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Indwelling Urinary Catheters

09 January 2013

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 possible⁵´⁶⁺⁷. If still required, it should be replaced with one with a smaller 10ml balloon.  For children a 3-5ml balloon is commonly used. See figure below
 
(Figure 1)
Indwelling (Foley) Urinary Catheter

Materials & Duration
 
Materials that the indwelling catheter is made from determine the maximum length of time it can remain in the bladder.  ²´⁵´⁶⁺⁷
 
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. (See figure below).
 

(Figure 2)
Urinary System


What does indwelling catheterisation entail?

A Foley indwelling catheter differs from an intermittent catheter  in that it is designed to include a balloon at one end and an inflation channel at the other end through which the appropriate amount of sterile water is inserted to inflate the balloon.

(Figure 3)
Indwelling (Foley) Urinary Catheters Male and Female Diagram
 
 
Indwelling urinary catheters should be used only after alternative methods of management have been considered⁵´⁶⁺⁷. They can be inserted into the bladder either urethrally or suprapubically . All catheterisations carried out by your healthcare worker should be carried out as an aseptic procedure.  In some instances, the Nurse may teach the patient or carer how to replace an indwelling catheter with a new one if change is due, blockage occurs, or the catheter is expelled unexpectedly.
 
Note:  You should never attempt to remove the catheter yourself whilst the balloon is inflated.  If problems are experienced you should contact your nurse immediately.
 
Other aftercare procedures such as emptying the urine collection bag and changing it , for example, will routinely be shown to the patient and/or carer.  You will find further details on how to care for your catheter and yourself as you progress through the text.
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