Original ContributionFollow-up of 514 consecutive patients with cardiopulmonary arrest outside the hospital*
During the years 1974 to 1976, 514 patients with prehospital cardiopulmonary arrest were brought to the Hennepin County Medical Center (HCMC) Emergency Department. Of these, 344 patients (67%) were either dead on arrival or died in the emergency department despite efforts at resuscitation. The remaining 170 patients were admitted to the coronary care unit. Eighty-seven patients (51%) died in the coronary care unit, primarily from uncontrolled rhythm disturbances and/or cardiogenic shock. The remaining 83 patients (16% of the total group, 49% of those admitted to the hospital) were discharged alive from HCMC. In this group, 49 patients of the 83 long-term survivors were ambulatory with full mental function when discharged. The remaining 34 patients were transferred to chronic care facilities for medical treatment of on-going problems. Of the 49 ambulatory patients, satisfactory data for follow-up was obtained on 47. Their mortality rate was 15% in the first year and 50% in the second, primarily from sudden death syndrome.
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Cited by (47)
How accurately can the aetiology of cardiac arrest be established in an out-of-hospital setting? Analysis by " Concordance in Diagnosis Crosscheck Tables"
2011, ResuscitationCitation Excerpt :On the other hand, 10.9% of patients who were assumed to have non-cardiac aetiology were reclassified to the cardiac aetiology group (Fig. 2). This shows that any analysis that focuses only on a selected aetiology group (i.e., cardiac aetiology) while omitting other possible aetiologies, as has been used in some studies,36–40 can introduce a bias into the results. In this study the overall numbers of cases with a particular diagnosis made by rescue team physicians and later by hospital physicians/pathologists were close.
Several previous studies have focused on establishing the cause of cardiac arrest (CA) during cardiopulmonary resuscitation (CPR) provided in an out-of-hospital setting.
To analyze the ability of professional advanced life support providers to correctly establish the aetiology of cardiac arrest during out-of-hospital CPR.
A retrospective cohort study analysing 211 cases of out-of-hospital cardiac arrest.
The aetiology assumed by out-of-hospital physicians was compared with the diagnosis that was later established by clinicians or pathologists.
Cases were sorted into five diagnostic groups and the overall diagnostic concordance was 74.4% (157 of 211 cases). The cardiac aetiology was presumed in 132 out of 211 patients and confirmed in 135 out of 211 patients.
However, an analysis of individual cases of the cardiac causes of cardiac arrest revealed diagnostic matches in only 112 cases. Acute myocardial infarction (AMI) or pulmonary embolism (PE), both of which represent cases that can be potentially influenced by thrombolytic therapy, were presumed in 74 (53 + 21) and confirmed in 97 (77 + 20) cases, however with individual diagnostic matches in only 55 cases.
This study demonstrates the importance of analysing concordance in presumed and definitive diagnosis of individual cases, since an overall comparison in a cohort of cases may be highly misleading. It introduces the method of the crosscheck table for visualization and comparison of presumed and final diagnoses. The two alternative approaches of inclusion rule for applying the thrombolytic therapy in out-of-hospital care were discussed with regard to the recent TROICA study.
Prediction rules for estimating neurologic outcome following out-of-hospital cardiac arrest
2004, ResuscitationBackground: No valid model has been developed to predict survival following out-of-hospital cardiac arrest. The purpose of this study was to develop a prediction model for meaningful survival following out-of-hospital cardiac arrest using variables available during resuscitation. Methods: This was a retrospective cohort study. Consecutive adult cardiac arrest patients were studied between 1994 and 2001. Variables included age, sex, race/ethnicity, arrest location, whether the arrest was witnessed, initial rhythm, whether CPR was performed, patient downtime, paramedic response time, survival to hospital discharge, and Glasgow Coma Score (GCS) at hospital discharge. Classification and Regression Tree analysis was used to develop decision rules to predict meaningful survival, as defined by the patient’s discharge GCS. Results: Of the 754 patients, 16 (2%) survived with a GCS ≥ 13, 15 (2%) survived with a GCS = 14, and 5 (0.7%) survived with a GCS = 15. The decision rule for survival with a GCS ≥ 13 incorporated whether the arrest was witnessed and the patient’s age, resulting in a negative predictive value (NPV) of 99.8%. The rule for survival with a GCS ≥ 14 incorporated the initial arrest rhythm, whether the arrest was witnessed, and the patient’s age, resulting in a NPV of 99.6%. The rule for survival with a GCS = 15 incorporated only the interval between collapse and the initiation of life support, resulting in a NPV of 99.8%. Conclusions: This study reports decision rules for potential meaningful survival following out-of-hospital cardiac arrest with high NPVs for each. Future studies need to be performed to prospectively validate these models.
