Urinary catheters are flexible tubes placed in the bladder to drain urine. Catheters may be placed through the urethra or directly through the skin of the lower abdomen.
The most common reason for urinary catheterization is to monitor the output of urine. This may be needed during surgery or a hospital stay for severe illness. For the long term, it is better to have people catheterize themselves when needed, if possible, rather than leaving a catheter in place. Short-term urinary catheterization has few risks or side effects.
Catheters that are placed through the urethra have a smooth tapered tip and two outlet ports. The larger port drains the urine, and the other is for inflating the balloon that keeps the catheter from slipping out. Catheters are made of several materials, which vary in slipperiness. Some catheters have the tip curved upward, for use in men with large prostates. Other catheters have an extra hole so they can be placed over a wire to guide placement in the bladder.
The genital area is first cleansed with a sterile solution. The catheter is then lubricated and passed gently through the urethra into the bladder. Its proper placement is indicated when urine is returned to the catheter. The balloon is inflated with a small amount of fluid. The catheter is then taped or strapped into place. When the person is in bed, a large bag is used to collect the urine. If a person is walking around, bags that are smaller and easier to use are strapped to the leg.
Sometimes it is more advisable to place a catheter directly through the skin of the lower abdomen into the bladder rather than go through the urethra. This might be done when the urethra is damaged, infected, or blocked by cancer. The catheter is placed with a needle and wire through the skin, or a very small incision over the bladder is made. This might be performed under local, regional, or general anesthesia.
The catheter is held in place with a balloon or by the shape of the catheter. The catheter is often sewn into place on the skin, as well. This kind of tube through the lower abdomen is more commonly used when people need long-term catheterization and cannot catheterize themselves when necessary.