The Foley Catheter: Use and Technique

The Foley Catheter is also called a urinary catheter. It's a tube that allows one's urine to exit from the bladder into a drainage bag. 
The Foley Catheter: Use and Technique
Nelton Abdon Ramos Rojas

Written and verified by the doctor Nelton Abdon Ramos Rojas.

Last update: 27 May, 2022

The Foley Catheter is another name for the urinary catheter. It’s a tube that allows one’s urine to exit from the bladder into a drainage bag. 

The Foley catheter is a type of flexible catheter that drains urine from the bladder to the outside. For this reason, it’s also known as a urinary catheter or a bladder catheter.

The tube is usually latex, since this material is more comfortable for patients. However, if the person is allergic to latex, there’s another type of plastic that manufacturers use to maintain the sterility of the catheter. This will help to prevent infections. 

Additionally, it should be noted that these catheters are named after Dr. Foley, an American surgeon. As we’ll explain later, patients commonly use them in the medical world.

How is it designed?

A lady with stomach pain.

The doctor inserts the Foley catheter through the urethra in order to reach the bladder. Therefore, it has to be able to adapt to different sizes. That’s why there are a variety of different tubes for men, women, and children. Additionally, there are also different thickness gauges so that they can better adapt to the particularities of the anatomy of each patient. 

There’s a scale that describes the size of the catheters. It’s the French scale of Charriere, where one unit equals 13 inches.

The number of the Charriere units is equivalent to the size of the circumference of the catheter in millimeters. That means, using the number of Cherriere units (represented by the symbol F), we can know the diameter of the catheter and, therefore, the urethra. 

Despite the array of catheters, they all have something in common. They all have a balloon attached to the tube that comes deflated.

The balloon is the crucial part of the Foley catheter. This part helps it to function correctly since it’s the only element of the design that keeps the catheter from detaching.

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How do you place the Foley catheter?

Before inserting it, make sure that the catheter isn’t defective. Nowadays, manufacturing houses carry out very strict quality controls. However, even so, it isn’t uncommon to come across a catheter that has a simple defect.

To check that the catheter works, you should put some sterile water into the nozzle that’s located in the balloon. If the balloon starts to swell and there are no water leaks, then the catheter can be used on the patient.

Remember, the patient’s genitals must be perfectly clean. Using a little lubricant, the doctor carefully inserts the catheter through the urethra. To make it easier to put the tube into the bladder, you can add abdominal pressure using different breathing maneuvers or by stimulating urination.

Once the tube is inside the bladder, the balloon has to fill to keep the tube from coming out. Using a syringe, the balloon fills with air or sterile water using the nozzle with the small valve.

Finally, the catheter’s valve itself is connected to a bag where the urine is stored. To facilitate volume measurement, there are also graduation marks on the bag, usually in millimeters.

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What is it used for?

A man near a toilet.

The most common uses for the Foley catheter are:

  • Urinary incontinence: this is common in the elderly and in patients who have suffered neurological damage in which the nerves responsible for urination are damaged.
  • Any situation that prevents the complete emptying of the bladder: such as prostate cancer. 
  • Patients who have undergone surgery and have to control the volume of urine expelled.

What are the drawbacks?

The main problem when using the Foley catheter is the risk of a urinary infection. The catheter is still a foreign body in an area where bacteria can come in from the outside of the genitals into the bladder. That’s why you must pay close attention to hygiene in this area.

In addition, it’s important to prevent the drainage bag from twisting so that urine flows uninterrupted and it won’t accumulate. A simple way to do this is to fix the catheter in place by taping it to your thigh. On the other hand, if the patient is bedridden, you can leave the bag under the bed so that the urine will flow in favor of gravity.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

  • Catéter de Foley. (s.f.). En Wikipedia. Recuperado el 14 de diciembre de 2018 de
  • Rueda S, Pérez FJ, P. M. (2013). Protocolo de Sondaje Vesical: Modificación de la técnica para cambio de catéter en portadores de larga duración. Nure Investigación.
  • Tailly T, Denstedt JD. Fundamentals of urinary tract drainage. In: Wein AJ, Kavoussi LR, Partin AW, Peters CA, eds. Campbell-Walsh Urology. 11th ed. Philadelphia, PA: Elsevier; 2016:chap 6.

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.