Biomaterial of the Month


Date: November 10, 2006
Tom Webster (

Urinary Catheter

Definition: A urinary catheter is any tube system placed in the body to drain and collect urine from the bladder.
Alternative Names: How to insert a catheter; Suprapubic catheters; How to remove a catheter; Foley catheter
Information: A Foley catheter is a soft plastic or rubber tube that is inserted into the bladder to drain the urine. Urinary catheters are sometimes recommended as a way to manage urinary incontinence and urinary retention in both men and women. There are several different types of catheters which may be used for a variety of different reasons.

Urinary catheters may be used to drain the bladder. This is often a last resort because of the possible complications associated with continuous catheter usage. Complications of catheter use may include: urinary tract and/or kidney infections, blood infections (septicemia), urethral injury, skin breakdown, bladder stones, and blood in the urine (hematuria). After many years of catheter use, bladder cancer may also develop.

Your health care provider may recommend use of a catheter for short term use or long term use (indwelling). The catheter may be left in place during this time, or you may be instructed on a procedure for placing a catheter just long enough to empty the bladder and then remove it (clean intermittent self catheterization).

Catheters come in a large variety of sizes (12 Fr., 14 Fr.,... 30 Fr.), materials (latex, silicone, Teflon) and types (Foley catheter, straight catheter, coude tip catheter). It is recommended that you use the smallest size of catheter, if possible. Commonly, a size 14 Fr. or size 16 Fr. catheter is used. Some people may require larger catheters to control leakage of urine around the catheter or if the urine is thick and bloody or contains large amounts of sediment. Be aware that larger catheters are more likely to cause damage to the urethra. Some people have developed allergies or sensitivity to latex after long term latex catheter use; these people should use the silicone or Teflon catheters.

A catheter that is left in place for a period of time may be attached to a drainage bag to collect the urine. There are two types of drainage bags. One type is a leg bag, which is a smaller drainage device that attaches by elastic bands to the leg. A leg bag is usually worn during the day since it fits discreetly under pants or skirts, and is easily emptied into the toilet. The other type of drainage bag is a larger drainage device (down drain) that may be used during the night. This device is usually hung on the bed or placed on the floor.

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