The Present
State of EMS
Research
Appeals for Advancement
EMS research is still in an early stage of maturation. A concerted effort to improve the scant scientific knowledge that serves as the basis for EMS practice is now mandatory.1,52 There has been a strong plea for improving the science within the field.53 The leaders of the Future of Emergency Medicine Research conference, sponsored by the Emergency Medicine Foundation, the Society for Academic Emergency Medicine, and the Association for Academic Chairs of Emergency Medicine, emphasized the need for individual and program commitment to the process of advancing research in emergency medicine. The conference report called for the necessary resources to enhance emergency medicine research through training, academia, funding, national support, multi-center research and development of new outcome measures.54
The Society for Academic Emergency Medicine EMS Task
Force published a paper in 1999 entitled
EMS Systems: Foundations for the Future, which called for the specialty of
emergency medicine to foster the continued development of EMS administration,
education, and research.52
The report pointed out, “The benefits of prehospital care never have been
demonstrated scientifically in many medical and surgical conditions. The time
has come to prove the value of field care and determine the most cost-effective
and medically sound treatments.”55
Peer Review
Journals
Several peer-review medical journals devoted to EMS are now in publication including Prehospital Emergency Care and Prehospital and Disaster Medicine. In addition, general emergency medicine journals, including Annals of Emergency Medicine, now contain sections devoted to EMS research. There are also subspecialty journals within emergency medicine, such as Pediatric Emergency Care and the Air Medical Journal, that publish material related to EMS and effectively reach an audience involved in at least some aspect of prehospital care of patients. The emergence of these journals holds an important position in the history of EMS. Their existence shows that EMS research is valuable to the readers of those publications.
Methodological Constraints and Concerns
Although the science of EMS has advanced, many concerns remain. Most of the problems are not very different than issues with which other fields of medicine have struggled. For example, there are not enough controlled clinical trials of new treatments for patient problems encountered by EMS professionals.
One methodological concern in EMS research is that the best outcome measures for various study questions are not clear.55 While survival may be an appropriate outcome measurement for sudden cardiac arrest, it would not be a meaningful outcome measurement for studies of minor trauma or respiratory distress because almost all patients will survive independent of any EMS intervention. Further, appropriate measurements of pediatric patient outcomes are sometimes different from those that are commonly used for adults.33
Current Literature in EMS
Several reviewers have evaluated the quality and quantity of EMS research over the last 30 years. Figure 1 shows an appraisal of the number of EMS related manuscripts published each year since 1965. The data in the figure are the result of an extensive search of multiple National Library of Medicine (NLM) research databases including PubMed and CINAHL. Although the number of EMS publications is not vast, the volume has been increasing steadily over the years at a respectable rate. Since 1970, the quantity of published EMS literature increased at a rate of approximately 200 articles per decade. The increase is likely due to increased awareness of the need for study in this area and also the appearance of several new journals dedicated to the specialty. If this growth rate remains constant, about 900 articles will be published in the year 2010.
There
have been many pleas to increase the number of clinical trials,56,57
and some have made eloquent points about the dangers inherent in the existence
of so few methodologically sound studies.27
Concern for the lack of scientific support for many pre-hospital interventions,
lack of uniform reporting methods, monitoring of outcomes and adverse effects
invokes the need for reexamination of EMS practice.52,58,59
While randomized controlled trials may be the gold standard for clinical studies, they are not appropriate for every question. For example, randomized trials are not appropriate for studies of harm, prognosis, or diagnostic devices.60,61 Randomized controlled trials can also be more challenging to implement in systems and educational settings. Indeed, very little educational research utilizes randomized-controlled designs.62
Although the body of published EMS literature is growing steadily, there is much concern about the substance of the material. In a recent review of the EMS literature published between 1985 and 1994, the most frequently used study design was the case series, which accounted for 44 percent of the publications. The majority of EMS studies published during that ten-year period (53%) were retrospective in nature.59
Figure 2 shows the results of an analysis conducted for
the National EMS Research Agenda project in which the NLM designated study type
was used to classify the 9,232 identified EMS related citations published
between 1966 and 2000. These categorizations are estimates, as not all studies
included a design designation. Despite this limitation in the analysis, it
remains apparent that the overwhelming majority of the published EMS literature
is not research reports but rather historical articles, editorials, consensus
development pieces, biographies, monographs, or guidelines.
Of those study types recognized as “research”, reviews (n=593; 6% of total)
reigned over clinical trials (n=331; 4%) and meta-analyses (n=15; 0.1%).
