Foley catheter

In urology, a Foley catheter (named for Frederic Foley, who produced the original design in 1929) 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 lumina (sg. lumen), 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. Foley catheters 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 or even diminished while carrying catheters. The name comes from the designer, Frederic Foley, a surgeon who worked in Boston, Massachusetts in the 1930s. His original design was adopted by C. R. Bard, Inc. of Murray Hill, New Jersey, who manufactured the first prototypes and named them in honor of the surgeon. Foley catheters come in several types: Coudé (French for elbowed) catheters have a 45° bend at the tip that facilitates easier passage through an enlarged prostate. Councill tip catheters have a small hole at the tip so they can be passed over a wire. Three-way, or triple lumen catheters have a third channel used to infuse sterile saline or another irrigating solution. These are used primarily after surgery on the bladder or prostate, to wash away blood and blood clots. The relative size of a Foley catheter is described using French units (F).