Results of attempted cardiopulmonary resuscitation of patients dying suddenly outside the hospital in Reykjavik and the surrounding area, 1976-1979

The Ontario Prehospital Advanced Life Support (OPALS) Study: rationale and methodology for cardiac arrest patients

The Ontario Prehospital Advanced Life Support Study represents the largest prehospital study yet conducted, worldwide. This study will involve more than 25,000 cardiac arrest, trauma, and critically ill patients over an 8-year period. The study will evaluate the incremental benefit of rapid defibrillation and prehospital Advanced Cardiac Life Support measures for cardiac arrest survival and the benefit of Advanced Life Support for patients with traumatic injuries and other critically ill prehospital patients. This article describes the OPALS study with regard to the rationale and methodology for cardiac arrest patients.

Characteristics of prehospital cardiac arrest patients in Japan and determinant factors for survival

Two hundred forty-seven consecutive patients who had prehospital cardiac arrest and were transferred to a municipal hospital were studied to elucidate the characteristics of these patients and to investigate factors for improving the survival rate among prehospital cardiac arrest patients. Detailed information on 130 patients with cardiac etiology was analyzed: 110 were confirmed dead in the emergency department (group A); 14 survived less than 1 week (group B); 6 survived longer than 1 week (group C). Only one patient received cardiopulmonary resuscitation (CPR) from a bystander, and none received electrical defibrillation before arriving at hospital because, at the time, emergency personnel were not allowed to perform advanced life support (ALS) in Japan. The three characteristics for better prognosis after prehospital cardiac arrest were found to be as follows: being witnessed on collapse, receiving prompt ALS, and ventricular fibrillation on arrival at hospital. The survival rate would have been higher if more lay people could have performed CPR and if emergency unit personnel had been allowed to perform ALS.

ACD versus standard CPR in a prehospital setting

BACKGROUND

Animal and human studies in cardiac arrest demonstrate significant improvements in systolic blood pressure, coronary perfusion pressure and total brain and myocardial blood flow with active compression-decompression (ACD) cardiopulmonary resuscitation (CPR). The results of recent studies in patients with out-of-hospital cardiac arrest and use of ACD-CPR are non-uniform and require supplementation.

METHODS

In a retrospective non-randomised design, 152 adult patients with prehospital cardiac arrest, not caused by trauma or hypothermia, were studied. Compressions were performed according to the recommendations of the American Heart Association. Three ACD devices were assigned to seven rescue units changing monthly. Study end-points were the rates of return of spontaneous circulation (ROSC), admission to hospital, survival at 24h, hospital discharge and neurologic outcome.

RESULTS

70 (46%) patients underwent standard (STD) CPR and 82 (54%) patients were treated with ACD-CPR. Both groups were comparable with regard to age, sex, witnessed cardiac arrests, bystander CPR, cause of arrest, time intervals, number of defibrillations, and total amount of epinephrine. No significant differences in outcome could be found: 20 patients (29%) who received STD-CPR, and 14 patients (17%) who underwent ACD-CPR survived to hospital discharge. Neither at other end-points nor in any subgroups could any significant differences be discovered. Patients regaining ROSC showed a significant difference in favour of STD-CPR for the end-points of hospital admission, 24-h survival and hospital discharge.

CONCLUSION

No significant differences in hospital discharge and neurological outcome were found between STD-CPR and ACD-CPR.

Effectiveness of emergency medical services for victims of out-of-hospital cardiac arrest: a metaanalysis

STUDY 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.

Family response to out-of-hospital death

OBJECTIVE

To better understand the perceptions, needs, and responses of family members after an out-of-hospital death.

METHODS

Over an 18-month period, phone interviews were conducted using a structured interview schedule modified from a similar study of survivors of in-hospital death. Subjects included 31 survivors of urban out-of-hospital deaths attended by paramedics from one ambulance company. Subjects were eligible if paramedics had arrived and death had been determined at the scene without transport. Survivors were interviewed 11 to 15 months after the death (mean = 12 months) to evaluate how well they coped with their loss, how they managed the experience of their loved ones' out-of-hospital deaths, and their feelings and beliefs about their loved ones' not being transported to a hospital.

RESULTS

None of the survivors believed their loved ones should have been transported to a hospital, and only one believed that something more could have been done for the individual. Although many of the survivors had suspected their loved ones had died, 64% had been informed of the death by emergency medical technicians (EMTs) or firefighters. Most thought the EMTs had informed them in a professional (81%) and gentle/supportive manner (74%). Some (29%) still had unanswered questions about the death, but most (58%) were adjusting well and no one had a "poor" adjustment.

