data. A more specific consensus definition of cardiac etiology than that which currently exists in the Utstein template may provide better guidance to prehospital personnel and EMS researchers in the future. Carter RM , Cone DC . When is a cardiac arrest non-cardiac? Prehosp Disaster Med. 2017;32(5):523-527.

Outcome of out-of-hospital cardiac arrests in Beijing, China

AIM

The purpose of this study was to assess the outcome of out-of-hospital cardiac arrests (OHCAs) in Beijing, China.

METHODS

In this prospective study, data were collected according to the Utstein style on all cases of OHCA that occurred between January and December 2012 in urban areas covered by Beijing Emergency Medical Services (EMS). The cases were followed-up for 1 year.

RESULTS

Out of the 9897 OHCAs recorded, cardiopulmonary resuscitation (CPR) was initiated in 2421 patients (24.4%). Among the CPR-receivers (n=2421), 1804 patients (74.5%) had collapsed at home, while 375 patients (15.5%) at a public place. The average time interval from call to EMS arrival at the collapse location was 16 min (range, 4-43 min). Of the 1693 OHCA cases with cardiac aetiology, 1246 cases (73.6%) were witnessed, and basic CPR was performed by bystanders before arrival of the EMS personnel in 193 patients (11.4%). Of the OHCAs with cardiac aetiology, 1054 patients (62.3%) had asystole, 131 patients (7.7%) had shockable rhythms, restoration of spontaneous circulation was achieved in 85 patients (5.0%), 71 patients (4.2%) were admitted to the hospital alive, and of the 22 patients (1.3%) who were discharged alive, 17 patients (1%) had good neurological outcomes. At 1 year post-OHCA, 17 patients were alive.

CONCLUSION

In the urban areas of Beijing with EMS services, survival rate after OHCA was unsatisfactory. Improvements are required in every link of the 'chain of survival'.

Prognostic values of blood ammonia and partial pressure of ammonia on hospital arrival in out-of-hospital cardiac arrests

PURPOSES

Outcome prediction for out-of-hospital cardiac arrest (OHCA) is of medical, ethical, and socioeconomic importance. We hypothesized that blood ammonia may reflect tissue hypoxia in OHCA patients and conducted this study to evaluate the prognostic value of ammonia for the return of spontaneous circulation (ROSC).

METHODS

This prospective, observational study was conducted in a tertiary university hospital between January 2008 and December 2008. The subjects consisted of OHCA patients who were sent to the emergency department (ED). The primary outcome was ROSC. The prognostic values were calculated for ammonia levels and the partial pressure of ammonia (pNH(3)), and the results were depicted as a receiver operating characteristics curve with an area under the curve.

RESULTS

Among 119 patients enrolled in this study, 28 patients (23.5%) achieved ROSC. Ammonia levels and pNH(3) in the non-ROSC group were significantly higher than those in the ROSC group (167.0 μmol/L vs 80.0 μmol/L, P < .05; 2.61 × 10(-5) vs 1.67 × 10(-5) mm Hg, P < .05, respectively). The predictive capacity of area under the curve for ammonia and pNH(3) for non-ROSC was 0.85 (95% confidence interval, 0.75-0.95) and 0.73 (95% confidence interval, 0.61-0.84), respectively. The multivariate analysis confirmed that ammonia and pNH(3) are independent predictors of non-ROSC. The prognostic value of ammonia was better than that of pNH(3). The cutoff level for ammonia of 84 μmol/L was 94.5% sensitive and 75.0% specific for predicting non-ROSC with a diagnostic accuracy of 89.9%.

CONCLUSIONS

Hyperammonemia on ED arrival is independently predictive of non-ROSC for OHCA patients. The findings may offer useful information for clinical management.

Collapse-to-emergency medical service cardiopulmonary resuscitation interval and outcomes of out-of-hospital cardiopulmonary arrest: a nationwide observational study

Introduction

The relationship between collapse to emergency medical service (EMS) cardiopulmonary resuscitation (CPR) interval and outcome has been well documented. However, most studies have only analyzed cases of cardiac origin and Vf (ventricular fibrillation)/pulseless VT (ventricular tachycardia). We sought to examine all causes of cardiac arrest and analyze the relationship between collapse-to-EMS CPR interval and outcome in a nationwide sample using an out-of-hospital cardiac arrest (OHCA) registry.

Methods

This was a retrospective observational study based on a nationwide OHCA patient registry in Japan between 2005 and 2008 (n = 431,968). We included cases where collapse was witnessed by a bystander and where collapse and intervention time were recorded (n = 109,350). Data were collected based on the Utstein template. One-month survival and neurologically favorable one-month survival were used as outcome measures. Logarithmic regression and logistic regression were used to examine the relation between outcomes and collapse-to-EMS CPR interval.

Results

Among collapse-to-EMS CPR intervals between 3 and 30 minutes, the logarithmic regression equation for the relationship with one-month survival was y = -0.059 ln(x) + 0.21, while that for the relationship with neurologically favorable one-month survival was y = -0.041 ln(x) + 0.13. After adjusting for potential confounders in the logistic regression analysis for all intervals, longer collapse-to-EMS CPR intervals were associated with lower rates of one-month survival (odds ratio (OR) 0.93, 95% confidence interval (CI): 0.93 to 0.93) and neurologically favorable one-month survival (OR 0.89, 95% CI 0.89 to 0.90).

Conclusions

Improving the emergency medical system and CPR in cases of OHCA is important for improving the outcomes of OHCA.

