provider. To maintain constant availability of the system, HELP has been developed to run on special fault-tolerant computers.
The clinical information system at Beth Israel Hospital in Boston, Massachusetts, was developed by the Harvard Medical School's Center for Clinical Computing and has been in continuous use and evolution for more than a decade (Bleich and Slack, 1989).14 The system at Brigham and Women's Hospital in Boston, also from the Clinical Computing Center, was modeled after Beth Israel's system and required approximately four years to develop. More than 800 and more than 1,250 on-line terminals currently operate at Beth Israel and Brigham and Women's hospitals, respectively (Safran et al., 1989). One outstanding attribute of these systems is their extensive use by clinicians and other members of the health care team. At Beth Israel during an average week, for example, 742 departmental and laboratory workers entered or corrected information in computer-based patient records 137,526 times (Bleich et al., 1989). Similarly, during an average week, 532 physicians, 893 nurses, 59 medical students, and 253 health assistants used the computer terminals to examine patient information.
In addition to reporting results, these systems provide other capabilities to clinicians: scheduling, order entry, electronic mail, and bibliographic retrieval through PaperChase. Beth Israel users can also search the growing clinical database. This retrieval capability, called ClinQuery (Safran et al., 1989), is a powerful tool for answering administrative and research questions. Through this system, hospital practitioners can access the Physicians' Desk Reference (PDR) and receive advice from an attached expert system designed to assist practitioners in treating acid-base problems.
Clinical computing systems at these two hospitals are patient centered and integrated rather than networked or interfaced (i.e., they utilize the central database model displayed in Figure 3-1). These systems also store data for hospitalized and ambulatory patients in a common database within each institution. In addition, the systems handle patient billing functions. Indeed, installation of these clinical computing systems has reduced substantially the length of time between provision of service and receipt of payment for the service. (Accounts receivable dropped by 30 days at Beth Israel when the clinical computing system was installed; when that system