CONCLUSION

In this small sample, survivors of out-of-hospital death were generally satisfied with the care their loved ones had received. None of the survivors believed their loved ones should have been transported to the hospital. They also believed the paramedics had been supportive and met their needs at the time of death. It appears that paramedics may be able to meet the needs of a patient's survivors by terminating out-of-hospital resuscitation efforts on the patient.

Methodology-dependent variation in documentation of outcome predictors in out-of-hospital cardiac arrest

OBJECTIVE

To identify variation in outcome predictor documentation in out-of-hospital cardiac arrest associated with two different methods of data collection: concurrent questioning of personnel following a resuscitation attempt and archival report review.

METHODS

All patients > or = 18 years old who had out-of-hospital cardiac arrests, verified using the New York City 911 telephone system, between October 1, 1990, and April 1, 1991, were eligible for inclusion. The authors reviewed the first 200 cases of presumed primary cardiac arrest involving a resuscitation attempt among 3,243 consecutive ambulance call reports for cardiac arrest occurring during the study period. This archival data set was compared with data for the same 200 cases gathered through direct interview of field personnel by trained paramedics. The two data sets had been compiled independently by different individuals, using the same data collection instrument, which conformed to the Utstein template.

RESULTS

Comparison of the data obtained from ambulance records with the data obtained from interviews of prehospital personnel revealed several areas of variance. Of note was a significantly lower proportion of bystander-witnessed ventricular fibrillation (VF) in the data set gathered from written reports (7% vs 18%; 95% CI for the difference 4-18%; p = 0.001).

CONCLUSION

differences in methods of collection of out-of-hospital cardiac arrest data are associated with a more than twofold variation in the reported incidences of witnessed cardiac arrests manifesting as VF. Methodology-dependent variation in this important "denominator" may produce substantially different estimates of survival within the same cohort of patients.

Methodology for data collection to study prehospital cardiac arrest in New York City: the PHASE methodology. PreHospital Arrest Survival Evaluation Group

STUDY OBJECTIVE

To describe an effective methodology for the investigation of prehospital cardiac arrest in large cities.

DESIGN

Observational cohort study.

SETTING

New York City emergency medical services system.

PARTICIPANTS

All cardiac arrests dispatched by the 911 system between October 1, 1990, and March 31, 1991.

INTERVENTIONS

Trained paramedics performed immediate postarrest interviews with prehospital and hospital care providers using a standardized data collection instrument.

RESULTS

Of 3,239 consecutive, confirmed cardiac arrests in which resuscitation was attempted, 2,329 (72%) were of cardiac etiology. Information was sought for 15 of the 17 core events and times recommended by the Utstein Consensus Conference Data were obtained in more than 98% of cases for all except one of these core events and times. One core time yielded data in 96% of cases. All patients were followed until death or discharge home. None were lost to follow-up.

CONCLUSION

Concurrent, interactive acquisition of prehospital cardiac arrest data in a large urban setting captured over 98% of the core data recommended for completion of the Utstein template. This methodology may be a suitable means of investigating prehospital cardiac arrest in large cities.

Predictors of early and late survival after out-of-hospital cardiac arrest in which asystole was the first recorded arrhythmia on scene

BACKGROUND

A large proportion of patients who suffer out-of-hospital cardiac arrest have asystole as the initial recorded arrhythmia. Since they have a poor prognosis, less attention has been paid to this group of patients.

AIM

To describe a consecutive population of patients with out-of-hospital cardiac arrest with asystole as the first recorded arrhythmia and to try to define indicators for an increased chance of survival in this population.

SETTING

The community of Gothenburg.

PATIENTS

All patients who suffered out-of-hospital cardiac arrest during 1981 to 1992 and were reached by our emergency medical service (EMS) system and where cardiopulmonary resuscitation (CPR) was attempted.

RESULTS

In all there were 3434 cardiac arrests of which 1222 (35%) showed asystole as the first recorded arrhythmia. They differed from patients with ventricular fibrillation by being younger, including more women and having a longer interval between collapse and arrival of the first ambulance. In all 90 patients (7%) were hospitalized alive and 20 (2%) could be discharged from hospital. Independent predictors for an increased chance of survival were: (a) a short interval between the collapse and arrival of the first ambulance (P < 0.001) and the time the collapse occurred (P < 0.05). Initial treatment given in some cases with adrenaline, atropine and tribonate were not associated with an increased survival.