Variation in out-of-hospital cardiac arrest resuscitation and transport practices in the Resuscitation Outcomes Consortium: ROC Epistry-Cardiac Arrest

OBJECTIVES

To identify variation in patient, event, and scene characteristics of out-of-hospital cardiac arrest (OOHCA) patients assessed by emergency medical services (EMS), and to investigate variation in transport practices in relation to documented prehospital return of spontaneous circulation (ROSC) within eight regional clinical centers participating in the Resuscitation Outcomes Consortium (ROC) Epistry-Cardiac Arrest.

METHODS

OOHCA patient, event, and scene characteristics were compared to identify variation in treatment and transport practices across sites. Findings were adjusted for site and standard Utstein covariates. Using logistic regression, these covariates were modeled to identify factors related to the initiation of transport without documented prehospital ROSC as well as survival in these patients.

SETTING

Eight US and Canadian sites participating in the ROC Epistry-Cardiac Arrest.

POPULATION

Persons ≥ 20 years with OOHCA who (a) received compressions or shock by EMS providers and/or received bystander AED shock or (b) were pulseless but received no EMS compressions or shock between December 2005 and May 2007.

RESULTS

23,233 OOHCA cases were assessed by EMS in the defined period. Resuscitation (treatment) was initiated by EMS in 13,518 cases (58%, site range: 36-69%, p < 0.0001). Of treated cases, 59% were transported (site range: 49-88%, p < 0.0001). Transport was initiated in the absence of documented ROSC for 58% of transported cases (site range: 14-95%, p < 0.0001). Of these transported cases, 8% achieved ROSC before hospital arrival (site range: 5-21%, p < 0.0001) and 4% survived to hospital discharge (site range: 1-21%, p < 0.0001). In cases with transport from the scene initiated after documented ROSC, 28% survived to hospital discharge (site range: 18-44%, p < 0.0001).

CONCLUSION

Initiation of resuscitation and transport of OOHCA and the reporting of ROSC prior to transport markedly varies among ROC sites. This variation may help clarify reported differences in survival rates among sites and provide a target for identifying EMS practices most likely to enhance survival from OOHCA.

Hypoxisch-ischämische Enzephalopathie (HIE) nach Herz-Kreislaufstillstand (HKS) – Pathophysiologie, Prognose und Outcome eines „vernachlässigten“ Krankheitsbildes

Durch die Fortschritte in der Reanimations- und Intensivmedizin steigt die Anzahl von Patienten mit einer Hypoxisch-ischämischen Enzephalopathie (HIE). Das klinische Ausprägungsspektrum dieses Krankheitsbildes reicht von milden kognitiven Dysfunktionen bis hin zum Versterben des Patienten. Der Übersichtsartikel beleuchtet mögliche Entwicklungsverläufe dieser Patientenpopulation vom Akutstadium der Erkrankung bis in die postrehabilitative Phase unter besonderer Gewichtung der zu Grunde liegenden pathophysiologischen Mechanismen, der Prognosestellung sowie des neuropsychologischen und psychosozialen Outcomes. Dabei wird verdeutlicht, dass Verbesserungen in der akuten Rettungs- und Intensivmedizin gleichsam mit Verbesserungen des rehabilitativen und vor allem des postrehabilitativen Versorgungssystems einhergehen müssen – sowohl für Patienten als auch deren Angehörigen.

Prearrest signs of shock and respiratory insufficiency in out-of-hospital cardiac arrests witnessed by crew of the emergency medical service

AIM

The objective of this study is to determine whether prearrest shock and respiratory insufficiency influence outcome in patients with emergency medical service-witnessed out-of-hospital cardiac arrest.

METHODS

Analysis of data from a cardiac arrest database and data from the ambulance charts was performed. For the purpose of the study, shock was defined as prearrest heart rate below 40 or above 140/min, systolic blood pressure as below 90 mm Hg, and respiratory insufficiency as respiratory rate above 36 or oxygen saturation below 90%. Adjusted odds ratios (ORs) with 95% confidence intervals (CIs) were calculated.

RESULTS

Of a total of 303 patients, 81% had prearrest shock or respiratory insufficiency. Mortality was higher in these patients indicated by fewer with return of spontaneous circulation (43% vs 75%, P < .001), and lower survival to hospital admission (31% vs 71%, P < .001) and to discharge (13% vs 59%, P < .001). Independent predictors of mortality were age (OR, 1.04; CI, 1.0-1.06), initial rhythm other than ventricular fibrillation or ventricular tachycardia (OR, 32.9; CI, 10.9-99.0), and respiratory insufficiency (OR, 4.2; CI, 1.4-12.5).

CONCLUSIONS

Shock and respiratory depression are common among patients with out-of-hospital cardiac arrest witnessed by the emergency medical service, and these patients have a high mortality when compared with patients without shock or respiratory failure.

Alcohol, drug misuse and suicide attempts: unrecognised causes of out of hospital cardiac arrests admitted to intensive care units

AIM

To assess the contribution of alcohol, drug abuse and suicide attempts to out of hospital cardiac arrests (OHCA) who are admitted to our intensive care unit (ICU).

METHODS

Retrospective review of all OHCA admitted to the ICU over a 2-year period.

RESULTS

There were 26 OHCA. Six patients survived, all of whom had a cardiac aetiology for their arrest. Ten patients arrested due to external factors (drug misuse n = 4, alcohol excess n = 1, suicide attempts n = 4 and accidental choking n = 1). All of the patients who arrested secondary to external factors were young (37.2 +/- 13.58 years), 90% were male and all died in hospital. All of the cases of drug misuse involved cocaine.

