Klinische Projekte

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FuzzyKBWean: Knowledge-Based Weaning from Artificial Ventilation

Ch. Schuh1, W. Koller1, M. Kolb2, Ch. Zelenka2, M. Hiesmayr2, K.-P. Adlassnig1

1 Department of Medical Computer Sciences, Section on Medical Expert and Knowledge-Based Systems, University of Vienna Medical School, Spitalgasse 23, A-1090 Vienna, Austria
e-mail: klaus-peter.adlassnig@meduniwien.ac.at
2 Department of Cardiothoracic Anaesthesia and Intensive Care Medicine, University of Vienna Medical School, Währinger Gürtel 18-20, A-1090 Vienna, Austria

FuzzyKBWean is an open-loop fuzzy control system for optimization of the ventilation and weaning process of patients after cardiac surgery at one of the ICUs of the Vienna General Hospital. The system is directly connected to the PDMS of the ICU and runs on the bed-side computers, as is described in [1]. In one-minute intervals, it actively accesses the PDMS data base and transfers the patient's medical data necessary for ventilation and weaning decisions.

According to the well-known structure of fuzzy control systems, a fuzzification step is followed by the fuzzy rule evaluation. The fuzzy rules in FuzzyKBWean contain linguistically expressed physiological parameters of the patient and actual ventilator settings in their antecedents, yet crisp proposals for new settings of the ventilator in the consequences of the rules. The application of the Sugeno control method to combine rule output of the same kind is thus possible [2]. Moreover, a fuzzy set and fuzzy rule editor, called FuzzyKBWEdit, has been programmed that allows the cooperating physicians in the position to carry out knowledge base changes directly at the ICU ward without assistance of a knowledge engineer.

An early study of FuzzyKBWean was published in [3]. A recent clinical trial showed that a number of appropriate proposals for ventilator settings are given at stages of the weaning process, earlier than the attending personal would react. Thus the proposed adjustments to stabilize the ventilated patient are more timely and allow a reduction in ventilation duration. Decisions to start the weaning process and finally to extubate the patient are supported by the implemented rules still considering observations of the clinical context. They may yield to less suffering by the patient and a lower cost.

References

  1. Schuh, Ch., Hiesmayr, M., Adlassnig, K.-P., Zelenka, Ch., Klement, E.P. (1998) Integration of Crisp- and Fuzzy-Controlled Weaning in an ICU PDMS. In: Proceedings of the World Automation Congress, WAC '98, TSI Press, Albuquerque, 299–304.
  2. Schuh, Ch. (1998) Wissensbasierte Entwöhnung vom Respirator unter Verwendung von Fuzzy- und Nichtfuzzy-Regelungsmodellen. Dissertation, Technical University of Vienna, Vienna.
  3. Hiesmayr, M., Gamper, J., Neugebauer, T., Mares, P., Adlassnig, K.-P., Haider, W. (1993) Clinical Application of Patient Data Management Systems (PDMS): Computer-Assisted Weaning from Artificial Ventilation (KBWEAN). In: Lenz, K., Metnitz, P.G.H., eds., Patient Data Management in Intensive Care. Springer-Verlag, Wien, 129–138.