Urinary catheterisation is a medical procedure used to drain and collect urine from the bladder.
A thin flexible tube called a catheter is inserted into the bladder, usually along the urethra, the tube through which urine passes (urethral), or through a hole in your abdomen directly into the bladder (suprapubic).
The catheter usually remains in the bladder, allowing urine to flow through it and into a drainage bag.
Why is urinary catheterisation needed?
A urinary catheter can be used on a short- or long-term basis.
Short-term catheterisation
Short-term catheterisation may be needed to remove urine from the bladder for a short period of time if there is something stopping you emptying your bladder in the normal way.
For example, if the bladder cannot empty due to an obstruction (blockage), or if it is unable to generate enough force to propel urine down the waterpipe.
If the urethra has become blocked, it may be due to scarring (stricture), prostate enlargement (benign or malignant) or, rarely, a bladder stone. A catheter will be fitted until the underlying condition can be confirmed and treated.
Short-term catheterisation may also be used in preparation for some types of surgery where decompression (expansion) of the bladder is useful, such as operations on the womb or ovaries and procedures involving the large bowel.
Other operations where a long period of recovery is anticipated may also involve fitting a catheter so that the urine output of someone who is unconscious or recovering from surgery can be monitored.
Other situations where a catheter may be used include during childbirth (to drain the woman's bladder), and to clear the bladder of any blood clots and debris following an injury to the bladder or after surgery to that area.
Long-term catheterisation
A urinary catheter may be needed on a long time basis if there is an obstruction in the urinary tract, such as a swollen prostate gland (in men), scarring to the water pipe (urethral stricture) or, rarely, a stone, and it is not possible to use medication or surgery to remove the obstruction.
Long-term catheterisation is also sometimes used when a person is confined to bed and is too weak to go to the toilet in the normal way.
It is also sometimes used as a treatment for urinary incontinence (the involuntary passing of urine) when all other types of treatment have failed.
Another reason why long-term catheterisation may be used is to remove urine from the bladder if a person is unable to control their bladder either due to nerve damage (neuropathic bladder), or bladder weakness (detrusor hypocontractility) that does not respond to other treatments
If you require urinary catheterisation for a long time, you may be trained to insert catheters to empty your bladder when needed.
This is known as self-catheterisation and involves catheterisation for a short period to allow the bladder to empty before the catheter is removed. This process may need to be carried out several times a day and avoids the problems associated with permanent catheterisation.
Other uses
In some cases, catheters are used for reasons other than removing urine from the bladder due to a problem with the urinary tract.
For example, a urinary catheter can be used to obtain a clean urine sample to test for bacterial infections. A clean urine sample is a sample that has not been contaminated by bacteria from your hands or genitals.
A catheter can also be used to deliver medication directly into the bladder. For example, chemotherapy medications can be placed into the bladder through a catheter to treat cancer of the bladder.
Types of catheters
There are two main types of catheter. They are:
- an intermittent catheter - where the catheter is temporarily inserted into the bladder and removed once the bladder is empty
- an indwelling catheter - where the catheter remains in place for many days or weeks
Most people prefer to use an indwelling catheter because it is much more convenient and causes less pain than using an intermittent catheter.
However, if a catheter is needed on a long-term basis, an intermittent catheter will have to be used. This is because the longer an indwelling catheter is in place, the higher the risk of it causing an infection.
Read more about how urinary catheterisation is carried out.
Risks
The main disadvantage of using a urinary catheter is that it can sometimes allow bacteria to enter the body.
This can cause an infection in the urethra, bladder or (less commonly) kidneys. These types are known as urinary tract infections (UTIs).
UTIs from catheter use are the most common type of infection to affect people staying in hospital, accounting for around a third of cases.
Because of the relatively high risk of infection, a urinary catheter should only be used when there is no alternative method of emptying the bladder.
Read more about the risks of catheterisation.
