In urology, a Foley catheter is a flexible tube that a clinician passes through the urethra and into the bladder to drain urine. It is the most common type of indwelling urinary catheter.
The tube has two separated channels, or lumens, running down its length. One lumen, open at both ends, drains urine into a collection bag. The other has a valve on the outside end and connects to a balloon at the inside tip. The balloon is inflated with sterile water when it lies inside the bladder to stop it from slipping out. Manufacturers usually produce Foley catheters using silicone or coated natural latex. Coatings include polytetrafluoroethylene, hydrogel, or a silicon elastomer – the different properties of these surface coatings determine whether the catheter is suitable for 28-day or 3-month indwelling duration.
A section cut of the distal end of a Foley catheter. The image shows a burst balloon, balloon lumen, and main drain lumen.
Foley catheters should be used only when indicated, as useing increases the risk of catheter-associated urinary tract infection and other adverse effects.
Indwelling urinary catheters are most commonly used to assist people who cannot urinate on their own. Indications for using a catheter include providing relief when there is urinary retention, monitoring urine output for critically ill persons, managing urination during surgery, and providing end-of-life care.