CONCLUSION

Alcohol, drug misuse and suicide attempts contribute significantly to the number of OHCA which are admitted to ICU. Moreover, cocaine usage has contributed to a number of OHCA in our study.

Delay prior to calling 9-1-1 is associated with increased mortality after out-of-hospital cardiac arrest

OBJECTIVE

We sought to characterize the collapse-to-9-1-1 call interval, to evaluate the frequency of pre-9-1-1 delay, and to assess whether delay is associated with decreased survival after out-of-hospital cardiac arrest (OHCA).

METHODS

This was a five-year prospective survey of bystanders to adult OHCA cases in which the victims were transported to seven local teaching hospitals in Michigan. Bystander data were obtained by telephone interview beginning two weeks after the event, and through review of emergency medical services (EMS) documents. Criteria for pre-9-1-1 delay were prospectively developed. Two paramedic reviewers were trained on these criteria and reviewed bystander and EMS data for each cardiac arrest case. Multivariate regression analysis was used to assess the independent impact of delay on survival. We collected common bystander and EMS OHCA demographics, as well as bystander description of events prior to the 9-1-1 call. Outcome was survival to hospital discharge.

RESULTS

During the study period we identified 1,004 OHCAs, for which 779 bystanders completed interviews. Of these interviews, 688 had adequate data for analysis. Raters showed moderate to strong agreement for a 15% subsample of cases. Of all cases, 330 (48%) were identified as having had pre-9-1-1 delay. Delay was less commonly associated with witnessed arrest (odds ratio [OR] 2.7; 95% confidence interval [CI] 2.0-3.7%) and public location (OR 1.57; 95% CI 1.1-2.2%). In a multivariate model, only initial-rhythm ventricular tachycardia/ventricular fibrillation was associated with improved survival (OR 2.28; 95% CI 1.3-4.1), and pre-9-1-1 delay was associated with decreased survival (OR 0.46; 95% CI 0.3-0.9%).

CONCLUSION

This method demonstrated that prehospital delay is common in OHCA and is associated with increased mortality. Measurement of pre-9-1-1 delay may improve precision of predictive models for OHCA survival.

A model of survival following pre-hospital cardiac arrest based on the Victorian Ambulance Cardiac Arrest Register

AIMS

This study describes the epidemiology of sudden cardiac arrest patients in Victoria, Australia, as captured via the Victorian Ambulance Cardiac Arrest Register (VACAR). We used the VACAR data to construct a new model of out-of-hospital cardiac arrest (OHCA), which was specified in accordance with observed trends.

PATIENTS

All cases of cardiac arrest in Victoria that were attended by Victorian ambulance services during the period of 2002-2005.

RESULTS

Overall survival to hospital discharge was 3.8% among 18,827 cases of OHCA. Survival was 15.7% among 1726 bystander witnessed, adult cardiac arrests of presumed cardiac aetiology, presenting in ventricular fibrillation or ventricular tachycardia (VF/VT), where resuscitation was attempted. In multivariate logistic regression analysis, bystander CPR, cardiac arrest (CA) location, response time, age and sex were predictors of VF/VT, which, in turn, was a strong predictor of survival. The same factors that affected VF/VT made an additional contribution to survival. However, for bystander CPR, CA location and response time this additional contribution was limited to VF/VT patients only. There was no detectable association between survival and age younger than 60 years or response time over 15min.

CONCLUSION

The new model accounts for relationships among predictors of survival. These relationships indicate that interventions such as reduced response times and bystander CPR act in multiple ways to improve survival.

Epidemiology and outcomes of out-of-hospital cardiac arrest in Rochester, New York

OBJECTIVE

To characterize out-of-hospital cardiac arrest (OHCA) and factors that affect survival in a medium sized city that uses system status management for dispatch.

METHODS

A retrospective cohort study of all adult OHCA patients treated by EMS between 1998 and 2001 was conducted using Utstein definitions. The primary endpoint was 1-year survival.

RESULTS

Of the 1177 patients who experienced OHCA during the study period, 539 (46%) met inclusion criteria. Age ranged from 18 to 98 years (median 67). The median call-response interval was 5 min (range 0-21), and 93% were 9 min or less. There was no significant difference in the median call-response intervals between call location zip (Post) codes (p=0.07). Twenty percent of experienced ROSC (95% CI 17-23), 7% survived more than 30 days (95% CI 5-9%), and 5% survived to 1 year (95% CI 3-7%). In bivariate analysis, first rhythm and bystander CPR affected survival to 1 year. There was no significant difference in survival between male (4%) and female (7%), black (4%) and white (6%), or witnessed (7%) and unwitnessed arrest (4%). Logistic regression identified younger age, CPR initiated by bystander (19%) or first responder (41%), and presenting rhythm of VF/VT (32%) as factors associated with survival to 1 year.

CONCLUSIONS

This study finds a 5% survival to 1 year among OHCA patients in Rochester, NY. A presenting rhythm of VF/VT and bystander CPR were associated with increased survival.

Measuring survival rates from sudden cardiac arrest: the elusive definition

BACKGROUND

Measuring survival from sudden out-of-hospital cardiac arrest (OOH-CA) is often used as a benchmark of the quality of a community's emergency medical service (EMS) system. The definition of OOH-CA survival rates depends both upon the numerator (surviving cases) and the denominator (all cases).

