[Clinical studies on emergency medicine. An application oriented classification, its planning and realization]

Clinical studies are usually conceived of as controlled randomized trials, as retrospective patient statistics or as single case reports. However, such a classification is too narrow and overlooks many other forms of study designs. This review, therefore, offers a more encompassing and practical classification of clinical studies for the field of emergency medicine. Randomized controlled trials fulfill scientific criteria at the highest level (gold standard): comparison, repeatability, objective measurement. At the same time, randomized trials also have to comply with demanding ethical criteria and must be justifiable in the individual patient. Therefore, comparable uncertainty with regard to the superiority of the treatment options under investigation is a sine qua non. In addition to randomized trials, six other groups of clinical trials have the potential to solve scientific questions in emergency medicine: observational studies, decision analysis, meta analysis, public health care studies, case reports and descriptive summary statistics and studies on ethical problems. This variability in trial designs calls for a clinically oriented methodologist; the concept and institutionalization of theoretical surgery has been a response to this demand. All study types in this review are illustrated by examples in emergency medicine. Literature for advanced reading in particular trial methodologies can be found in the reference list. A checklist summarizes all elements for designing and conducting randomized trials in emergency medicine. All clinical trials striving for a high standard of quality--whether randomized or not--depend on the following prerequisites:professional organization, time effort, a supportive social environment and a scientific culture.