Contexto: Não foi desenvolvido nenhum modelo válido para prever a sobrevida após paragem cardı́aca extra-hospitalar. O objectivo deste estudo foi desenvolver um modelo predictivo para sobrevida significativa após paragem cardı́aca extra-hospitalar utilizando variáveis disponı́veis durante a reanimação. Métodos: Este foi um estudo retrospectivo agrupado. Foram estudados doentes consecutivos com paragem cardı́aca entre 1994 e 2001. As variáveis incluı́ram a idade, sexo, raça/etnia, local da paragem, testemunhada ou não, ritmo inicial, RCP ou não, tempo de paragem, tempo de resposta pamédica, sobrevida a alta hospitalar e Escala de Coma de Glasgow (GCS) na alta hospitalar. A classificação e análise por árvore de regressão foram utilizadas para desenvolver regras de tomada de decisão para prever sobrevida significativa, conforme definido pela GCS na alta. Resultados: Dos 754 doentes, 16 (2%) sobreviveram com uma GCS ≥ 13, 15 (2%) sobreviveram com uma GCS = 14 e 5 (0.7%) sobreviveram com uma GCS = 15. A regra de decisão para sobrevida com uma GCS ≥ 13 incorporava se a paragem tinha sido testemunhada e a idade do doente, resultando num valor predictivo negativo (VPN) de 99.6%. A regra para sobrevida com um GCS = 15 incorporava apenas o tempo de inconsciência, resultando num VPN de 99.8%. Conclusões: Este estudo relata regras de decisão para sobrevida significativa potencial após paragem cardı́aca extra-hospitalar com elevado VPN para cada uma. São necessários estudos para validar prospectivamente estes modelos.
Antecedentes: No se ha desarrollado un modelo válido para predecir la sobrevida después de un paro cardiaco extrahospitalario. El propósito de este estudio fue desarrollar un modelo para predecir una sobrevida significativa después de un paro cardiaco extrahospitalario usando variables disponibles durante la resucitación. Métodos: Este fue un estudio de cohorte retrospectivo. Se estudiaron casos consecutivos de paro cardiaco, ocurridos entre 1994 y 2001. Las variables incluyeron edad, sexo, raza/etnia, localización del paro, si fue presenciado, ritmo inicial, si se realizó CPR, momento de colapso, tiempo de respuesta de los paramédicos, sobrevida al alta, escala de coma de Glasgow (GCS) al momento del alta. Se usó la clasificación y análisis de árbol de regresión para desarrollar unas reglas de decisiones para predecir sobrevida significativa, como se definió por el GCS al alta. Resultados: de los 754 pacientes, 16 (2%) sobrevivieron con un GCS ≥ 13, 15 (2%) sobrevivieron con un GCS = 14, y 5 (0.7%) sobrevivieron con GCS = 15. La regla de decisión para sobrevida con GCS ≥ 13 incorpora si acaso el paro fue presenciado y la edad del paciente, resultando con un valor de predicción negativo (NPV) de 99.8%. La regla para sobrevida con GCS ≥ 14 incorpora el ritmo inicial del paro, si el paro fue presenciado, la edad del paciente, resultando en un NPV de 99.6%. La regla para sobrevida con GCS = 15 incorpora solamente el tiempo de colapso, resultando en un NPV de 99.8%. Conclusiones: Este estudio reporta reglas de decisión para sobrevida significativa después de un paro cardı́aco extrahospitalario con alto NPV para cada uno. Deben realizarse futuros estudios para validad prospectivamente estos modelos.
A cumulative meta-analysis of the effectiveness of defibrillator-capable emergency medical services for victims of out-of-hospital cardiac arrest
1999, Annals of Emergency MedicineStudy objective: More than 1,000 patients experience sudden cardiac arrest each day. Treatment for this includes cardiopulmonary resuscitation (CPR_ and emergency medical services (EMS) that provide CPR-basic life support (BLS), BLS with defibrillation (BLS-D), or advanced life support (ALS). Our previous systematic review of treatments for sudden cardiac arrest was limited by suboptimal data. Since then, debate has increased about whether bystander CPR is effective or whether attention should focus instead on rapid defibrillation. Therefore a cumulative meta-analysis was conducted to determine the relative effectiveness of differences in the defibrillation response time interval, proportion of bystander CPR, and type of EMS system on survival after out-of-hospital cardiac arrest.
