Based on the hypothesis that the strategy of using Closed-Blood Sampling Devices (CSBD, experimental group) compared to the usual practice (waste discard volume, control group), in critically ill adult patients, will decrease the amount of blood withdrawn for laboratory tests, we want to analyze the number of red blood cells (RBC) administered and arterial catheter-related adverse events (catheter-related bacteremia, catheter obstruction, CBSD malfunction, loss of arterial pressure waveform on the patient's bedside monitor) in both study groups, during ICU stay and up to a maximum of 21 days.