Some technical details on Watson
ibm.com
ibm.com
Here is a recent study comparing quality of care using EHR/CDSS and without: http://archinte.ama-assn.org/cgi/content/abstract/archintern...
"Our findings indicate no consistent association between EHRs and CDS and better quality. These results raise concerns about the ability of health information technology to fundamentally alter outpatient care quality."
I doubt any core changes would have been need to Lucene for this application.