Urologic Catheters: Indwelling | Intermittent | External
Indwelling urinary catheters are soft, flexible tubes that have double lumens, or separate channels, running down it lengthwise. One of the lumen is open at both ends and allows for urine drainage by connection to a drainage bag.
The other lumen has a valve on the outside end and connects to a balloon at the tip; the balloon is inflated with sterile water when it lies inside the bladder, and allows for retention iin the bladder. These are known as two-way catheters.
The name of the Foley catheter comes from the designer, Frederic Foley, a surgeon working 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.
The relative size of a Foley catheter is described using French units (Fr). The most common sizes are 10 Fr to 28 Fr. 1 Fr is equivalent to 0.33 mm = .013" = 1/77" in diameter.
Three-way catheters are available with a third channel to facilitate continuous bladder irrigation.
This catheter is primarily used following urological surgery or in case of bleeding from a bladder or prostate tumor and the bladder may need continuous or intermittent irrigation to clear blood clots or debris.
Catheters are fairly rigid structures. They drain the bladder but block the urethra. The catheter should have a smooth surface with two drainage eyes at the tip that allow for urine drainage.
Drainage eyes are placed either laterally or opposed. Opposing drainage eyes generally facilitate better drainage.
Catheter products have changed significantly in their composition, texture, and durability since the 1990s.
The challenge is to produce a catheter that matches as closely as possible to the normal physiological and mechanical characteristics of the voiding system. Foley catheters come in several subtypes, which are described in the area designs.
Jahn P, Beutner K, Langer G. Types of indwelling urinary catheters for long-term bladder drainage in adults. Cochrane Database of Systematic Reviews 2012, Issue 10. Art. No.: CD004997. DOI: 10.1002/14651858.CD004997.pub3.