Methods: A comprehensive literature search was performed by using a priori exclusion criteria. We considered EMS systems that provided BLS-D, ALS, BLS plus ALS, or BLS-D plus ALS care. A generalized linear model was used with dispersion estimation for random effects.
Results: Thirty-seven eligible articles described 39 EMS systems and included 33, 124 patients. Median survival for all rhythm groups to hospital discharge was 6.4% (interquartile range, 3.7 to 10.3). Odds of survival were 1.06 (95% confidence interval [Cl], 1.03 to 1.09; P<.01) per 5% increase in bystander CPR. Survival was constant if the defibrillation response time interval was less than 6 minutes, decreased as the interval increased from 6 to 11 minutes, and leveled of after 11 minutes (P<.01). Compared with BLS-D, odds of survival were as follows: ALS, 1.71 (95% Cl, 1.09 to 2.70; P=.01); BLS plus ALS, 1.47 (95% Cl, 0.89 to 2.42; P=.07); and BLS with defibrillation plus ALS, 2.31 (95% Cl, 1.47 to 3.62; P<.01.)
Conclusion: We confirm that greater survival after sudden cardiac arrest is associated with provision of bystander CPR, early defibrillation, or ALS. More research is required to evaluate the relative benefit of early defibrillation versus early ALS.
Out-of-hospital cardiac arrests: An 8-year New York City experience
1996, American Journal of Emergency MedicineA retrospective study was conducted to determine the outcome of out-of-hospital cardiac arrests by one prehospital system in New York City from January, 1986, through December, 1993. The results were recorded consistent with the Utstein Style. Of 481 attempted patient resuscitations 406 were of cardiac etiology, with 382 patients having arrested prior to EMS arrival; their overall survival rate was 2.1% (8/382). Cardiac arrests were witnessed in 246 patients. Of the witnessed arrest patients found in ventricular fibrillation (96/246), the overall survival rate was 7.3% (7/96). Of the 7 survivors who were discharged from the hospital, 71.4% (5/7) had a good cerebral performance/good overall performance. Of 24 patients who arrested in the presence of EMS, the survival rate was 12.5% (3/24). This study confirms a poor survival rate for patients suffering out-of-hospital cardiac arrests in New York City.
Effectiveness of emergency medical services for victims of out-of-hospital cardiac arrest: A metaanalysis
1996, Annals of Emergency MedicineStudy objective: To determine the relative effectiveness of differences in response time interval, proportion of bystander CPR, and type and tier of emergency medical services (EMS) system on survival after out of hospital cardiac arrest. Methods: We performed a comprehensive literature search, excluding EMS systems other than those of interest (systems of interest were those comprising one tier with providers of basic life support [BLS] or advanced life support [ALS] and those comprising two tiers with providers of BLS or BLS-defibrillation followed by ALS), patient population of fewer than 100 cardiac arrests, studies in which we could not determine the total number of arrests of presumed cardiac origin, and studies lacking data on survival to hospital discharge. Metaanalysis using generalized linear model with dispersion estimation for random effects was then performed. Results: Increased survival to hospital discharge was significantly associated with tier (P<.01), response time interval (P <.01), and bystander CPR (P=.04). A significant interaction was detected between response time interval and bystander CPR (P=.02). For the studies analyzed, survival was 5.2% in a one-tier EMS system or 10.5% in a two-tier EMS system. A 1-minute decrease in mean response time interval was associated with absolute increases in survival rates of .4% and .7% in a one-tier and two-tier EMS systems, respectively. Conclusion: Increased survival to hospital discharge may be associated with decreased response time interval and with the use of a two-tier EMS system as opposed to a one-tier system. The data available for this analysis were suboptimal. Policymakers need more methodologically rigorous research to have more reliable and valid estimates of the effectiveness of different EMS systems. [Nichol G, Detsky AS, Stiell IG, O'Rourke K, Wells G, Laupacis A: Effectiveness of emergency medical services for victims of out-of-hospital cardiac arrest: A metaanalysis. Ann Emerg Med June 1996;27:700-710.]
