Vol. 10 •Issue 9 • Page 65
Legacy Systems SaviorsDoD employs modern technologies to transform the legacy Composite Healthcare System into AHLTA.By Robert E. Connors and Col. David GilbertsonUsing advanced technologies, the Department of Defense (DoD) has modernized its venerable Composite Healthcare System (CHCS) to support the transition to a new enterprise-wide electronic health record (EHR) known as AHLTA.DoD has deployed AHLTA to 118 of 138 planned Military Treatment Facilities. DoD employs BEA Tuxedo, Sun (SeeBeyond) eGate, ESI and M/Objects, and Proxicom Daou Systems Enosus to synchronize applications and data in the 104 CHCS legacy host sites with the AHLTA clinical data repository (CDR), using HL7 messaging. Synchronization is accomplished in a manner that provides semantic interoperability, and ensures continuous high availability and reliability. DoD undertook a significant mapping effort to ensure that the many different medical terms in the 104 CHCS host sites are completely computer-processable in the AHLTA CDR, and that this data is maintained in near real time.DoD plans to wrap the CHCS Massachusetts General Hospital Utility Multi-Programming System (MUMPS) code in InterSystems Caché, which combines objects and SQL, eliminates object-relational mapping, and enables rapid Web application development, excellent transaction processing speed, scalability and real-time queries against the transaction database.
AHLTA is being deployed in a phased approach, using blocks of functionality. When complete, AHLTA will provide a comprehensive longitudinal health record for 9.2 million DoD beneficiaries it will directly support DoD Access to Care, Population Health and Force Health Protection objectives.
History
In the late 1980s, the Military Health System deployed a MUMPS-based computerized physician order entry (CPOE) results retrieval system for pharmacy, laboratory and radiology. CHCS also provided outpatient registration, appointing, and scheduling functions; admission, disposition and transfer functions; inpatient documentation and drug alerts. Today it documents 50 million appointments and performs 70 million prescription transactions annually. It shares secure data with workload accounting systems, commercial reference laboratories and Veterans Health Administration (VHA) facilities.
CHCS is hosted at 104 treatment sites and is fully deployed to almost 500 facilities. It employs 73,000 workstations and laptops, along with 16,000 printers, and is used by tens of thousands of personnel 24/7/365. It is reliable, available and quick, and remains one of the world’s largest health information systems. For 15 years, CHCS has reduced patient wait time and increased beneficiary access to health care. Despite these advantages, however, CHCS by itself cannot provide for complete outpatient or inpatient documentation to support a life-long patient EHR. CHCS supports functions only at a single host site, maintaining information for patient-provider encounters that have occurred at that site.
Building upon legacy system
DoD began designing the CHCS replacement in 1996. Called CHCS II, and recently renamed AHLTA, the EHR builds on the CHCS CPOE system and provides all documented medical exams, ancillary services, episodes of care, changes in health status, and pre- and post-deployment information in a single, central CDR. Regardless of where medical care is rendered in the world, the patient’s medical evaluation and care will be available in AHLTA to support collaborative care.
