Different minimally invasive haemodynamic monitoring techniques are commercially available today and in the recent years they have proved adequate in replacing the pulmonary artery catheter under certain clinical conditions.Moreover, several of these techniques provide additional new parameters primarily related to preload assessment.Therefore, in order to be used in daily clinical practice, the diversity of minimally invasive haemodynamic monitoring requires knowledge of the different techniques, the different parameters provided by the devices and their clinical validity. The aim of the present article is to review the most widely used minimally invasive cardiac output monitoring techniques; emphasize the new parameters available for preload assessment;and propose a modular stepwise monitoring concept.