Evidence-based performance measures for emergency medical services systems: a model for expanded EMS benchmarking.

There are few evidence-based measures of emergency medical services (EMS) system performance. In many jurisdictions, response-time intervals for advanced life support units andresuscitation rates for victims of cardiac arrest are the primary measures of EMS system performance. The association of the former with patient outcomes is not supported explicitly by the medical literature, while the latter focuses on a very small proportion of the EMS patient population andthus does not represent a sufficiently broad selection of patients. While these metrics have their place in performance measurement, a more robust method to measure andbenchmark EMS performance is needed. The 2007 U.S. Metropolitan Municipalties' EMS Medical Directors' Consortium has developed the following model that encompasses a broader range of clinical situations, including myocardial infarction, pulmonary edema, bronchospasm, status epilepticus, andtrauma. Where possible, the benefit conferred by EMS interventions is presented in the numb...