An indwelling catheter is a flexible tube that stays inside your bladder to drain urine continuously into a collection bag. Unlike a catheter that’s inserted and removed each time you need to empty your bladder, an indwelling catheter remains in place for days, weeks, or sometimes months. A small balloon inflated with sterile water near the tip holds it securely inside the bladder so it doesn’t slip out.
How an Indwelling Catheter Works
The catheter is a thin, flexible tube made of silicone, latex, or vinyl. One end sits inside the bladder, and the other end connects to a drainage bag outside the body. Once inserted, about 5 mL of sterile water is injected through a separate channel in the tube, inflating a small balloon at the tip. That balloon rests against the base of the bladder, keeping the catheter anchored in place. Urine flows through the tube by gravity into the collection bag, so the bladder never fills up the way it normally would.
There are two ways an indwelling catheter can be placed. The most common is through the urethra, the natural opening where urine exits the body. This type is often called a Foley catheter. The second option is a suprapubic catheter, which enters the bladder through a small surgical opening in the lower abdomen. Suprapubic catheters are typically placed in a hospital or clinic and may be preferred when the urethra is injured, blocked, or when long-term catheterization is needed.
Why Someone Might Need One
Indwelling catheters are used when a person can’t empty their bladder on their own or when precise urine measurement is medically necessary. Common reasons include urinary retention (where the bladder won’t empty completely), recovery from certain surgeries, severe incontinence that can’t be managed other ways, spinal cord injuries affecting bladder control, and critical illness where monitoring fluid output is essential. They’re also sometimes placed during long surgical procedures when the patient is under anesthesia.
In general, healthcare providers try to remove indwelling catheters as soon as possible because the risk of complications rises with every day the catheter stays in place.
Catheter Sizing
Catheters are measured using the French scale, which refers to the outer diameter of the tube. A higher number means a wider catheter. Most adult women use sizes ranging from 12 to 16 French, while most adult men use sizes between 12 and 24 French, with 14 to 18 French being the most common range. The right size depends on your anatomy and the reason for catheterization. A catheter that’s too large can cause more irritation, while one that’s too small may not drain properly.
Living With an Indwelling Catheter
If you’re sent home with an indwelling catheter, daily care focuses on keeping things clean and making sure urine drains freely. You’ll use two types of collection bags: a smaller leg bag strapped to your thigh or calf during the day (which hides under clothing) and a larger bedside bag at night that holds more urine so you don’t need to wake up to empty it.
To empty the bag, you open a valve at the bottom and let the urine drain into a toilet or measuring container. Always wash your hands thoroughly before and after handling the bag or catheter. Clean the area where the catheter enters your body with soap and water once a day, and again after every bowel movement. Don’t apply antibiotic ointment or antibacterial products around the catheter site. Don’t tug on the tubing when cleaning, as this can injure the urethra. Keep the drainage bag below the level of your bladder at all times so urine flows downward and doesn’t back up into the bladder.
Common Complications
The catheter is a foreign object sitting inside your body, and the bladder doesn’t always tolerate it quietly. One of the most common issues is catheter-related bladder discomfort, caused by the tube irritating the bladder wall and triggering involuntary muscle contractions. These bladder spasms can feel like sudden, intense cramping. In some cases, the spasms are strong enough to force urine around the outside of the catheter, a problem called bypass leakage.
Other complications include blockage from mineral deposits (encrustation) building up inside the tube, bladder stones forming around the catheter, blood in the urine from irritation, and urethral injury. The balloon that holds the catheter in place also creates a small pocket of stagnant urine (roughly 10 to 100 mL) at the base of the bladder that can’t drain, which sets the stage for chronic infection.
Infection Risk
Catheter-associated urinary tract infection, or CAUTI, is the most significant risk. National data from U.S. hospitals reported by the CDC show CAUTI rates of 3.1 to 7.5 infections per 1,000 catheter-days. That means for every 1,000 days patients collectively spend with catheters in place, several infections occur. The longer the catheter stays in, the higher your cumulative risk. Bacteria can travel along the outside of the catheter or through the drainage system into the bladder.
Signs of a catheter-related infection include fever, burning or pain in the lower abdomen, a burning sensation when urinating (if any urine passes around the catheter), and urinating more frequently than expected. Changes in urine color, cloudiness, or strong odor can also signal a problem, though these alone aren’t always reliable indicators of infection.
Catheter Removal and Recovery
Removing an indwelling catheter is straightforward. The balloon is deflated by withdrawing the sterile water, and the tube slides out. What comes next is a “trial of voiding,” where your medical team monitors whether you can urinate on your own and fully empty your bladder. In one approach, a small amount of warm saline is infused into the bladder before removal so you feel the urge to urinate soon after the catheter comes out. This method can cut the time needed to determine if you’re voiding successfully by nearly two hours compared to standard removal, and it slightly improves the odds of a successful outcome.
After removal, expect some burning or discomfort for the first day or two, along with a frequent urge to urinate. Your bladder has been drained continuously, so it may need a short adjustment period to regain its normal filling and emptying rhythm. If you can’t urinate within several hours of removal, or if you’re passing only small amounts and feeling fullness, the catheter may need to be reinserted temporarily.