Method of making dual lumen catheters

The method of making a unitary dual lumen catheter having a hub comprising the steps of:

• (a) initially forming a dual lumen catheter having a unitary, elongated flexible tube that is substantially circular in cross-section, the tube having an outer wall member forming a tube having a proximal end and an opposed distal end portion adapted for insertion within the vein of a patient, the outer wall member defining first and second lumens that are separated by an inner common support wall which is substantially circular and joins the outer wall, the first lumen extending longitudinally between the opposed distal and proximal ends of the catheter tube and terminating coextensive the distal end portion of the catheter tube, the second lumen extending longitudinally from the proximal end of the catheter tube and terminating proximal to the distal end portion of the catheter tube, said second lumen further comprising adjacent said distal end a port hole extending through said outer wall member, the first lumen being circular in cross-section and the second lumen being crescent-shaped in cross-section and substantially surrounding the first lumen, the cross-sectional areas of the first and second lumens being approximately equal;
• (b) inserting within the proximal end of the first lumen a first support pin shaped to fit within the first lumen and inserting within the proximal end of the second lumen a second support pin shaped to fit within the second lumen, the pins extending from the proximal end of the tube in a branched configuration;
• (c) placing an extension tube over each of the support pins of the branched configuration, each extension tube being inserted a short distance within the proximal end of the lumen from which the underlying support pin extends;
• (d) placing the dual lumen catheter with the extension tubes and inserted support pins into an insert mold shaped to hold the catheter at the catheter distal end and to hold a softened material around a distal portion of the branched configuration of the extension tubes and pin supports extending from the catheter proximal end;
• (e) placing the softened material in the insert mold around the branched configuration;
• (f) allowing the softened material to harden to form a branched hub integral with the catheter proximal end;
• and
• (g) thereafter removing the support pins from within the catheter and the extension tubes, thereby leaving channels which form the lumens, hub and extension tubes.