Monitoring the fuzziness of human vital parameters

In critical care, patients are surrounded by a multitude of devices for monitoring, diagnostics, and therapy. These devices include patient monitors to measure and monitor human vital parameters, therapeutic devices to support or replace impaired or failing organs and also to administer medications and fluids for the patients. In this special environment the complexity of biological systems makes traditional quantitative approaches of analysis inappropriate. There is an unavoidable substantial degree of fuzziness in the description of the behavior of biological systems as well as their characteristics. Fuzzy logic provides a suitable basis for the ability to summarize and extract from masses of data impinging upon the human brain those facts that are related to the performance of the task at hand. Therefore, this approach may be very suitable for intensive care medicine, where experience and intuition play an important role in decision-making. This paper surveys the utilisation of the fuzzy set theory in medical sciences in general, as well as on the basis of two concrete medical fuzzy applications.