A vascular access treatment is inserting a flexible and sterile thin plastic tube, or catheter, into a blood artery to give an efficient means of collecting blood or delivering drugs, blood products, or nutrients into a patient's bloodstream over weeks, months, or even years.During a vascular access operation, the catheter is placed through the skin and into a vein (usually in the neck, arms, or legs), and the tip of the catheter is positioned in a major central vein that empties near the heart.