PURPOSE

The purpose of the public access defibrillation (PAD) trial was to measure the impact on survival of adding an automated external defibrillator (AED) to a volunteer response system trained in CPR. This paper reports the definition of OOH-CA developed by the PAD trial investigators, and it evaluates alternative statistical methods used to assess differences in reported "survival."

METHODS

Case surveillance was limited to the prospectively determined geographic boundaries of the participating trial units. The numerator in calculating a survival rate should include only those patients who survived an event but who otherwise would have died except for the application of some facet of emergency medical care-in this trial a defibrillatory shock. Among denominators considered were: total population of the study unit, all deaths within the study unit, and documented ventricular fibrillation cardiac arrests. The PAD classification focused upon cases that might have benefited from the early use of an AED, in addition to the likely benefit from early recognition of OOH-CA, early access of EMS, and early cardiopulmonary resuscitation (CPR). Results of this classification system were used to evaluate the impact of the PAD definition on the distribution of cardiac arrest case types between CPR only and CPR + AED units.

RESULTS

Potential OOH-CA episodes were classified into one of four groups: definite, probable, uncertain, or not an OOH-CA. About half of cardiac arrests in the PAD units were judged to be definite OOH-CA events and therefore potentially treatable with an AED. However, events that occurred in CPR-only units were less likely to be classified as definite or probable OOH-CA events than those in CPR + AED units (43% versus 55%, odds ratio 0.78, 95% confidence interval 0.57-1.07). The study retained sufficient power to permit a statistical analysis of the alternative hypothesis that the CPR + AED method results in twice as many survivors as a CPR-only approach. The result is critically dependent on the denominator used for calculating survival rates; but the analysis does not require a denominator as the numerators will have identical Poisson distributions (counts for rare events) under the null hypothesis since randomization distributes the risk of cardiac arrest evenly between the two arms.

CONCLUSION

Reported OOH-CA rates and survival rates vary widely, depending upon the definitions applied to events. Rigorous assessment of treatments applied to improve survival can be obscured by inappropriate definitions. Large-scale randomized interventions designed to improve survival from OOH-CA can be evaluated based upon the absolute numbers of patients surviving, rather than a change in the proportion surviving.

Prognostic Assessment of Patients With Acute Myocardial Infarction Treated With Primary Angioplasty

Background— The aim of this study was to create a practical score for risk stratification in patients with ST-segment elevation myocardial infarction (STEMI) treated with primary angioplasty and to assess the feasibility of early discharge in low-risk patients.

Methods and Results— A prognostic score was built according to 30-day mortality rates in 1791 patients undergoing primary angioplasty for STEMI. For the identified low-risk patients without any contraindication to early discharge, we estimated and compared the costs of conventional care (prolonged 24-hour hospitalization) with the costs of shifting the care from inpatient to outpatient setting (early discharge) between 48 and 72 hours. Independent predictors of 30-day mortality included in the score were age, anterior infarction, Killip class, ischemic time, postprocedural Thrombolysis In Myocardial Infarction (TIMI) flow, and multivessel disease. This score was able to identify a large cohort (73.4%) of low-risk (score ≤3) patients, with a good discriminatory capacity ( c statistic=0.907). The mortality rate was 0.1% at 2 days and 0.2% between 2 and 10 days in patients with a score ≤3. The incremental cost-effectiveness ratio for late discharge in low-risk patients was estimated at 1949.33. Therefore, this policy would save 1 life per 1097 low-risk patients, at additional costs of 194 933.33, in comparison with an early discharge policy.

Conclusions— This score is a practical and useful index for risk stratification after primary angioplasty for STEMI, with a significant impact on clinical decision-making and the related costs. It reliably identifies a large group of patients at very low risk, who may safely be discharged early after primary angioplasty.

Presentation, management, and outcome of out of hospital cardiopulmonary arrest: comparison by underlying aetiology

OBJECTIVE

To describe and compare presentation, management, and survival by aetiology of cardiopulmonary arrest.

DESIGN, SETTING, AND PATIENTS

A retrospective cohort study was undertaken of all 21 175 first out of hospital cardiopulmonary arrests in Scotland between May 1991 and March 1998.

MAIN OUTCOME MEASURE

Discharge alive from hospital.

RESULTS

Presumed cardiac disease accounted for 17 451 cases (82%), other internal aetiologies for 1814 (9%), and external aetiologies for 1910 (9%). Arrests caused by presumed cardiac disease had a better risk profile in terms of presence of a witness, bystander cardiopulmonary resuscitation, call-response interval, and use of defibrillation; 1265 (7%) of those who arrested from presumed cardiac disease were discharged alive, compared with only 77 (2%) of those with non-cardiac disorders (p < 0.001). Among those defibrillated, call-response interval was associated with survival following arrests from both presumed cardiac and non-cardiac causes (p < 0.001).

CONCLUSIONS

Out of hospital cardiopulmonary arrests from non-cardiac causes were associated with worse crude survival than arrests from cardiac causes. Improvements in call-response interval and basic life support skills in the community would improve survival irrespective of the aetiology and should therefore be encouraged.

