Short- and long-term effects of emergency medicine sonography on formal sonography use: a decade of experience.

OBJECTIVES: It has been reported that use of formal sonographic studies by departments of radiology initially increases after inception of an emergency medicine (EM) sonography training program, but there are no data on whether this trend continues as the training program matures. The purpose of this study was to evaluate the effect of an ongoing EM sonography program on formal sonography use after more than a decade of experience. METHODS: This retrospective, computer-assisted review compared emergency department (ED) abdominal sonographic studies ordered in the 3 years before inception of an EM sonography program (1992-1994) with those ordered in the 8 years after its inception (1995-2002). To determine the relative change, all abdominal sonograms ordered by ED physicians were compared with equivalent outpatient formal sonograms by all other physicians in the hospital. The study site is a community teaching hospital with a current ED census of 50,000. RESULTS: In the initial 4 years (1995-1998), the number of formal studies increased significantly in both absolute numbers (annual mean, 95 versus 162; P < .002) and as a percentage of all outpatient sonograms ordered at the institution (5.1% versus 8.5%; P < .0001). However, in the following 4 years (1999-2002), the absolute number of formal studies remained constant but decreased when adjusted for an increased ED census. Emergency department-ordered formal studies also decreased as a percentage of all sonograms ordered (5.1% versus 4.1%; P = .002). CONCLUSIONS: Emergency department use of formal sonography services increases with the introduction of ED sonography but decreases markedly as the program matures.