A model for capacity planning of a comprehensive integrated information system for hospitals and clinics

Appropriate system sizing is essential to ensuring a reasonable computer response time for end users. A model is discussed that describes the type and number of interactions between user terminals and printers and the central processor for a comprehensive, integrated medical information system. The system modeled includes support to inpatient and outpatient order entry and results reporting for clinical services; registration; admission, disposition, and transfer; patient appointing; pharmacy, clinical laboratory, and radiology; medical record management; and electronic messages. Originally developed for use in benchmark testing of comprehensive systems designed for military hospitals and clinics, the model has been generalized to be applicable to other systems and settings. Results are presented for a routine busy day in a 200-bed teaching hospital providing extensive outpatient services, and a large free-standing clinic. The model results can be applied to several facets of system planning, including sizing of the central processor and communications network, determining the optimal number of storage devices and user devices, and fine tuning the user interface.