Abstract: A relation is formed between an n-tuple having n components and formed at a first point in time and at least one other n-tuple having n components formed at at least one corresponding later point in time, wherein n is a natural number equal to or greater than 1, and the components comprise at least one derived parameter and/or one read-in data value. If this relationship satisfies a predetermined calibration criterion, a calibration signal is triggered and is displayed, and/or automatically triggers a recalibration of the haemodynamic monitoring device. For example, the pulse contour cardiac output PCCO is derived from the arterial pressure curve as the constituent component of a 1-tuple. As long as this differs from the reference cardiac output CORef by less than a predefined threshold value, for example 101 or 15% of the reference cardiac output, parameter determination continues without initiating a new calibration.