Challenges
When the 104 CHCS sites were initially established, there were no standards established for medical terminology, and no controlled medical vocabulary (CMV). For example, the following constructs were present in the 104 CHCS host sites. AHLTA was built to place this data in the correct context for providers:
Semantic interoperability
COLD (NCID 68215): A sensory perception, “I’m feeling cold”
COLD (NCID 1005480): A pulmonary diagnosis, Chronic Obstructive Lung Disease
COLD (NCID 1005313): An upper respiratory viral infection, “I have a cold.”SynonymsNCID 10078663 could be depicted as: Acute Sinusitis
ACUTE SINUSITIS
Acute sinusitis, NOS
Sinusitis, acute
Acute infection of nasal sinusitis, NOS
Acute inflammation of nasal sinus, NOS
C0149512 (UMLS)
D2-01110 (SNOMED)
Establishing the CDR was the key to providing semantic interoperability, where information exchange was completely computer-processed. While standard HL7 2.4 messaging can handle the conversion of various files from one structural format to another, more sophisticated techniques are required to ensure that terms mapped from one system mean the same in the other system. The CDR and CMV, provided by the 3M Care Innovations Suite, include the 3M Health Data Dictionary (HDD), which works in conjunction with the MEDCIN terminology engine to provide semantic interoperability. AHLTA automates evaluation and management coding for injuries, conditions and diseases, using ICD-9 and CPT-4 codes.DoD believed in the concept of the CDR early in the AHLTA program. DoD leaders understood that a CDR had to permanently store data from many sources, be able to handle data in many formats (images, text, XML), and enable finely structured, explicitly coded data to support bio-surveillance efforts and cross-patient analysis of data for patient safety, quality and research purposes.DoD populated the CDR initially with 25 months of historical normalized lab, pharmacy and radiology data for each patient, which was transmitted from each CHCS host site. This data is now synchronized with the CDR in near real time through distributed transaction processing technologies and interface engines such as Sun (SeeBeyond) eGate, BEA Tuxedo, and development methodologies employing M/Objects, ESI Objects and Proxicom Daou Systems Enosus. These technologies are further described later in this article.In the near future, a Terminology Service Bureau will add SNOMED coding and Problem Knowledge Coupler, Inc., terms to further enhance semantic interoperability. The ultimate goal is to create a CDR and CMV that are compliant with the HL7 3.0 Reference Information Model.
Fiscal and technical constraintsAHLTA is being built using incremental development and delivery of blocks of functionality based on service operational priorities, and funding available through the Program Objective Memorandum budget process.Because of the size of this project, a phased approach was required, as all funding was not available immediately. The 1996 decision to interface CHCS with AHLTA was also supported by the unavailability of a commercial off-the-shelf EHR technology that could support the military’s functional capabilities, scalability requirements and three-tiered technical architecture. In addition, DoD knew that the CDR was the foundation for providing all of the components of a true EHR: clinical documentation and display, workflow and decision support. By leveraging the proven existing CHCS CPOE system, and interfacing it with a new commercial CDR, DoD was able to move out quickly in establishing an EHR to meet its primary objectives.Blocks 1, 2 and subsequent releasesAHLTA Block 1 deployment is nearly complete and will support 63,000 users. Clinicians enter outpatient clinical encounter documentation via clinical workstation at the point of care, using a common presentation layer across the enterprise.This human-computer interface is engineered using Visual Basic, and is based on the Microsoft Style Guide. The interface looks similar to Microsoft Outlook, providing clinicians with a picture of scheduled patients for their work day and actions required. Clinicians can prepare an electronic “SOAP note” using the MEDCIN terminology engine. Block 1 also provides automated clinical practice guidelines, and a complete set of alerts for medical complications and preventive health care promotion.
Block 2 will add 6,371 users, and will provide optical order entry for the production of military spectacles at military fabrication laboratories, and an electronic dental charting application.
Subsequent releases may add up to 21,575 users, provide inpatient and emergency services, and expand laboratory, pharmacy and radiology capabilities.
AHLTA technical architecture
System interface devices and local and wide area networks (LANs/WANs) connect system components in a manner that supports heterogeneous distributed hardware platforms and operating systems. Local Cache Servers (LCSs) provide for continuity of operations should the connections to the central CDR be lost. The system is engineered to have 99.5 percent end-to-end availability.
The Primary Computing Facility is located at a secure government location and includes:
Clinical Data Repository (CDR) Server Subsystem. Hosts the 3M Care Innovation Suite (CIS) in a highly clustered configuration with an Oracle 9i Database.
CDR Storage Array Subsystem. Highly available, high-speed, high-capacity disk array.
Interface Engine (IE)/Interface Engine Front End Processor (IE FEP) Disk Storage Array Subsystem. A messaging system that supports the movement of CHCS and other system data to the CDR; translates HL7 messages broadcast by CHCS into a format that follows the 3M database schema.
IE Front End Processors (FEP) Subsystem. Provides connection management to the database so that scarce connection resources can be shared; 3M CIS is designed to use BEA Tuxedo Server as the connection manager to the database.
