Cardiac output monitoring devices are commonly used in ICU patients. The most precise use direct measurement, which require artery cannulation. The gold standard is Swan-Ganz catheter, but it is a very invasive technique. PiCCO (Pulse index Continuous Cardiac Output) is the alternative way of haemodynamic monitoring. This technology is the easy, less invasive and cost-efficient tool for determining the main hemodynamic parameters of critically ill patients. It is based on two physical principles - transpulmonary thermodilution and pulse contour analysis. Both principles allow the calculation of haemodynamic parameters in critically ill patients. PiCCO method requires peripheral artery cannulation.

Cannulation may be followed by artery stenosis.

Aims of the study are:

1. to verify the occurrence of radial artery stenosis after 3 days of having a PiCCO cannula in place.
2. whether 5 days cannulation of radial artery with PiCCO catheter is related to more frequent stenosis rate.

An additional assessment:

1. to check whether the eventual stenosis is still present after 3, 14 and 30 days after decannulation - assessment depending on patients availability

Barbeau test and Doppler - ultrasonography preceded radial artery cannulation. Catheter removal (after 3 or 5 days of cannulation) is followed by Doppler - usg. Usg -Doppler is performed also 3, 14 and 30 days after decannulation - depending on patient being available

Inclusion Criteria:

• critically ill patients with haemodynamic monitoring required

Exclusion Criteria:

• Barbeau test type D in radial artery
• artery inaccessible for cannulation - based on doppler ultrasonography