A drainage tube is a common medical device. A drainage tube can be a single tube or a system of tubes that connect to a cavity or area within the body, to carry fluid out of the body or from one part of the body to another. The drainage fluid varies depending on the function and location of each individual type, including blood, inflammatory fluid, gas, bile, urine, etc.

Patients with urinary retention, benign prostatic hyperplasia or neurogenic bladder disease are common cases that require placement of a bladder drainage catheter in clinical practice. In addition, before certain types of surgery, most commonly cesarean section, patients also need to have their urine drained through a bladder catheter through the urethra.