An outcome study of out-of-hospital cardiac arrest using the Utstein template--a Japanese experience

Publication of the Utstein style template has made it possible to evaluate and compare national, regional, and hospital based Emergency Medical Services. This research was a national investigation to present outcome data for out-of-hospital cardiac arrest (OHCA) patients in Japan. 3029 OHCA patients who were transported to 10 Emergency and Critical Care Medical Center from November 1997 to April 1999 were recorded according to the Utstein style and the outcome evaluated by logistic regression analysis. Among 3029 OHCA patients, 109 were found dead. The remaining 2920 patients who underwent cardiopulmonary resuscitation (CPR) by emergency medical technicians (EMT) were included in this study. Among these patients, 1294 were considered of primary cardiac origin patients by the EMT and 722 of these patients suffered a witnessed cardiac arrest. Bystander CPR were performed in 28.4% of these witnessed patients and the discharge rate was 3.5% overall and 11.4% in witnessed VF/VT. Outcome analysis showed that a discharge rate in witnessed primary cardiac arrest was 30% in prehospital resuscitation which was 7.5 times higher than in-hospital emergency room resuscitation groups (4.0%). The longer the interval between an emergency telephone call and defibrillation, the lower the 1 month survival rate, which reached almost 0% at 30 min. Follow up evaluation after discharge revealed that the survival rate rapidly decreased from 24 h to 3 months, then became a plateau in primary cardiac patients was rapidly decreased from 24 h to 1 month, then became a near plateau in non-cardiac origin group. To improve the resuscitation rate in the prehospital phase, a prehospital medical control system should be developed with expansion of on scene techniques by Japanese paramedics such as tracheal intubation, administration of emergency drugs and early defibrillation with standing orders. Education and motivation of first responders will be needed and every effort should be concentrated on improving bystander CPR rate.

Community competence in cardiopulmonary resuscitation

The aim of this study was to determine community application of cardiopulmonary resuscitation (CPR) skills in an emergency, and, thus, assess the value of training programmes in raising community competence. A cross-sectional telephone survey of the Western Australian population was chosen randomly (n = 803). An urban sub-sample (n = 100) performed a practical demonstration of CPR skills using a simulated collapse scenario using a recording manikin as the victim. Performance was assessed by two observers using pre-determined criteria. Of all respondents, 64% had been trained in CPR. Practical and theoretical assessment scores were significantly better in trained versus untrained participants. The number of times a person was trained in CPR was more effective for retention and competence than time since last trained. Degree of training and theoretical competence were less in those aged over 65 years or with heart disease in the household. Theoretical competence poorly reflected practical performance in many tasks. This study provides a comprehensive database of CPR training and performance, and highlights future directions to ensure appropriate and cost-effective training. Specific factors to be addressed include increasing frequency of training, targeting of high-risk groups, simplification in teaching, and emphasising early activation of the emergency medical system.

Do health care professionals report sudden cardiac arrest better than laymen?

OBJECTIVE

To compare the emergency calls made by health care providers and by laymen reporting a non-traumatic cardiac arrest, and to evaluate the handling of these calls by dispatchers.

METHODS

The study was conducted prospectively over a 1-year period in 1996. The callers (N=328) where divided in to three groups based on profession: I, doctors and nurses (N=33); II, other health care providers (N=19); and III, laymen (N=276). Main outcome measures where the information given by the caller, use of the dispatching protocol, recognition of the cardiac arrest, and survival to hospital.

RESULTS

Doctors and nurses told the dispatcher spontaneously what had happened in 67% of the calls when total strangers to the patient told it in 72%. Group I gave no information about the vital signs in 24% of the calls, group II in 0% and group III in 6%. Of the 52 phone calls made by groups I and II, in six cases the patient was not in cardiac arrest, in four the patient had already irreversible signs of death and in four only transportation to another hospital was requested for a patient in cardiac arrest. Of the professionals calling, 49 (94%) were on duty at the time of the call. The cardiac arrest was recognized by the dispatcher in group I in 70%, in group II in 74% and in group III in 73%. There where no statistical differences between the groups.

CONCLUSIONS

Our data do suggest that health care professionals, excluding those in emergency medicine, are not better than laymen in evaluating an emergency situation correctly, and when the caller is a doctor or a nurse the dispatcher seems to trust the evaluation of the situation to be correct and rarely asks any clarifying questions about vital signs of the patient.

Cardiac arrest patients in an alpine area during a six year period

OBJECTIVE

The components of the 'chain of survival' remain the strongest pathway to save more people from out-of-hospital cardiac arrest. The 'Utstein Style' terminology has been applied to this study to evaluate survival in patients cared for by Emergency Medical Technicians--Defibrillation (EMT-D) and physicians in a rural alpine area.

METHODS

Over a 6-year period in a descriptive observational study with prospective data collection special efforts were made to identify weaknesses in the 'links' of our emergency cardiac care system considering the special geographical and legal aspects. Data from all emergency calls dispatched by the ambulance centre for patients with cardiac arrest were collected and are presented as a median and interquartile range.

RESULTS

We recorded 368 cardiac arrests and in 338 patients resuscitation was attempted. Ventricular fibrillation (VF) was observed in 118 patients (35%), of whom 13 (4%) were defibrillated by EMT-Ds and 105 (31%) by physicians. Response times were 1 (0,2) min to call, 8 (6-11) min to arrival of first tier and 16 (10-26) min to defibrillation. Restoration of spontaneous circulation was achieved in 54 (46%) VF-patients. In EMT-D vs. physician treated VF-patients 1 year survival was 1 (8%) versus 20 (19%).

CONCLUSION

With the exception of publications on avalanche victims and mountaineers, there are no reports of patients with out-of-hospital cardiac arrest in alpine areas. Response intervals and survival rate are not as poor as might be expected and are similar to metropolitan areas.

