The authors deal with non-invasive haemodynamic monitoring system NICO. This device uses the gas analysis and the Fick principle to compute cardiac output (CO). It based on the changes of CO2 elimination and end-tidal CO2. The shunt blood which does not participate in CO2 elimination is calculated from the values of SaO2 and FIO2 with the use of Nunn’s diagrams. The NICO device can be easily used both in the intensive care unit and the operating room. The authors present a few cases to demonstrate the use of NICO system which shows not only haemodynamic parameters but also some respiratory system parameters.

        Key words: cardiac output – Fick principle – CO2 elimination