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and electron beam CT angiography images; admission,
discharge, and transfer data; and pharmacy orders. All of
this data must be stored securely and reliably (and eventually archived intelligently) while remaining accessible
on demand. In addition, the data must be easily searched,
transmitted, and organized by a wide variety of employees
spread across multiple locations. Add the need to easily and
quickly input and update information, and you’re looking
at a complex piece of IT infrastructure.
The UCLA Health System met those demands with its
atient-oriented documentation system (PODS), an electronic medical records (EMR) repository that provides
storage and retrieval capabilities for more than 20 million
documents. In the bigger picture, PODS is a critical source
of patient information for the UCLA document management system extended SOA (xSOA). Along with PODS, the
xSOA provides viewer interfaces to a GE BDM pharmacy
information system, a CliniComp Essentris acute care
system, an Orion Soprano clinical data system, and a forms
portal. The xSOA Central Document Bus connects to a GE
picture archiving and communication system (PACS), clinical applications and images, and the PODS repository. The
Image Bus provides access to patient diagnostic images,
whereas a Forms Bus handles the large variety of electronic
forms used by UCLA Health Services. An HL7 Message Bus
provides HL7-compliant communications.
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Combining an SOA with DB2 databases, PODS provides
,000 doctors and 3,000 nurses with access to patient
records. The system supports more than 400 electronic
forms for data entry; these forms replace the 1,000 paper
forms used previously, helping to eliminate errors due to
handwriting misinterpretation or blank fields. The database holds information for about 2 million patients and
grows by 12,000 documents per day as new test results,
doctor’s notes, and other patient-related data are added.
PODS includes a document repository and metadata
epository, pairing medical record files with a DB2 database. PODS stores medical record image files on file servers;
it uses an IBM DB2 database to store corresponding metadata and a network attached storage array for the image
files, including PDFs and text.
When a document enters the system, it is stored in the
le server and indexed in the DB2 database. Documents are
not deleted because the PODS repository also serves as an
archive of patient data. To ensure survivability and high
availability for 24x7 operations, the PODS architecture
includes redundant servers and databases, with data replication to synchronize between database servers.
The DB2 database metadata store currently contains
0 million rows of information. The metadata is stored as
XML, using the DB2 9 native XML engine. According to Dr.
Charles Wang, architect manager at UCLA Medical Center
Computing Services, the more than 400 schemas used for
PODS comply with the W3C XML Schema language. The
PODS software maps those different schemas into a single,
virtual schema for the entire system. The system uses a
four-key composition to create a unique identifier for a
document paired with its metadata.
To safeguard patient privacy, the PODS design uses a
multilevel security model. Besides built-in DB2 security capabilities, the software architecture includes a document and
metadata handler that is integrated with a security service.
It also features role-based security and a single sign-on capability. Security, concurrency control, parallel processing, and
versioning are but a few of the advantages of using DB2 for
storage of XML schemas and documents, as opposed to
dealing with those problems on an ad hoc basis when using a
file system to manage XML documents and schemas.
UCLA Health System builds on SOA
The PODS implementation is a good example of how an SOA
enables disparate applications to use essential services—
in this case, services for accessing patient information.
Documents enter the system via a document service interface and are placed in queues. The PODS architecture
