Within the daily workload at a ward there is a considerable amount of information processing. It is the task of a systematic management of hospital information systems to provide health professionals with the right information in the right place at the right time. This paper deals with the consequences for the management of hospital information systems if health professional workstations are introduced as a means for this information logistic and with the experiences gained in the Heidelberg University Hospital. Health professional workstations are formally defined in the context of a three level graph-based model of hospital information systems. It is found that health professional workstations have communication needs not only on the physical level of computer systems in the hospital information system but also on the logical tool level, which is the level of application systems. On this level communication servers or brokers are of considerable importance. In Heidelberg there are about 200 health professional workstations (MEDIAS) in routine use.