A catheter is a tube that is inserted into the bladder through the urethra to drain urine. It is made of natural rubber, silicone rubber, or polyvinyl chloride (PVC) and can be inserted into the bladder through the urethra in order to drain urine. After the catheter is inserted into the bladder, a bladder near the head of the catheter secures the catheter to stay in the bladder and is not easily dislodged, and the catheter is connected to a bag to collect the urine.

What are the conditions that require a catheter?
1. Acute or chronic urinary retention or bladder neck obstruction.
2. Refractory urinary incontinence
3. Inability to control urination independently
4. Prolonged bed rest
5. Perioperative surgery
6. Need to accurately detect the amount of urine
7. Others: bladder instillation drug therapy, aseptic urine specimen retention