Resuscitation research: future directions and ethical issues

Cardiopulmonary resuscitation research is a vital area of research that has made significant contributions to medical care over the last several decades. Abundant information currently exists in the medical literature, as a result of research in the areas of cardiac arrest and outcomes, physiology of cardiac arrest, pharmacologic treatments, mechanical interventions, and societal and ethical issues. Despite numerous clinical trials demonstrating physiologic benefit of various interventions, few interventions have had as much impact on outcomes of cardiac arrest as have improvements in out-of-hospital response times and rapid availability of medical treatment. Although abundant information exists regarding physiologic aspects of resuscitation, relatively little information exists about ethical, psychological, and social aspects of resuscitation. In addition to attempts to improve outcomes of cardiac arrest, researchers should also strive to improve the experiences of patients and families involved. These realities provide future strategies and directions for the best use of resuscitation research resources; although physiologic and pharmacologic research will always have significant roles in the improvement of medical care, the rapid delivery of out-of-hospital care and ethical issues will be indispensable areas of research focus in the future.

Chain of survival: differences in early access and early CPR between policemen and high-school students

Immediate activation of the emergency medical service (EMS) and cardiopulmonary resuscitation (CPR) increases the incidence of return of spontaneous circulation and the number discharged from hospital. The American Heart Association (AHA) and the European Resuscitation Council describe CPR as an ordinate sequence of eight steps. The objectives of this study were to assess the general knowledge of EMS and CPR and to analyse the retention of the CPR steps 2 months after a Basic Life Support (BLS)-course conducted according to AHA standards. We studied two populations from the same geographical area, law enforcement agents (LEA), since they are often the first to intervene, and high school students (HSS) since they are more likely to participate in such courses. HSS were more responsive and receptive than LEA. In order to increase the retention of the sequence of CPR steps, the number of steps should be reduced and refresher courses should be included in training programmes. Early access and early CPR are still not completely effective in the geographical area studied.

One-year survival after out-of-hospital cardiac arrest in Copenhagen according to the 'Utstein style'

OBJECTIVE

To determine survival after out-of-hospital cardiac arrest (CA) in Copenhagen, according to the Utstein recommendations, and compare this with other emergency medical services systems.

DESIGN

Register-based cohort study.

SETTING

Copenhagen, population 465000, area 90 km(2).

PATIENTS

Consecutive group of patients with out-of-hospital CA occurring between January 1 1991 and December 31 1993, followed up via the hospital database systems.

MATERIALS

Two specially equipped advanced life support (ALS) units, staffed with an anaesthesiologist and a specially trained fireman, operating to support basic life support units.

RESULTS

Of 2225 patients who were unconscious without a pulse or breathing, 1461 were declared dead by the anaesthesiologist. Advanced cardiac life support was initiated in 764, 61 of which were of non-cardiac aetiology. The presumed aetiology was cardiac in 703: in 235 the event was unwitnessed, in 464 witnessed and in four the information was missing. Of 464 witnessed CA the initial rhythm was asystole in 72 cases, in 302 ventricular fibrillation (VF) or ventricular tachycardia (VT), and in 90 were in other rhythms. In these subgroups discharged rates were 5 (7%), 62 (21%) and 1 (1%), and 1-year survival rates were 4 (6%), 49 (16%) and 1 (1%), respectively. The median ALS call-response interval was 6 min.

CONCLUSIONS

Survival after CA is more likely if the collapse was witnessed and in patients with VF/VT of cardiac aetiology.

Cost effectiveness of early discharge after uncomplicated acute myocardial infarction

BACKGROUND

Reducing the length of hospitalizations can reduce short-term costs, but there are few data on the long-term clinical and economic consequences of early discharge.

METHODS

Using data from the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO-1) trial, we identified 22,361 patients with acute myocardial infarction who had an uncomplicated course for 72 hours after thrombolysis. Then, using a decision-analytic model, we examined the cost effectiveness of an additional day of hospitalization in this group. We defined incremental survival attributable to another day of monitored hospitalization, using Kaplan-Meier estimates to determine the rate of resuscitation after cardiac arrest between 72 and 96 hours. Lifetime survival curves for each group in the decision-analytic model were estimated from empirical one-year survival data from GUSTO-1. The costs of key hospital resources (e.g., room and monitoring) were derived from data in the GUSTO-1 cost-effectiveness analysis.

RESULTS

Of the patients with an uncomplicated course within 72 hours after thrombolysis, 16 had ventricular arrhythmias during the next 24 hours; 13 of these patients (81 percent) survived for at least 24 hours. On average, another 0.006 year of life per patient could be saved by keeping patients with an uncomplicated course in the hospital another day. At a cost of $624 for hospital and physicians' services, extending the hospital stay by another day would cost $105,629 per year of life saved. In sensitivity analyses, it was found that a fourth day of hospitalization would be economically attractive only if its cost could be reduced by more than 50 percent or if a high-risk subgroup could be identified in which the estimated survival benefit would be doubled.

CONCLUSIONS

Hospitalization of patients with uncomplicated myocardial infarction beyond three days after thrombolysis is economically unattractive by conventional standards.

In-hospital versus out-of-hospital presentation of life-threatening ventricular arrhythmias predicts survival: results from the AVID Registry. Antiarrhythmics Versus Implantable Defibrillators

OBJECTIVES

This study describes the outcomes of patients from the Antiarrhythmics Versus Implantable Defibrillators (AVID) Study Registry to determine how the location of ventricular arrhythmia presentation influences survival.

