In this paper, we describe an approach to utilize case-based reasoning meth
ods for trend prognoses for the monitoring of the kidney function in an Int
ensive Care Unit (ICU) setting. Since using conventional methods for reason
ing over time does not fit for course predictions with poor medical knowled
ge of typical course patterns, we have developed abstraction methods suitab
le for integration into our case-based reasoning system ICONS. These method
s combine medical experience with prognoses of multiparametric courses. On
the ICU, the monitoring system NIMON provides a daily report based on curre
nt measured and calculated kidney function parameters. Subsequently, we gen
erate course-characteristic trend descriptions of the renal function over t
he course of time. Using case-based reasoning retrieval methods, we search
in the case base for courses similar to the current trend descriptions. Fin
ally, we present the current course together with similar courses as compar
isons and as probable prognoses to the user. We applied case-based reasonin
g methods in a domain which seemed reserved for statistical methods and con
ventional temporal reasoning. (C) 1999 Elsevier Science Ireland Ltd. All ri
ghts reserved.