AHLTA Client Workstation (WS) Front End Processor (Tuxedo) Subsystem. Manages AHLTA user connections for CDR Server Subsystem connections
Computerized Immunization Tracking Application (CITA) Server Subsystem. Interchanges immunization data with the Defense Enrollment Eligibility Reporting System (DEERS).
Enterprise Security Server Subsystem. Provides and enforces single-sign-on and role-based access control and hosts SecureD SnareWorks security software.
Tuxedo Transaction Manager (TM) Server Subsystem. Provides load balancing or connections managed between Front End Processor User Connection Managers in a clustered fail-over solution.The Military Treatment Facility (MTF) Host Site includes:
Local Cache Server (LCS). Provides a local data store and connection to front-end user functionality as well as mapping and synchronization of data from CHCS to the AHLTA CDR.
End User Device Subsystem. PC-based connection to front-end user functionality; considered a heavy client in that it hosts the MEDCIN terminology engine and some Tuxedo end-user components, as well as a semi-customizable clinical display and dashboard
AHLTA integration technologies
DoD employed the following “legacy system savior” technologies to leverage its investment in CHCS, and transform it into AHLTA, one of the world’s leading electronic health records:
Sun (SeeBeyond) eGate Integrator. Provides a J2EE-compliant and Web services-based distributed integration platform for application connectivity, data transformation, guaranteed transactions, and message translation, mapping, storing and routing.
BEA Tuxedo. Middleware for high-performance distributed transaction processing, which helps unlock enterprise legacy applications and extends them to a services-oriented architecture, while delivering unlimited scalability and standards-based interoperability.
InterSystems Caché. In 1994 InterSystems bought various MUMPS versions and in 1997 released Caché, using the MUMPS storage engine and language, but with object-oriented services on top.
ESI Objects (Easy CHCS), M/Objects, and Common Business Objects. Objects are self-contained modules of data and associated processing. Most programmers today use a relational database for data storage, and Microsoft has created classes that mediate between the object-oriented viewpoint of the C+ language and VB 2005 programming on the one hand, and the tables/rows/columns perspective of relational databases on the other (ADO.NET). ESI Technology Corp. and Proxicom, Inc. have developed objects for the CHCS outpatient modules. Programmers can also create objects in Caché and then use their wizard to import Caché objects into proxy C# classes. Those custom codes use standard filenames that provide a read/write request without violating CHCS business rules.
Proxicom Daou Systems Enosus Integration Engine. Allows fast, unrestricted access to any M-based database from almost any mainstream application within a standard operating network. This provides a methodology to call directly into the CHCS M/MUMPS system data and rules from Oracle, Visual Basic and Java.
Capacity planning. Given the significant load that is being placed on CHCS and AHLTA components, DoD used various resources in planning the capacity of the system, and in performing load testing. Test environments were established in Cupertino, Calif., where Hewlett-Packard, Northrop Grumman, SAIC, Sun, Oracle, 3M, and government engineers simulated various loads on hardware and software configurations.Currently end-to-end business availability and performance is monitored continuously using Mercury Topaz, Tivoli TAPM and custom software.
When complete, AHLTA will provide a comprehensive longitudinal health record for 9.2 million DoD beneficiaries, and directly support DoD Access to Care, Population Health and Force Health Protection objectives. By using the technologies mentioned, the DoD has been able to leverage its existing investment in CHCS and the data it retains.
Mr. Connors, FACHE, PMP, is CEO of E-Health Designs, LLC, www.ehealthdesigns.com, and was a senior consultant in the DoD TRICARE Clinical IT program office. He has 26 years of line and staff management experience in the Military Health System, with a focus on implementing value-added health care information technology solutions. Mr. Connors is currently evaluating speech recognition and natural language processing technologies for AHLTA at the Army’s Telemedicine and Advanced Technology Center, Fort Detrick, Md.
Col. David Gilbertson is the program manager for the DoD TRICARE Clinical IT program office. He has additional training in information systems management, project management and acquisition management. Col. Gilbertson has more than 23 years of health IT experience including three CIO assignments and a teaching position at the Army’s Academy of Health Sciences.
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