BACKGROUND

Most studies of cardiac arrest report outcome following out-of-hospital resuscitation. In contrast, there are minimal data on long-term outcome following in-hospital cardiac arrest.

METHODS

The AVID Study was a multicenter, randomized comparison of drug and defibrillator strategies to treat life-threatening ventricular arrhythmias. A Registry was maintained of all patients with sustained ventricular arrhythmias at each study site. The present study includes patients who had AVID-eligible arrhythmias, both randomized and not randomized. Patients with in-hospital and out-of-hospital presentations are compared. Data on long-term mortality were obtained through the National Death Index.

RESULTS

The unadjusted mortality rates at one- and two-year follow-ups were 23% and 31.1% for patients with in-hospital presentations, and 10.5% and 16.8% for those with out-of-hospital presentations (p < 0.001), respectively. The adjusted mortality rates at one- and two-year follow-ups were 14.8% and 20.9% for patients with in-hospital presentations, and 8.4% and 14.1% for those with out-of-hospital presentations (p < 0.001), respectively. The adjusted long-term relative risk for in-hospital versus out-of-hospital presentation was 1.6 (95% confidence interval [CI] 1.3-1.9).

CONCLUSIONS

Compared with patients with out-of-hospital presentations of life-threatening ventricular arrhythmias not due to a reversible cause, patients with in-hospital presentations have a worse long-term prognosis. Because location of ventricular arrhythmia presentation is an independent predictor of long-term outcome, it should be considered as an element of risk stratification and when planning clinical trials.

Long-term survival after out-of-hospital cardiac arrest: an 8-year follow-up

Between 1988 and 1994, 441 patients were successfully resuscitated outside hospital in the city of Rotterdam, of whom 276 (63%) were discharged from hospital alive. Long-term survival was studied amongst those who were discharged alive. The duration of follow-up averaged 6.71 years. A survival rate of 88% after 1 year, 81% after 3 years, 77% after 5 years and 73% after 7 years was found. After multivariate analysis, age, diagnosis and gender were found to be independent and significant predictors of survival. No significant difference in survival was found in patients who had been resuscitated by emergency personnel, physicians and bystanders. Patients who were still alive were sent a EuroQol-questionnaire. No differences in outcomes between the four groups were found. Since long-term prognosis after out-of-hospital resuscitation is satisfactory, learning programmes for resuscitation should be continued.

Ethical issues of resuscitation

There is a wide variety of ethical issues and dilemmas involving resuscitation, the act of restoring life to a patient in cardiorespiratory arrest. Decisions must be made rapidly and often must be based on suboptimal levels of information available at the time. Certain issues should be considered when one is making decisions in the resuscitation arena, including positive-aspects of resuscitation, not only the possibility of restoring life to the patient but also providing a sense of closure and resolution of guilt for the survivors. During and following resuscitative efforts, the psychologic and emotional well-being of the survivors should also be given close attention.

Pediatric cardiopulmonary resuscitation: a collective review

Little information is available about the effects of CPR in children, although it is known that the outcomes are dismal. Examples of unanswered questions include which advanced life support (ALS) procedures should be performed out-of-hospital, whether high-dose epinephrine improves survival, and the true prevalence of ventricular fibrillation as a presenting rhythm. Children differ from adults as to the cause and pathophysiology of cardiopulmonary arrest, but prehospital EMS and hospital resuscitation teams were initially designed for the care of adults. Because pediatric cardiopulmonary arrest is rare, prospective data are difficult to gather, and there are few large published studies. The purpose of this collective review was to review the current body of knowledge regarding survival rates and outcomes in pediatric CPR and, based on this review, to outline a course for future research.

Cardiopulmonary resuscitation: historical perspective to recent investigations

There are at least 300,000 cardiac arrests annually in the United States. Cardiopulmonary resuscitation (CPR) effectively restores hemodynamic stability, return of spontaneous circulation (ROSC), in 40% to 60% of arrests. Prolonged survival is significantly lower because of underlying illness and the postresuscitation syndrome, specifically central nervous system injury and left ventricular stunning after resuscitation. Prognostic variables have been shown to predict survival in multivariate analyses, but no models are sufficiently accurate to predict futility. End-tidal carbon dioxide has prognostic value and can measure the efficacy of CPR. Cardiac arrest outcomes will be most improved with public education and earlier initiation of resuscitative efforts, both Basic Life Support and Advanced Cardiac Life Support, notably defibrillation. Active compression-decompression and interposed abdominal compressions improved ROSC in prospective randomized trials; abdominal compressions have also been shown to increase survival to hospital discharge. Despite 30 years of research, CPR is now performed much as it was initially. Further research into the mechanisms of cardiac arrest, development of predictive models, and improved means to improve cardiac output and survival are needed.

Randomised trial of magnesium in in-hospital cardiac arrest. Duke Internal Medicine Housestaff

BACKGROUND

The apparent benefit of magnesium in acute myocardial infarction, and the persistently poor outcome after cardiac arrest, have led to use of magnesium in cardiopulmonary resuscitation. Because few data on its use in cardiac arrest were available, we undertook a randomised placebo-controlled trial (MAGIC trial).

METHODS

Patients treated for cardiac arrest by the Duke Hospital code team were randomly assigned intravenous magnesium (2 g [8 mmoles] bolus, followed by 8 g [32 mmoles] over 24 h; 76 patients) or placebo (80 patients). Only patients in intensive care or general wards were eligible; those whose cardiac arrest occurred in emergency, operating, or recovery rooms were excluded. The primary endpoint was return of spontaneous circulation, defined as attainment of any measurable blood pressure or palpable pulse for at least 1 h after cardiac arrest. The secondary endpoints were survival to 24 h, survival to hospital discharge, and neurological outcome. Analysis was by intention to treat.

