We developed a knowledge-based system, VIE-VENT, for monitoring and therapy planning of the artificial ventilation of newborn infants. Clinical and textbook knowledge were implemented in VIE-VENT’s knowledge base. Therapy planning was based on transcutaneously and invasively determined blood gas measurements and on clinical observations. After the selection of appropriate input parameters, measured data were validated and transformed into qualitative values. If these values differed from target values, therapeutic actions were proposed according to heuristic clinical rules of artificial ventilation. VIE-VENT was specifically designed for practical use under real-time constraints in Neonatal Intensive Care Units (NICUs). VIE-VENT was applied to the ICU data set provided by the organizers of the AAAI-AIM-94 symposium and a neonatal data set, which covered a neonatal case of similar severity. It included all transcutaneous measurements and allowed to explore the full potential of VIE-VENT.