The technique of blood samples extraction from the radial artery through an arterial catheter with a 3-way stopcock and automated washing with valve of fast flow is better than the one carried out through a fixed reusable arterial blood sample syringe and its manual washing because it shows a minor incidence of the complications originated from technical manipulation as infection, pseudo-aneurysm, ischemia or thrombosis of radial artery or obstruction of the catheter.