The AEDMI project, carried out in the Bellvitge University Hospital, near Barcelona, is proposed as an example of clinical decision system prototype development. Several difficulties have been encountered to develop this project. One of them was to find the adequate understanding for the project and proper funding for personnel resources. The support by FIS grants and from the hospital structures was essential to the survival of the project; however the resources always have been below the real needs for development. The difficulties with clinical coding systems, the excessive expectancies upon prototypes, and the lack of culture in information methods were other relevant hinders. The complexity of clinical realm, the uncertainty of medical decisions, and the current trends to substitute the clinical information by data obtained from electronic devices, or analytical monitoring of patients, are additional problems for clinical information managing.