Annals of emergency medicine
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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. ⋯ 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.
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When the abdomen is compressed manually in counterpoint to the rhythm of chest compression, in the performance of interposed abdominal compression-CPR, artificial circulation is approximately doubled in animal experiments and in electronic models of the circulatory system. These studies suggest that external manual compression of the abdominal aorta acts like an intra-aortic balloon pump to increase aortic pressure, whereas external manual compression of the abdominal veins acts to prime the right heart and pulmonary vessels before the next chest compression. ⋯ Several clinical studies of this technique have shown promising results including improved hemodynamics, resuscitation success, and survival. The history of interposed abdominal compression-CPR research suggests a number of principles that may be useful in the development of other new methods for the management of cardiac arrest, including the virtues of vigorously pursuing a new idea suggested by serendipitous observations, developing and refining a working hypothesis as to pathophysiologic mechanisms, working in interdisciplinary groups, refining a novel technique in stages as experience is gained, and recognizing the need for staged phase 1, 2, and 3 clinical trials in the context of the approximately ten-year gestation period from laboratory inspiration to clinical practice.
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There is no better place to test life-saving resuscitation interventions than in the prehospital setting. Patients rarely survive cardiac arrest if resuscitation techniques have failed before leaving the scene. ⋯ Most important, by reinforcing standardized care, rigidly scrutinized trials improve patient care, regardless of the effect of the study intervention. The success of productive EMS research centers requires routine communication between hospital and EMS administrators and their medical directors, designation of mutually acceptable data collectors who guarantee confidentiality, reciprocal exchange of study data provided as educational seminars to the hospitals, commitments to support the budget requests of an EMS program and appropriate system modifications, inclusion of EMS personnel in study design from the very beginning, prospective education of the medical community and media before protocol implementation, an authoritative grassroots medical director, and a paramedic supervisor system.
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Patients who suffer an in-hospital cardiac arrest represent a neglected and underutilized resource for resuscitation research. There exists an unwritten, but widely held, belief among resuscitation researchers that the in-hospital arrest population is unsuitable for resuscitation research because it is composed mostly of patients whose cardiac arrest is the terminal event of a fatal illness. Despite the large numbers of hospitalized patients on whom cardiac resuscitation is attempted each year, there are few reports and even less true research devoted to this clinical problem. This article, which is intended to be provocative, reviews and summarizes the existing literature on in-hospital resuscitation from cardiac arrest, considers the advantages of resuscitation research in this setting, and concludes with a challenge to resuscitation researchers.
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To enhance comparability in reports on survival from out-of-hospital cardiac arrest, an international task force recently developed a set of guidelines for uniform terminology, definitions, and data collection for outcome research on cardiac arrest--the Utstein style. Because the data collection recommended is limited to information available through emergency medical services systems, the potential for bias in comparisons of cardiac arrest outcomes remains. By expanding data collection to include the identification of all cases of cardiac arrest in the community, including patients who do not present for care by an emergency medical services system, a population-based approach can be achieved. We review the strengths and limitations of both emergency medical services-based and population-based data collection to assess outcomes of cardiac arrest, outline practical steps required to implement a population-based approach, and suggest that extension of the Utstein style guidelines to include all cardiac arrest cases within a defined population is needed to minimize potential bias in comparisons of cardiac arrest outcomes across communities or over time.