Foley catheter

In urology, a Foley catheter is one of many types of urinary catheter (UC). The Foley catheter was named after Frederic Foley, who produced the original design in 1929. A Foley catheter is an indwelling UC, often referred to as an IDC or sometimes IDUC. This is in contrast to in/out catheters, which have a single tube and no valves, and are designed to go into the bladder, drain it, and come straight back out. A UC comprises a flexible tube if it is indwelling and is intended to remain in place, or made of rigid materials (glass or plastic) if it is the in/out type. In use, a clinician or, often, the patient themselves in the case of in/out UC, passes the device through the urethra and into the bladder to drain urine.

Foley and similar brand catheters usually have two separated channels, or lumina (or lumen), running down their length. One lumen, with opening at each 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 or saline while inside the bladder to prevent it from slipping out. A "three-way" urinary catheter has three lumens and thereby permits bladder washouts, such as are required post prostate surgery: the additional lumen is for saline flow in (bladder washout solution), the other two being for urine flow out and balloon inflation as in the two-way variety.

Manufacturers usually produce Foley catheters using silicone or coated natural latex. Coatings include polytetrafluoroethylene, hydrogel, or a silicone elastomer – the different properties of these surface coatings determine whether the catheter is suitable for 28-day or 3-month indwelling duration.

Indwelling catheters/IDCs should be used only when indicated, as use increases the risk of catheter-associated urinary tract infection (UTI) and other adverse effects. While female sex is generally recognised as a risk factor for UTIs, the differences in biological sex are reduced while carrying catheters.