Sidebar: Taking the Pain Out of Integration

Computerworld - Ohio State University Medical Center's SOA-based patient-tracking system had its origins in frustration. Many hospital software and patient-monitoring equipment products that the center was using were unable to connect to patient databases.

This connectivity is necessary for patient tracking and for adding new data to the overall electronic medical record, which draws from a variety of databases, says Furrukh Khan, director of the Collaborative for Applied Software Technology at the medical center.

"The software supplied by vendors either doesn't extract data from existing databases, or it's bound together with proprietary interfaces," says Khan. Before Web services, "you had to either write the back-end part of this type of application yourself, or write it specifically to one type of software. Now the monitoring software sends requests to the SOA in XML, and we've built in a system that includes the rules of the hospital."

With Web services, Khan says, an organization is no longer forced to settle for simple asynchronous point-to-point interfaces between applications using HL7, the industry-standard protocol for hospital data transactions.

After merging two of its member hospitals, CareGroup Healthcare System found that it might have patient records for, say, a Joe Smith on more than one hospital campus. The patient medical record systems had to be linked in order to avoid errors in patient demographic data.

Using Microsoft's .Net Framework, IT staffers developed the Record Locator Service, which automatically locates the data. The Web service enables the user to provide name, gender and date of birth to a "community utility" Web service that returns a list of all care sites that a patient has visited.

"We created a Web service that figures out where all the patient records live and, in turn, who the patients are, assuming you've wrapped all the legacy systems in Web services. It basically says 'Go fetch' across the entire institution," says John Halamka, CIO at CareGroup. "The beauty is creating an abstraction layer to divorce you from the complexity of the underlying application. You don't even have to know what the application is."

Halamka's IT staff has also developed Web services that use SOAP for a number of HL7 systems, including those that provide medication lists and problem lists, as well as "wrappers" for older laboratory, radiology and other departmental systems.

"These services are all objects that let me not only link data from different systems," says Halamka, "but also do audits and security without having to build one-off solutions for each vendor's system."

RECORD LOCATOR SERVICE HERE'S HOW RLS WORKS 1. After a patient visit, health care provider publishes index of records location to RLS registry. 2. Patient sees another health care provider, which queries RLS for the location of other records for the patient. 3. RLS provides index to record location. 4. With the index, second provider requests record from original provider. 5. Original provider sends records. The last two steps are not RLS functions. Source: Computer Sciences Corp.