If a catheter is to remain in the bladder for a prescribed period of time, an indwelling catheter will be used.
These are also known as Foley catheters, named after their inventor, Fredrick Foley, in 1934.
Indwelling urinary catheters should be used only after alternative methods of management have been considered.
Before deciding which type of indwelling catheter would suit you best, the nurse or doctor will consider
several key issues:
Length of Indwelling Catheter
Like intermittent catheters, adult indwelling catheters are available in a standard (male) length (40-45cm)
and a shorter female length (20-26cm).
For children, paediatric standard length catheters (approximately 30cm) are available
but if a child requires a size 12ch then a standard (male) or female length catheter should be used.
Catheter Balloon Infill Size
Foley catheters differ from intermittent catheters in that they have an inflatable balloon
at one end and an inflation channel at the other. The purpose of the inflated balloon is
to enable the catheter to be anchored into the base of your bladder for continuous drainage of urine.
The balloon is filled with the correct amount of recommended sterile water inserted through the
inflation channel during the catheterisation procedure.
For adults, the amount of sterile water used to fill the balloon should routinely be 10mls.
However, it is not uncommon for a short-term 30 ml balloon to be used following surgery to
drain away debris and blood clots. Your clinical need for catheterisation should be reviewed
regularly and the urinary catheter removed as soon as possible. If still required, it should
be replaced with one with a smaller 10ml balloon. For children a 3-5ml balloon is commonly used.
Materials & Duration
Materials that the indwelling catheter is made from determine the maximum length of time it can remain in the bladder.
Note: Some may contain latex.
It is important that you tell your nurse and/or doctor if you have a known latex allergy/sensitivity.
Short-Term (Mostly used in hospitals)
E.g. latex and latex bonded with PTFE catheters
Maximum 4 weeks.
Long-Term (Mostly used in the community)
E.g. latex with hydrophilic coating, latex with polymer hydromer coating, latex with silicone elastomer coated catheters and all silicone catheters.
Maximum 12 weeks.
For more information refer to the section entitled “What Does Indwelling Catheterisation Entail?
Diameter
Both intermittent and indwelling catheters are also made in a variety of French gauge (Fr) diameter sizes known as Charrière sizes. To give you some idea, 1 Charrière is equal to 0.33mm. This means that a 12Ch catheter is 4mm and a 16Ch catheter is 5.3mm in diameter.
Average diameters are:
Adult Female: 12-14ch
Adult Male: 14-16ch
Children: 6-10ch with a size 12ch from age 14 years upwards
Of course, larger or smaller sizes can be used following assessment by your healthcare professional.
Taking all these factors into account, it is easier for you to understand the importance, knowledge
and care your healthcare professional exercises to make sure that the most suitable indwelling catheter
is selected for your use.
How is the catheter inserted into the bladder?
Having a basic anatomical understanding of the lower urinary tract will help you to understand how the catheter is inserted into the bladder.
The most common route for catheterisation is via the urethra. The urethra is the anatomical tube that
allows urine to be drained from the bladder to an appropriate external receptacle – normally the toilet.
In women, the urethra is approximately 4 cm long so the catheter doesn’t have far to travel to get into the bladder.
In men the urethra is longer at approximately 18-20cm.