Abstract: A dual lumen cannula for use in haemodialysis has an improved leading end to facilitate insertion and an improved coupling for connection to blood extraction and return tubes. The improved leading end has a conical tip centered on the longitudinal axis of the cannula and, in the leading end, the extraction lumen is blanked off by using an insert to prevent blood flow downstream of the extraction lumen, and to minimize blood stagnation and damage. The improved coupling is generally Y-shaped and the extraction and return lumens of the cannula terminate in conical shaped ends which receive extraction and return tubes with similar shaped ends. The ends of the extraction and return tubes have minimal thickness so that when inserted the interior surfaces of the cannula lumens and the tubes merge smoothly to minimize blood impact problems. Methods of manufacturing the tip and a Y-shaped connecting piece for connecting the dual lumen cannula to tubing are also described.

Abstract: A dual lumen cannula particularly for use in haemodialysis by inserting the cannula into the subclavian or femoral vein of a patient to contemporaneously remove blood from the vein for treatment and to return treated blood to the vein downstream from the point of removal. The cannula includes a pair of lumens separated by a septum. Blood is withdrawn through one of the lumens and treated blood is returned through the other lumen. The cannula is formed from a flexible thermo-plastic material and is sufficiently flexible to permit bending to conform to the shape of the vein without damage or kinking. The cannula has a peripheral generally cylindrical wall with a septum extending between spaced locations on the interior surface of the wall to define a pair of discrete lumens and at least one of the lumens is deformed at its end to facilitate insertion.