Abstract: A multilumen catheter having a distal portion with a soft tip and reduced cross-section. The multilumen catheter of the present invention includes a flexible, elongated first catheter tube and a flexible, elongated, dual-lumen catheter tube which has a first and second lumens integrally formed and is disposed within the first catheter tube. The cross-section of the dual-lumen catheter tube is smaller than that of the first catheter tube and therefore, an independent, single lumen is defined in the space between the first catheter tube and the dual-lumen catheter tube. The dual-lumen catheter tube extends beyond the distal end of the first catheter tube thereby providing an overall reduced cross-section of the distal portion of the present multilumen catheter. Furthermore, the dual-lumen catheter tube may be formed from a softer material than that of the first cathether tube thereby providing a softer distal portion of the present multilumen catheter.

Abstract: A dual lumen catheter apparatus and method. The apparatus has an elongated catheter body adapted for insertion into a vein or a fluid-containing body cavity of a patient such as the right atrium of a heart. The catheter body has a septum that runs longitudinally through the interior of the catheter body so as to divide the interior of the catheter into a first and a second lumen. The septum is offset from the longitudinal center axis of the catheter so that the cross-sectional area of the two lumens are of different sizes. The first lumen has a cross-sectional size that is relatively large so that a sufficient volumetric flow rate of blood that is to be oxygenated is able to flow by means of gravity drainage through the first lumen whereas the second lumen is smaller but is still sufficiently large so that an essentially equal volumetric flow rate of blood that has been oxygenated can be returned under pressure through the second lumen.