Cardiac arrest in Stockholm with special reference to the ambulance organization

A geographic information system simulation model of EMS: reducing ambulance response time

Response time is a very important factor in determining the quality of prehospital EMS. Our objective was to model the response by Israeli ambulances and to offer model-derived strategies for improved deployment of ambulances to reduce response time. Using a geographic information system (GIS), a retrospective review of computerized ambulance call and dispatch logs was performed in two different regional districts, one large and urban and the other rural. All calls that were pinpointed geographically by the GIS were included, and their data were stratified by weekday and by daily shifts. Geographic areas (polygons) of, at most, 8 minutes response time were simulated for each of these subgroups to maximize the timely response of calls. Before using the GIS model, mean response times in the Carmel and Lachish districts were 12.3 and 9.2 minutes, respectively, with 34% and 62% of calls responded within 8 minutes. When ambulances were positioned within the modeled polygons, more than 94% of calls met the 8-minute criterion. The GIS simulation model presented in this study suggests that EMS could be more effective if a dynamic load-responsive ambulance deployment is adopted, potentially resulting in increased survival and cost-effectiveness.

Effect of bystander cardiopulmonary resuscitation in out-of-hospital cardiac arrest patients in Sweden

BACKGROUND

Information from the Swedish Cardiac Arrest Registry was used to investigate: (a) The proportion of patients suffering an out-of-hospital cardiac arrest who were given bystander cardiopulmonary resuscitation (B-CPR). (b) Where and by whom B-CPR was given. (c) The effect of B-CPR on survival.

METHOD

a prospective, observational study of cardiac arrests reported to the Swedish Cardiac Arrest Registry. Analyses were based on standardised reports of out-of-hospital cardiac arrests from ambulance organisations in Sweden, serving 60% of the Swedish population. From 1983 to 1995 approximately 15-20% of the population had been trained in CPR.

RESULTS

Of 9877 patients, collected between January 1990 and May 1995, B-CPR was attempted in 36%. In 56% of these cases, the bystanders were lay persons and in 25% they were medical personnel. Most of the arrests took place at home (69%) and only 23% of these patients were given B-CPR in contrast to cardiac arrest in other places where 53% were given CPR. Survival to 1 month was significantly higher in all cases that received B-CPR (8.2 vs. 2.5%). The odds ratio for survival to 1 month with B-CPR was in a logistic regression analysis 2.5 (95% CI 1.9-3.1).

CONCLUSIONS

In Sweden, the willingness and ability to perform B-CPR appears to be relatively widespread. More than half of B-CPR was performed by laypersons. B-CPR resulted in a two to threefold increase in survival.

Cardiac arrest in Saudi Arabia: a 7-year experience in Riyadh

All out-of-hospital and Emergency Department (ED) cardiac arrests treated at a tertiary care hospital in Riyadh, Saudi Arabia, from 1989 through 1995 were studied. Of patients arresting out-of-hospital, 3.0% received bystander cardiopulmonary resuscitation (CPR), 9.1% had some prehospital CPR, 12.1% were transported via ambulance, and 13.6% had ventricular fibrillation (VF) on ED arrival. In the witnessed arrests (80%), the estimated interval from arrest to initiation of CPR was 21.1 +/- 14.7 min. None of these variables was shown to influence outcome. Survival to hospital discharge from out-of-hospital arrest was 5.1% for adults and 7.4% for children; all had poor neurologic outcome. For patients arresting in the ED, an initial rhythm of ventricular tachycardia (VT) or VF was strongly correlated with survival. Survival from ED arrest was 30.4% in adults, 42.9% in children; all but one had normal neurologic outcome. These results are similar to those reported from large cities and EDs elsewhere. The unique set of variables influencing out-of-hospital care and transportation in Riyadh are discussed, and potential areas for improvement are noted.

A comparison of nursing implications for elder care in Sweden and the United States

The number of elderly are increasing at a rapid rate in both Sweden and the United States. Despite differences in governance, size, and health care systems, the two countries share similar problems and, perhaps, similar responses to care of aging persons. International educational exchange of successful interventions can promote better delivery of nursing care in both countries.

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.

Characteristics of midsized urban EMS systems

Emergency medical services (EMS) systems in 25 midsized cities (population, 400,000 to 900,000) are described. Information describing EMS system configuration and performance was collected by written and telephone surveys with follow-ups. Responding cities provide either one- or two-tier systems. In a one-tier system, an advanced life support (ALS) unit responds to and transports all patients who use 911 to activate the system. Three types of two-tier systems are identified. In system A, ALS units respond to all calls. Once on scene, an ALS unit can turn a patient over to a basic life support (BLS) unit for transport. In system B, ALS units do not respond to all calls; BLS units may be sent for noncritical calls. In system C, a nontransport ALS unit is dispatched with a transporting BLS unit. For ALS calls, ALS personnel join BLS personnel for transport. Overall, cities staff an average of one ambulance per 51,223 population. One-tier systems average one ambulance per 53,291 compared with two-tier systems, which average one ambulance per 47,546. In the two-tiered system B, the average ALS unit serves 118,956 population. In the 60% of cities that use a one-tier system, one ALS unit serves 58,336 (P less than .0005). Overall, the code 3 response time for all cities is an average of 6.6 minutes. The average response time of two-tier systems is 5.9 minutes versus 7.0 minutes for one-tier systems (.05 less than P less than .1). These data suggest that the two-tiered system B allows for a given number of ALS units to serve a much larger population while maintaining a rapid code 3 response time.

Clinical experience with three different defibrillators for resuscitation of out of hospital cardiac arrest

Three defibrillators, one manual and two different semiautomatic, were prospectively compared during a one year period for out-of-hospital use by ordinary ambulance personnel with short additional training. Eighty-three cardiac arrest patients were treated with one of two different semiautomatic defibrillators and 26 by an ordinary manual defibrillator. Twenty-nine were found in ventricular fibrillation. Five of these patients were successfully resuscitated and admitted for further hospital care, two survived to be discharged home. The semiautomatic defibrillators were found to be accurate in ECG interpretation, sensitivity and specificity was 100%, respectively, and both were equally effective in defibrillation. There were no differences in conversion rate or in the clinical outcome between the three defibrillators tested. Both semiautomatic defibrillators tested seemed to be safe, reliable and cost-effective. The low survival rate found is most certainly due to a long ambulance delay.

One year's experience of early defibrillation in Stockholm

The effects of resuscitation on patients who died suddenly out of hospital were evaluated after the introduction of early defibrillation performed by ambulance personnel using semi-automatic defibrillators. Resuscitation attempts were initiated in 548 patients during the 1-year study period. Mean ambulance delay was 7.5 min, 22% of the cardiac arrest patients had received bystander cardiopulmonary resuscitation (CPR). Sensitivity and specificity for the semi-automatic defibrillator in the interpretation of ventricular fibrillation was found to be 97 and 100% respectively. Only 28 (14%) of the 206 defibrillated patients regained circulation and were admitted for further hospital care. Only three survived to be discharged. Among the 342 patients in whom defibrillation was not indicated, 16 (5%) regained circulation and were admitted for further hospital care and one (0.3%) survived to be discharged. Semi-automatic defibrillators seem reliable, safe and inexpensive; however, the isolated addition of defibrillation to basal ambulance service seems to be inadequate in Stockholm. We need to evaluate what further resources are of importance to guarantee a successful outcome.

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.