CONCLUSIONS

Of all the patients with out-of-hospital cardiac arrest, 35% were found in asystole. Of these, 7% were hospitalized alive and 2% could be discharged from hospital. Efforts should be made to improve still further the interval between collapse and arrival of the first ambulance.

Predicting survival from out-of-hospital cardiac arrest: a graphic model

STUDY OBJECTIVE

To develop a graphic model that describes survival from sudden out-of-hospital cardiac arrest as a function of time intervals to critical prehospital interventions.

PARTICIPANTS

From a cardiac arrest surveillance system in place since 1976 in King County, Washington, we selected 1,667 cardiac arrest patients with a high likelihood of survival: they had underlying heart disease, were in ventricular fibrillation, and had arrested before arrival of emergency medical services (EMS) personnel.

METHODS

For each patient, we obtained the time intervals from collapse to CPR, to first defibrillatory shock, and to initiation of advanced cardiac life support (ACLS).

RESULTS

A multiple linear regression model fitting the data gave the following equation: survival rate = 67%-2.3% per minute to CPR-1.1% per minute to defibrillation-2.1% per minute to ACLS, which was significant at P < .001. The first term, 67%, represents the survival rate if all three interventions were to occur immediately on collapse. Without treatment (CPR, defibrillatory shock, or definitive care), the decline in survival rate is the sum of the three coefficients, or 5.5% per minute. Survival rates predicted by the model for given EMS response times approximated published observed rates for EMS systems in which paramedics respond with or without emergency medical technicians.

CONCLUSION

The model is useful in planning community EMS programs, comparing EMS systems, and showing how different arrival times within a system affect survival rate.

Incidence of cardiac arrest: a neglected factor in evaluating survival rates

STUDY OBJECTIVES

To add to our understanding of survival rates in out-of-hospital cardiac arrest studies, we examined the incidence of cardiac arrest in the published literature. We specifically estimated if incidence rates are uniform between communities and if any relationship exists between incidence and the reported survival rates.

DESIGN

A retrospective study of nearly 100 cardiac arrest peer-reviewed articles from 1970 to 1989 was performed to identify reports that included rates for incidence and survival or provided sufficient data for the calculation of these rates.

MEASUREMENTS AND MAIN RESULTS

We were able to obtain reported or calculated incidence and survival rates for 20 communities. Statistical analysis was performed to compare incidence rates between communities and examine the relationship across these 20 studies between incidence rates and reported survival rates. Incidence rates ranged significantly from 35.7 to 128.3 per 100,000, with a mean of 62. Survival rates ranged significantly from 1.6% to 20.7%. Incidence rates in these communities were negatively related to survival rates; that is, as the incidence rate increased, the survival rate decreased. We determined the regression curve that describes this inverse relationship. This nomogram can be used to identify survival/incidence rate combinations that are significantly above or below average.

CONCLUSION

The marked variations in incidence and inverse relationship between incidence and survival could be due to true variation in risk among the populations reported (ie, some populations may be older or sicker than others). Also, different research methodologies may create artifactual differences among studies as standards for designing studies, terminology, and reporting data have not been uniform. Therefore, these findings may reflect methodological differences and true epidemiological differences among communities. Future reports should include a method, such as an incidence/survival nomogram, to analyze survival rates while taking into account the community incidence rate of cardiac arrest. Further analysis of incidence and survival is necessary to improve intersystem comparisons, a prerequisite to sound decisions about cardiac arrest treatment, health policy, and allocation of resources.

Survival rates from out-of-hospital cardiac arrest: recommendations for uniform definitions and data to report

Survival rates for out-of-hospital cardiac arrest vary widely among locations. We surveyed the definitions used in published studies of out-of-hospital cardiac arrest. Data from 74 studies involving 36 communities showed survival rates ranging from 2% to 44%. There were five different case definitions and 11 different definitions of survivors. The absence of uniform definitions prevents meaningful intersystem comparisons, prohibits explorations of hypotheses about effective interventions, and interferes with the efforts of quality assurance. The most satisfactory numerator for a survival rate appears to be survival to hospital discharge; the most appropriate denominator appears to be witnessed adult cardiac arrest of presumed heart disease etiology, with ventricular fibrillation as the initial identified rhythm. Proposed definitions for the data emergency medical services systems should report as they examine their cardiac arrest survival rates are presented.

