A method and apparatus for retaining a catheter tip in a fixed position within a blood flow and preventing it from contacting a blood vessel wall. The apparatus includes a tip retainer at the distal end of the catheter that anchors the tip of the catheter within the blood vessel. The catheter tip is...http://www.google.com.au/patents/US5509900?utm_source=gb-gplus-sharePatent US5509900 - Apparatus and method for retaining a catheter in a blood vessel in a fixed position