FINDINGS

There were no significant differences between the magnesium and placebo groups in the proportion with return of spontaneous circulation (41 [54%] vs 48 [60%], p = 0.44), survival to 24 h (33 [43%] vs 40 [50%], p = 0.41), survival to hospital discharge (16 [21%] vs 17 [21%], p = 0.98), or Glasgow coma score (median 15 in both).

INTERPRETATION

Empirical magnesium supplementation did not improve the rate of successful resuscitation, survival to 24 h, or survival to hospital discharge overall or in any subpopulation of patients with in-hospital cardiac arrest.

Unwitnessed out-of-hospital cardiac arrest: is resuscitation worthwhile?

STUDY OBJECTIVE

To determine the epidemiology of unwitnessed out-of-hospital cardiac arrest and the factors associated with survival after resuscitation using the Utstein style data collection.

METHODS

We conducted a prospective cohort study in a 525,000-population city served by a single EMS system comprising a tiered response with physicians in the field. We studied consecutive unwitnessed out-of-hospital cardiac arrests that occurred between January 1, 1994, and December 31, 1995. We determined survival from cardiac arrest to discharge from hospital and the factors associated with survival.

RESULTS

Of the 809 patients for whom resuscitation was considered, 205 (25.3%) had sustained unwitnessed arrests. Cardiac origin of arrest was verified in 52% of cases. The most common noncardiac causes of arrest were trauma, intoxication, near-drowning, and hanging. In 150 patients (73.2%) the presenting rhythm was asystole, in 28 (13.6%) it was pulseless electrical activity, and in 27 (13.2%) it was ventricular fibrillation. Resuscitation was attempted in 162 cases, 59 (36.4%) of whom demonstrated return of spontaneous circulation; 45 (27.8%) were hospitalized alive, and 8 (4.9%) were discharged. The survivors represented 6.7% of all out-of-hospital cardiac arrest survivors during the study period. Survival was most likely if patients presented with pulseless electrical activity; none of the patients with asystole of cardiac origin survived. Sex (P = .032), age (inverse relationship, P = .0004), scene of collapse (P = .042), and interval from call receipt to arrival of first responders (P = .004) were associated with survival. In a logistic-regression model, near-drowning remained an independent factor of survival (odds ratio, 15.5; 95% confidence interval, 1.2 to 200). A routine priority dispatching protocol differentiated cardiac arrest patients with survival potential from those who already had irreversible signs of death.

CONCLUSION

This survey shows that survival after unwitnessed out-of-hospital cardiac arrest is unlikely with an initial response of basic life support alone. Withdrawal of resuscitation should be considered if an adult victim of unwitnessed cardiac arrest is found in asystole and the arrest is of obvious cardiac origin.

Cardiac arrest witnessed by prehospital personnel: intersystem variation in initial rhythm as a basis for a proposed extension of the Utstein recommendations

STUDY OBJECTIVE

To test the hypothesis that intersystem variation in initial rhythm among EMS-witnessed arrests is of sufficient magnitude to warrant standardization of survival by creation of an Utstein-style denominator of EMS-witnessed ventricular fibrillation (VF).

METHODS

We conducted a planned subset analysis of a prospective observational cohort study of consecutive EMS-witnessed adult cardiac arrests occurring in New York City and meeting Utstein entry criteria. The primary outcome measure was intersystem variation in frequency of EMS-witnessed VF in New York City compared with that in other EMS systems. Secondary outcome measures were variations in survival after EMS-witnessed VF arrests and overall survival after all EMS-witnessed arrests.

RESULTS

Intersystem variation showed a threefold difference in the frequency of EMS-witnessed VF (24% in New York City versus 77% in Scotland; 99% confidence interval [CI] for 53% difference, 43% to 63%; P < 10(-7), a twofold difference in survival after EMS-witnessed VF (25% in NYC versus 48% in King County, WA; 99% CI for 23% difference, 6% to 39%; P < .002), and a fourfold difference in survival after all EMS-witnessed arrests (9% in New York City versus 35% in King County; 99% CI for 26% difference, 18% to 34%; P < 10(-7).

CONCLUSION

The marked variation in frequency of initial rhythm in EMS-witnessed arrests suggests that a modified Utstein denominator of EMS-witnessed VF would facilitate more uniform intersystem comparison of survival in this unique cohort. However, even after adjustment for initial rhythm, large residual intersystem survival differences remain unexplained.

Outcome of out-of-hospital cardiorespiratory arrest in south Glamorgan

During 138 weeks an emergency medical service (EMS) of mixed skill-level attempted to resuscitate 954 patients from prehospital cardiac arrest (883 attempts per million population per year); 75% of the arrests were of cardiac cause. This paper is one of the first analyses from europe to use the 'Utstein template' to report outcomes of such arrests. In cases where an arrest rhythm could be recorded, 38.4% were ventricular fibrillation (VF), 45.5% were asystolic, and the remainder were either electromechanical dissociation or respiratory arrests. Using univariate analysis factors associated with a greater likelihood of survival include the presence of a witness, bystander-initiated cardiopulmonary resuscitation (CPR), early CPR and VF as the arrest rhythm. Twenty of 155 cases (13%) survived where VF arrest was witnessed by non-EMS personnel.