Cardiac arrest and resuscitation: a tale of 29 cities

Published reports of out-of-hospital cardiac arrest give widely varying results. The variation in survival rates within each type of system is due, in part, to variation in definitions. To determine other reasons for differences in survival rates, we reviewed published studies conducted from 1967 to 1988 on 39 emergency medical services programs from 29 different locations. These programs could be grouped into five types of prehospital systems based on the personnel who deliver CPR, defibrillation, medications, and endotracheal intubation; the five systems were three types of single-response systems (basic emergency medical technician [EMT], EMT-defibrillation [EMT-D], and paramedic) and two double-response systems (EMT/paramedic and EMT-D/paramedic). Reported discharge rates ranged from 2% to 25% for all cardiac rhythms and from 3% to 33% for ventricular fibrillation. The lowest survival rates occurred in single-response systems and the highest rates in double-response systems, although there was considerable variation within each type of system. Hypothetical survival curves suggest that the ability to resuscitate is a function of time, type, and sequence of therapy. Survival appears to be highest in double-response systems because CPR is started early. We speculate that early CPR permits definitive procedures, including defibrillation, medications, and intubation, to be more effective.

Prehospital cardiac arrest--a critical analysis of factors affecting survival

During a 10-year period, 5631 cardiac arrests were treated in our paramedic system. In all, 4216 resuscitations were attempted, of which 533 (12.6%) resulted in saves, defined as hospital discharges. Patients presenting with an initial rhythm of coarse ventricular fibrillation or ventricular tachycardia were found to have significantly increased save rates in comparison to those presenting with an initial arrest rhythm of asystole/fine ventricular fibrillation or electromechanical dissociation (P less than or equal to 0.01). When controlling for witnessed arrest, 303 of 1905 (15.9%) of all witnessed arrests were saves vs. 230 of 2311 (10%) of unwitnessed arrests (P less than or equal to 0.01). Witnessed bystander/first responder external cardiac compression- cardiopulmonary resuscitation (ECC-CPR) was found not to influence save rate. One hundred eighty-one of 1248 bystander/first responder witnessed arrests (14.5%) who had external ECC-CPR initiated before paramedic advanced life support arrival were saves, compared with 38 of 252 (15.1%) who had no ECC-CPR initiated until paramedic arrival; this was not statistically significant. Advanced life support response times in saved patients with witnessed cardiac arrests were analyzed. Ninety-five percent of all saves had a response time of less than 10 min. We conclude that, when evaluating the effectiveness of CPR, the variables of witnessing of arrest, presenting arrest rhythm, and respective response times must be controlled or analyzed.

Advanced cardiac life support in the prehospital setting: the Reykjavik experience

Since 1982 a mobile emergency care unit (emergency ambulance) manned by a physician has been operated in Reykjavik. During 1982-1986 there were 138 attempted resuscitations in sudden cardiorespiratory arrest from cardiac causes. Twenty-four patients (17%) were discharged home, all but one without mental impairment. Seventy-three patients presented with ventricular fibrillation, 21 (29%) of which were discharged. The mean ambulance response time was 5 min. Bystanders initiated cardiopulmonary resuscitation (CPR) in 40 cases (29%) which significantly improved the outcome. In witnessed arrests, 19 of 36 patients (53%) with bystander-initiated CPR were discharged compared to 5 of 62 patients (8%) where CPR awaited the arrival of the ambulance team. These results are comparable to those obtained in larger metropolitan areas. In small urban areas the size of Reykjavik (population of 110,000), an advanced and efficient prehospital care can be organized as an extension of the emergency departments role.

Influence of emergency medical services systems and prehospital defibrillation on survival of sudden cardiac death victims

This article reviews the influence of emergency medical systems and prehospital defibrillation on survival of sudden cardiac death. The historical perspective and epidemiologic considerations of prehospital sudden cardiac death are highlighted. Factors predictive of successful resuscitation and impact of community activity on sudden death are discussed. Influences of emergency medical services on outcome of prehospital cardiac arrest are reviewed, with emphasis on the role of dispatchers, emergency medical technicians, and paramedics. The recent emergence of prehospital automatic defibrillation by emergency medical technicians, first responders, and lay persons is discussed in depth, as it has great potential to positively influence outcome of prehospital sudden cardiac death.