Evaluated on the basis of the strength of the study design, the majority of EMS
studies published in peer-reviewed journals use unpersuasive methodology. The
bulk of the published research can be characterized by its overwhelming
propensity to use simple descriptive methods and retrospective techniques.
With the understanding that randomized clinical trials may not always be the most appropriate design for scientific validation of prehospital treatments or system changes, the number of randomized trials conducted has been used as a surrogate marker for the level of sophistication in research. With this limitation in mind, the proportion of randomized trials out of all the clinical investigations published in EMS has been reported to range between 1%27, 5%63and 15%.59 As a point of reference, the proportion of randomized trials published in the entire specialty of emergency medicine has not changed much over the years, increasing from 10% in 1983, to 12% in 1989, and reaching 15% by 1997.64 This proportion is thought to be similar to the proportion of randomized trials estimated to exist in published internal medicine literatures.65 Appendix F of this document lists published randomized or pseudo-randomized clinical trials conducted in the EMS setting from 1966 through 2000 that could be identified by the writing team.
Research Domains
There are three domains within the spectrum of EMS research: clinical, systems, and educational. Clinical research involves the study of direct patient care activities. Systems research explores the effects of varying EMS system designs and operational methods on resource utilization. Educational research examines the appropriate methods for preparing prehospital care providers.
While each domain can be approached independently, researchers must recognize the interactions between the three areas. Teaching a paramedic to apply a splint ultimately translates into a patient care practice: immobilizing a fracture. Determining the appropriate clinical use of narcotics for pain management ultimately becomes a systems issue: securing and tracking controlled substances.
Clinical Research
To date, investigators with little formal research training and minimal funding or other resources have contributed the substance of the literature in prehospital emergency care. Thus, most published research addresses the most austere questions involving single clinical interventions or health issues. Answers to major EMS issues such as cost-effectiveness, resource utilization, efficacy of field therapies, and injury prevention are conspicuous by their absence from the literature. In addition, as in other areas of medicine, there is little research demonstrating effective methods to improve patient safety in EMS by reducing medical errors.
Despite the absence of evidence for the efficacy of almost all field interventions, progress is occurring in several areas. The Ontario Prehospital Advanced Life Support (OPALS) Study is the largest prehospital study ever conducted. It is enrolling more than 25,000 cardiac arrest, trauma, and critically ill patients over an 8-year period (1994-2002). The OPALS study uses a rigorous controlled methodology and a large sample size, and it is designed to measure the benefit in survival and morbidity that results from the introduction of prehospital ALS programs to communities of different sizes.25,26,66 While prehospital clinical studies of that magnitude have not been completed in the United States, some complex, well designed studies have been successfully implemented and completed. A clinical trial of the use of high dose epinephrine67 and the pediatric intubation study from Los Angeles18 are notable examples.
Systems Research
In 1995, a systems analysis framework was suggested in order to accurately study the complex and interrelated questions that characterize EMS.68 Systems analysis research models are more commonly employed in disciplines such as engineering, economics, and epidemiology where they are used to evaluate complex questions, often involving computer simulation and mathematical models such as nonlinear or multivariate analysis.69,70 In the publication, EMS Systems: Foundations For The Future, members of the SAEM EMS Task Force reviewed the unique aspects of systems-based questions and suggested a shift from the traditional EMS quality assurance model to one based on improving overall system performance.52
An example of systems research is the investigation that showed providing defibrillators to police officers to augment EMS response to sudden cardiac arrest improved survival to hospital discharge.71,72 Another example demonstrated that pain is routinely under-treated in patients with extremity fractures.73 Although partially a clinical issue, certain components of the EMS system, such as the level of training for the caregivers and the procedures for replenishing medication supplies, contributed significantly to the problem. Researchers should approach EMS as a system of care, rather than as an isolated process.
Education
There have been a handful of studies designed to analyze the suitability of the curricula and training practices to the actual provision of services by EMTs.74-78 There seems to be very little in the way of actual evaluation of the relationship between curricula, educational methods and practice. For example, the core competencies expected of paramedics vary widely across the country, suggesting a lack of agreement on the appropriate set of skills for an entry-level paramedic.
An example of educational research is the analysis to
determine whether the advanced airway training module in the EMT-Basic National
Standard Curriculum assured competency in performing endotracheal intubation, a
complex skill. Two investigations found that most EMT-Basic level providers did
not achieve skill competency when asked to perform endotracheal intubation on
actual patients in the field.79,80
