The bladder holds urine until it can be expelled from the body through urination. Once the kidneys create the urine, it travels through the tubes called ureters into the bladder. A bladder catheter, often called a urinary catheter, is a tube inserted into the bladder to drain the urine from the body instead of normal urination. A bag attached to the catheter tube collects the urine.

A catheter may be needed for a variety or reasons. In individuals who have trouble urinating, either temporally or long-term, a bladder catheter may be needed. Catheters are also inserted when the volume of urine needs to be measured or collected and tested for diagnostic purposes. Catheters are also often used during surgery to monitor urine flow.

Urinary catheters can be used for a very short time, during procedures, such as surgery or while recovering from an injury or illness. Long-term bladder catheters may also be needed for individuals with problems such as spinal cord injuries. These types of catheters are called long-term indwelling catheters.

The procedure to place a bladder catheter is called catheterization. The urine comes out of the bladder and flows through the urethra to leave the body. Prior to the catheterization, the urethra is cleaned and a sterile bladder catheter is inserted into the bladder through the urethra. A small balloon is attached to the end of the catheter to hold it in place. A small amount of sterile water will be inserted into the port to inflate the balloon once it's in the bladder.

Inserting a bladder catheter is usually a quick procedure. Although it's usually not painful, a patient may feel some discomfort. The length of time the catheter stays in the bladder depends on the initial reason it was placed and patient condition. Removal of the catheter involves deflating the balloon and slowly pulling the tube out of the bladder through the urethra.

Complications during placement of the bladder catheter or shortly after are uncommon, but can occur. Bleeding or trauma to the urethra can occur, especially if the balloon is inflated before it is threaded completely through the urethra. The catheters can also become blocked, which obstructs the flow of urine from the body.