Patient monitoring in intensive care units (ICUs) is a difficult task. This is due, in part, to the important role that the dynamic and static contexts play in the interpretation of the measurements. Classical approaches dealing with this problem usually consist of: (a) building systems for massive acquisition of data and display of the information, and (b) building expert systems. In the first approach the data are not interpreted. In the second approach the use of heuristic techniques is useful to obtain conclusions based on the analysis of the information already available. These conclusions, however, do not take into account the particular characteristics of the patient under consideration. In other words, these systems do not include “common sense” either for interpreting measurements or to prescribe therapies. In this paper we explain the nature of a different procedure, in which a patient-oriented symbolic approach is followed in order to define some particular circumstances that may modify the criteria for the interpretation of the corresponding variables. These interpretations are adapted to the particular case under consideration. The approach is illustrated with an application in acute ventilatory management.