An approach to architecting enterprise solutions

Hewlett-Packard Journal, Feb, 1997 by Robert A. Seliger

A frequently mentioned ailment in healthcare information management is the lack of compatibility among information systems. To address this problem, HP's Medical Products Group has created a high-level model that defines the major architectural elements required for a complete healthcare enterprise information system.

HP's Medical Products Group (MPG) produces medical devices such as patient monitors and ultrasound imaging systems, which obtain physiological data from patients, and clinical information systems, which document, retrieve, and analyze patient data.

In December 1994, MPG directed its architects to define and drive the implementation of an open, standards-based MPG application system architecture that would enable:

* Improved application development productivity

* Faster times to market

* Seamless integration of applications developed by MPG and its partners

* Integration with contemporary and legacy systems in an open standards-based environment

To meet these objectives and to help establish MPG as a leader in healthcare information systems, the Concert architecture was conceived. Concert is a software platform for component-based, enterprise-capable healthcare information systems.

The primary objective of Concert is to enable the decomposition of healthcare applications and systems of applications into sets of interconnectable collaborative components. Each component implements important aspects of a complete healthcare application or system of applications. The components work together to realize fully functional applications and systems of applications.

A component-based approach was pursued to leverage the fundamental precepts of good software engineering: decomposition, abstraction, and modularity. We reasoned that an architecture that facilitated decomposing large complex systems into modular components and abstracted the details of their implementation would contribute to development productivity. The ability to use these components in a variety of applications would expedite time to market.

Carefully specified component interfaces would enable flexible integration of components in a seamless manner. Openly publishing these interfaces would enable components developed by MPG's partners to interoperate with MPG's components. The judicious use of healthcare and computing standards would enable integration with systems based upon other architectures.

Concert was developed by MPG in conjunction with HP Laboratories and the Mayo Clinic, a strategic MPG partner. It serves as the technical cornerstone for MPG's group-wide initiative to provide better enterprise solutions for its customers. Key aspects of the architecture have also been applied by HP Laboratories and the Mayo Clinic to develop a prototype electronic medical record system.

Concert also serves as the foundation for the technical development effort of the Andover Working Group for Open Healthcare Interoperability. This MPG-led healthcare industry initiative was been formed to achieve enterprise-wide multivendor interoperability (see page 89).

Concert currently consists of the following elements:

* A general reference model that organizes the architecture of healthcare enterprise information systems into a key set of architectural ingredients

* A model for software components that can be implemented using CORBA-based[1] or Microsoft[R] OLE-based[2] technologies

* An initial set of Concert components including their interfaces and the policies that govern the patterns of interaction between the components

* An approach for organizing Concert component interfaces to represent component application development, system integration, and system management capabilities

* An initial information model that provides an object-oriented description of healthcare terms, concepts, entities, and relationships to establish a common clinical basis for Concert components and the applications developed from them.

Concert Components

To facilitate the description of the Concert component model, an example of one of the components that MPG has developed will be used. The component, called an enterprise communicator, is at the heart of the enterprise communication framework (ECF) that MPG is developing in conjunction with other healthcare vendors and providers that form the Andover Working Group.

An enterprise communicator is a software component that facilitates healthcare standards-based data interchange between healthcare systems and applications within a healthcare enterprise. Different types of communicators encapsulate different healthcare standards. The particular communicator that MPG is currently developing encapsulates the Health Level 7 (HL7) 2.2 data interchange standard.(3) Fig. 1 shows a system based on enterprise communicators.

[Figure 1 ILLUSTRATION OMITTED]

HL7 is a widely used healthcare electronic data interchange standard. Its primary contribution is the specification of a set of messages that healthcare systems can exchange to share clinically relevant data. Examples include messages that enable applications to obtain the results of laboratory tests from the applications that have access to this data.