A multidisciplinary system to respond to the needs of severely injured patients from the time of injury through the provision of definitive care. Such systems call not only on the health care system, but also on public safety, communication, and other community resources. Several studies have published criteria for a trauma system, based on the recommendations of the American College of Surgeons (ACS). In general, such systems should have (1) a lead agency with authority to designate trauma centers, (2) a formal process for trauma center designation, (3) the use of ACS standards for trauma centers, (4) the use of a neutral, out-of-area team for making the trauma center designation, (5) limiting the number of trauma centers, in recognition of the superior care and lower cost provided by highly specialized and active centers, (6) the use of written patient categorization and triage criteria for bypassing non-trauma center hospitals, (7) ongoing information and monitoring systems, including a trauma registry, and (8) state-wide availability. It is reported that by 1993 only 5 states had complete trauma systems. Trauma systems are cited as models which could well be followed in the design of regionalized systems for such conditions as cardiac surgery, organ transplantation, and high-risk neonatal care.