In central venous catheterization, a catheter is inserted into one of the large veins of the neck, upper chest, or groin. This procedure is most often used to give intravenous fluids or drugs when a catheter cannot be inserted into an arm or a leg vein (peripheral intravenous catheter).
Central venous catheterization is occasionally used to monitor central venous pressure (pressure in the superior vena cava, the large vein that returns blood to the heart from the upper part of the body). Central venous pressure reflects the pressure in the right atrium when it is filled with blood. This measurement helps doctors estimate whether the person is dehydrated and how well the heart is functioning. But it has largely been replaced by pulmonary artery catheterization.