An arterially measured pressure signal is continuously read in and temporarily stored in the working memory (RAM). The function p(t) is processed by the central processing unit (CPU), to calculate the heart/time volume PCCO and other hemodynamic parameters. The calculation comprises the following steps: The systemic vascular resistance SVRk is calculated for the current pulse period. The stroke volume SVk is numerically determined from the pressure values of a pulse period, according to the following equation: