Softening Catheter.

摘要

A tubular cannula (12) has distal and proximal end portions (14,16), and a transition section (20) connecting the distal and proximal end portions. A passageway(18) extending through the cannula. The proximal end portion has larger inner and outer diameters and has thicker walls than does the distal end portion. The diameter and thickness differences are progressive and gradual and accommodated in the transition section. The cannula is constructed of a material that softens on being inserted into a living body and/or contacted with an aqueous medium. The cannula combines kink resistance external of the living body with the advantages of a softening and generally swellable catheter.