In medicine a<unk>  is a tube that can be inserted into a body cavity, duct or vessel.<unk> s thereby allow drainage or injection of fluids or access by surgical instruments. The process of inserting a<unk>  is<unk> isation.   In most uses a<unk>  is a thin, flexible tube: a "soft"<unk> ; in some uses, it is a larger, solid tube:  a "hard"<unk> .
Catheter
Balloon catheter
Arterial line
Fluid
Machine perfusion
Colloid milium
Central venous catheter
Ventricular assist device