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Catheterization of the Urinary Bladder (Foley Catheterization)

Critical Care

A "Foley" catheter (or thin hollow tube) is placed in the bladder to let urine drain from the bladder. The Foley catheter can help patients who are too ill to pass water on their own. It also helps make sure that all urine is measured in patients who need very careful fluid balance.

Common reasons for its use and benefits:

  • Measurement of urine - In many critical illnesses, the amount of urine that patients make every hour provides an important measure of how they are doing. Even in a patient who is able to pass water, sometimes a Foley catheter is used when it is important to know exactly how much urine that a patient is making every hour.
  • To drain the bladder - In patients who are too weak to get up and pass water on their own or in patients who are unconscious, the Foley catheter drains the urine from the body. Sometimes the bladder becomes weakened by disease or medication and doesn't empty properly. In these situations, the Foley catheter can prevent the excessive build up of urine in the bladder, which can be uncomfortable.


Some of the risks of Foley catheterization include:

  • Infection - The most common risk of Foley catheter placement is infection. Bacteria can move up the catheter, pass into the bladder, and cause infections. The longer the Foley catheter remains in place, the higher is the likelihood of an infection. Care is taken with the tube and drainage system to prevent infection but it can occur even when everything is done correctly. Infections can usually be treated with antibiotics.
  • Injury to Urethra - During the insertion of the catheter, the urethra (the tube that leads to the bladder) can be injured or punctured. This complication is rare and usually it heals on its own without treatment.

Because of the low risk and common need for this procedure, the consent that patients sign for general treatments at the time of coming into the hospital usually includes permission for placement of the Foley catheter if it is needed.

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Foley Catheter The tip of the catheter (shown by the arrow) is coated with jelly to make it easier to pass through the passage that leads into the bladder.