Heart disease is the most common cause of death in the United States.1 Such deaths are often due to cardiac arrest, the sudden cessation of cardiac mechanical activity manifested by the absence of a detectable pulse, unresponsiveness, and lack of breathing.2 Emergency medical services (EMS) systems have evolved into multifaceted advanced cardiac life support systems involving CPR, defibrillation, artificial ventilation, intubation, and administration of medication.
Controversy exists about the effectiveness of different methods of emergency cardiac care because of wide variation in reported survival among centers3, ranging from 0%4 to 44%.5 This variation may be attributable to differences in the type of EMS system, proportion of victims receiving bystander CPR, response time intervals of providers, or geography of the city in question.6 Furthermore, different approaches to reporting survival make comparison of studies difficult.6, 7, 8 A consensus conference has offered guidelines for uniform reporting of results to facilitate comparison of results.2
The purpose of this analysis was to estimate the relative effectiveness of the type and tier of an EMS system, unit response time interval of providers, and rate of bystander CPR on survival after out-of-hospital cardiac arrest. Using a protocol developed a priori, we performed a metaanalysis based on conventional techniques.9, 10 The protocol comprised selection criteria for the primary studies, definitions of the primary endpoints, and an analysis plan.11 The metaanalysis was part of a larger cost-effectiveness analysis of improvements to EMS systems for out-of-hospital cardiac arrest. The results of the cost-effectiveness analysis are reported elsewhere.12
Definitions of terms The organization of an EMS system may vary both in the degree of training of the health care providers, as well as in the number of vehicles responding to a medical emergency. No universally accepted nomenclature exists for categorizing EMS systems, and some terms may have different meanings for different people.
To facilitate clarity and understanding, the following terms are defined. Emergency health care providers vary in the degree of their training and may or may not transport patients to the hospital. Basic life support (BLS) providers administer oxygen and CPR to victims of cardiac arrest. Providers of BLS with defibrillation (BLS-D) defibrillate patients using automated or manual defibrillators. Finally, advanced life support (ALS) providers are trained to perform endotracheal intubation and to administer IV medications. BLS or BLS-D level care may be provided by emergency medical technicians (EMTs) in ambulances or by firefighters in pump vehicles or vans. Generally, ALS care is only provided by EMTs in ambulances. These personnel are referred to by others as "paramedics."
The team that responds to a cardiac arrest in a given city may be part of a one-tier or two-tier EMS system. In a one-tier EMS system, a single provider and vehicle type responds to medical emergencies. In a two-tier system, two types of providers and/or vehicles respond. The vehicles may include ambulances, which respond from ambulance bases; or pump vehicles or vans, which respond from fire stations. In two-tier EMS systems, BLS providers (first tier) usually arrive more quickly because more generally are serving a community. In American cities with two-tier EMS systems, the second responding providers (second tier) have ALS capability. About 75% of the American urban population is served by a two-tier rather than by a one-tier EMS system.14
In this analysis we considered five configurations of EMS systems: (1) one tier with BLS providers, (2) one tier with BLS-D providers, (3) one tier with ALS providers, (4) two tiers with BLS followed by ALS (BLS + ALS) providers, and (5) two tiers with BLS-D followed by ALS (BLS-D + ALS) providers.
A peer-training model for instruction of basic cardiac life support
1995, ResuscitationThis study evaluates a peer-training model for cardiopulmonary resuscitation (CPR) instruction for laypersons. Forty-one Norwegian factory employees were trained in CPR and given instructor training. These first trainees then trained 311 co-workers. These employees then trained 873 family members and associates at home. The reference group consists of employees in a Massachusetts commercial hotel trained in seven American Red Cross (ARC): Adult CPR classes. The Norwegian home trainees learned CPR using a cardboard training manikin and were trained by Norwegian factory employees who had learned CPR from co-workers. Trainees were evaluated using skill sheets and a Laerdal Skillmeter™ manikin. The performance of the Norwegians trained at home by peers did not differ from that of the ARC: Adult CPR trainees in six skills of the initial sequence of CPR. The home trainees outperformed the ARC: Adult CPR trainees in the proportion of compressions delivered correctly (P = 0.032) and ventilations delivered correctly (P = 0.015). Peer training may provide CPR instruction comparable to training in CPR classes at lower cost and with potential to reach new population segments.
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Presented at the annual ACEP/EDNA Scientific Assembly in San Francisco, November, 1977.