Adam Wright


May 2007

Document Type


Degree Name



Dept. of Medical Informatics and Clinical Epidemiology


Oregon Health & Science University


Myriad studies have shown that clinical decision support can reduce medical errors and improve healthcare quality in both inpatient and ambulatory settings. However, only a small number of sites (generally academic medical centers and large integrated delivery networks) make significant use of the most advanced and effective decision support interventions. Community hospitals and independent healthcare providers generally make only limited use of decision support, in fact frequently opting to disable it entirely in their clinical systems. This lack of use stems from a variety of causes, ranging from technical to political to economic; however, perhaps the main cause is resources: academic medical centers and integrated delivery networks are more likely to have clinical decision support committees and in-house development resources. The natural solution to closing this gap seems to be content sharing - having the successful sites share their content with the rest of the hospitals and providers. In fact, medical informatics has worked on a variety of approaches for sharing content, starting with Arden Syntax in 1989. However, to this day, none of these content sharing systems have seen significant adoption and many have never made it out of the lab. In this dissertation, I introduce a new approach to sharing decision support content which leverages existing work towards developing a National Health Information Network (NHIN). I call this approach SANDS: a Service-oriented Architecture for NHIN Decision Support. Most approaches for sharing decision support content involve developing a lingua franca for encoding clinical knowledge. However, because clinical knowledge is diverse and complex, and not always easy to represent in the form of if-then rules, such approaches necessarily constrain the scope and type of clinical knowledge which can be represented. SANDS, by contrast, defines a set of interfaces that a decision support service should make available, but leaves the choice of knowledge representation up to the implementer. In addition to this interface-oriented design, SANDS allows knowledge to be distributed. With SANDS, instead of storing all knowledge in the electronic health record, it is made available over a network which many can contribute to. For example, a medical specialty society might release its guidelines over SANDS, while AHRQ would release evidence reports, and a commercial vendor might provide (for a fee) access to its drug information database. This frees each care provider from having to manage and maintain a complete body of decision support content - the medical equivalent of re-inventing the wheel. The basis for SANDS is a functional taxonomy of clinical decision support, developed through analyzing the decision support content of a large integrated delivery network. From this framework, I developed a complete technical architecture and service definition. In turn, I built a prototype of the architecture. This prototype integrates a prototype NHIN with a variety of decision support systems, ranging from drug interaction checking to diagnostic decision support. The prototype provided a test-bed to study the utility, performance and relative advantages of the SANDS architecture. Ultimately, SANDS proved to be useful and effective, with good performance and significant technical and functional advantages over earlier approaches.




School of Medicine



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