A computerized prospective audit of cardiopulmonary resuscitation in the accident and emergency department

A prospective survey of cardiopulmonary resuscitation is in progress in the Accident and Emergency Department of the Royal Hallamshire Hospital. During the 12 months from January 1985 to January 1986, 123 cardiac arrests were treated in the accident department. Ninety of these arrests occurred outside the hospital; nine of these patients survived to leave hospital. Of the 33 people arresting in the department, 10 survived to leave hospital. The causes of death are presented.

Bystander/first responder CPR: ten years experience in a paramedic system

The effectiveness of bystander CPR recently has been challenged. We undertook a ten-year retrospective review of our prehospital experience with witnessed cardiorespiratory arrest to ascertain save rates in patients receiving and not receiving CPR before paramedic advanced life support (ALS). Traumatic and poisoning arrests and children less than 18 years old were excluded. A total of 1,905 patients presenting to a paramedic system from November 1, 1973, to October 31, 1983, were bystander-witnessed arrests and attempted paramedic resuscitations. Four hundred five paramedic-witnessed arrests were excluded. One hundred eighty-two of 1,248 (14.6%) who had CPR initiated before paramedic ALS arrival were saves, compared to 38 of 252 (15%) who had no CPR initiated until paramedic arrival (P = NS). A save was defined as a patient discharged from the hospital. The respective save rates for coarse ventricular fibrillation were 148 of 628 (23.6%) (CPR before paramedic arrival) vs 35 of 151 (CPR delayed until paramedic arrival) (23.2%); electromechanical dissociation (EMD), 11 of 209 (5.3%) vs 0 of 38; asystole, 19 of 401 (4.7%) vs 3 of 61 (4.9%); and ventricular tachycardia, four of ten (40%) vs 0 of two. In this prehospital system, bystander/first responder CPR was found not to improve hospital discharge rates except in patients with initially documented rhythm of EMD.

Guidelines for discontinuing prehospital CPR in the emergency department--a review

We provide information that we believe should allow the establishment of rational guidelines for discontinuing, with physician supervision, unsuccessful prehospital CPR. Goldberg has advocated that CPR be terminated only after evidence of brain or cardiac death has persisted for more than one hour of adequately applied advanced CPR. This recommendation was made for inhospital resuscitation and does not reflect the limited capabilities of basic and advanced CPR techniques to sustain life outside the hospital. In addition, White and associates have demonstrated that after resuscitation from prolonged cardiac arrest, cerebral cortical blood flow is reduced severely. This state of hypoperfusion may last up to 18 hours. Because this condition can result in extensive neurologic damage, it may explain the poor survival rates after prolonged resuscitation. We propose that CPR be terminated in the ED when, despite adequate rescue attempts (intubation, defibrillation, IV medications, CCCM en route) by those responding at the scene of cardiac arrest, intrinsic cardiac activity has not been achieved in patients brought to the hospital with asystole or bradyarrhythmia. Additionally patients who have had advanced prehospital CPR for more than 45 minutes without generation of any intrinsic cardiac activity are not resuscitatable by current standard techniques, and CPR may be discontinued. These criteria must not be used for victims of hypothermia before a core temperature of 35 C to 36.1 C is achieved by active core rewarming during CPR. The available data suggest that if these criteria are implemented, many unproductive hospital-based resuscitative efforts can be eliminated without jeopardizing potential survivors.(ABSTRACT TRUNCATED AT 250 WORDS)

The problem of cardiac arrest in the community

Out-of-hospital cardiac arrests constitute 350,000 cases yearly in the United States and 60,000 in the United Kingdom. Prompt resuscitation (CPR) by lay persons and fast defibrillation by paramedics have had epidemiologic consequences on both sides of the Atlantic. In Seattle there are 20.6 and in Brighton 10.0 long-term life-saves yearly per 100,000 persons. In Piedmont Virginia, coronary deaths fell 16% for persons 30-69 years old and 25% for those of all ages; prehospital life-saves accounted for 23% and 8% of each respective reduction. Since CPR by lay persons now triples the long-term survival rate when coupled with prehospital defibrillation, favorable benefit-to-cost ratios can be effected by adding advanced life support and citizen CPR to an extant ambulance system. Meticulous direct and indirect medical control by the physician assures the highest quality of CPR and early cardiac care (ECC). Diagnostic procedures like electro-provocation identify high-risk patients. Changes of behavior and diet, new drugs, new operations, and external and implantable automated devices reduce sudden deaths. In the future, automated defibrillation by first responders and trained lay persons (including members of families of high-risk patients) should increase the number of early survivors who become candidates for long-term therapy with drugs, operations, and devices.