Clinical Guidelines are a major tool for improving the quality of medical care. A major current research direction is automating the application of guidelines at the point of care. To support that automation, several requirements must be fulfilled, such as specification in a machine-interpretable format, and connection to an electronic patent record. We propose an innovative approach to guideline application, which capitalizes on our Digital electronic Guidelines Library (DeGeL). The DeGeL framework includes a new hybrid model for incremental specification of free-text guidelines, using several intermediate representations. The new approach was implemented, in the case of the Asbru guideline ontology, as the Spock system. Spock's hybrid application engine supports the application of guidelines represented at an intermediate format. Spock uses the IDAN mediator for answering complex queries referred to heterogeneous clinical data repositories. Spock was evaluated in a preliminary fashion by applying several guidelines to sample patient data.