Catheter

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 tube urine naturally passes through (urethral catheter), or through a hole in your abdomen directly into the bladder (suprapubic catheter).

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 normally.

For example, this could be because the bladder cannot empty if there is an obstruction (blockage) or it is unable to generate enough force to propel urine down the waterpipe.

If the urethra has become blocked, it may be because of scarring (stricture), prostate enlargement, or, rarely, a stone. A catheter will be fitted until the underlying condition can be treated.

Short-term catheterisation may also be used in preparation for some types of surgery, such as operations on the womb or ovaries and procedures involving the large bowel. It may also be used for other operations where a long period of recovery is anticipated.

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 for a long time if it's not possible to treat the underlying condition that prevents the bladder from emptying naturally.

Long-term catheterisation can be used when a person is confined to bed and is too weak to go to the toilet. It is also sometimes used as a treatment for urinary incontinence when other types of treatment have failed.

If a person is unable to empty their bladder because of bladder weakness (detrusor hypocontractility) or nerve damage (neurogenic bladder), long-term catheterisation is a possible treatment option.

If you require urinary catheterisation for a long time, you may be trained to insert a catheter 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 is likely to be carried out several times a day and avoids the problems associated with permanent catheterisation.

Other uses

In some cases, catheters can be used to obtain a clean urine sample to test for bacterial infections. This 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, such as chemotherapy medications used to treat cancer of the bladder.

Types of catheters

There are two main types of catheter. They are:

intermittent catheter – where the catheter is temporarily inserted into the bladder and removed once the bladder is empty
indwelling catheter – where the catheter remains in place for many days or weeks and is held in position by a water-filled balloon in the bladder

Many people prefer to use an indwelling catheter because it is more convenient. However, indwelling catheters can be complicated by problems such as bladder spasm, infection, blockage and leakage around the catheter. These problems are reduced if intermittent catheterisation is used.

How does it work?

Different types of urinary catheter work in different ways.

Intermittent urinary catheter

An intermittent urinary catheter is inserted just long enough to drain your bladder before being removed. It may be used up to four to six times a day.

It can be inserted yourself in a process known as clean intermittent self-catheterisation (CISC), which avoids the need for an indwelling catheter. This technique is usually taught to patients by a continence nurse.

The catheter is usually inserted into your bladder via the urethra (the tube urine passes through out of your body). The sterilised catheter is lubricated with a sterile gel and a local anaesthetic cream or gel may be applied to numb the opening of your urethra, although this is not usually necessary.

One end of the catheter is either left open-ended to allow drainage into a toilet or attached to a bag to collect the urine. The other end is inserted into your urethra and guided through it until it enters your bladder and urine starts to flow.

When the flow of urine stops, the catheter can be moved or rotated. You may need to change positions to ensure all the urine has been emptied from your bladder. The catheter can then be removed. A new catheter is likely to be used each time.

Indwelling urinary catheter

An indwelling urinary catheter is inserted in the same way as an intermittent catheter, but the catheter is left in place.

Most indwelling catheters are not suitable to remain in place for longer than three months, so will need to be changed regularly.

The catheter is held in the bladder by a water-filled balloon, which prevents it falling out. These types of catheters are often referred to as Foley catheters.

Urine is drained through a tube connected to a collection bag, which can either be strapped to the inside of your leg or attached to a stand on the floor.

Indwelling catheters are not always free-draining and the catheter is sometimes fitted with a valve. The valve can be opened to allow urine to be drained into a toilet and closed to allow the bladder to fill with urine until drainage is convenient.

Suprapubic catheterisation

A suprapubic catheter is a type of indwelling catheter. Rather than being inserted through your urethra, the catheter is inserted through a hole in your abdomen and then directly into your bladder. This procedure can be carried out under general anaesthetic or local anaesthetic.

A suprapubic catheter is used when the urethra is damaged or blocked, or when a person has a long-term condition and is unable to use a clean intermittent catheter.

The catheter may be taped to the side of your body and run down to a collection bag strapped to your leg. Alternatively, a valve can be attached that opens to allow urine to be drained into a toilet, and closes to allow the bladder to fill with urine until drainage is convenient.

The catheter will need to be changed regularly and is not usually left in place for more than three months.

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, the kidneys. These types of infection are known as urinary tract infections (UTIs).

Urinary tract infections (UTIs)

UTIs resulting from catheter use are the most common type of infection affecting people staying in hospital.

Despite high hygiene standards in most modern hospitals, about 1 in 10 people who have a catheter develop a UTI.

Because of the high risk of infection, a urinary catheter is only used when there is no alternative method of emptying the bladder.

The risk of infection increases if your catheter is left in place continuously (an indwelling catheter). Most people with an indwelling catheter will have bacteria in their urine, although this isn't the same as a urine infection, which causes the symptoms described below.

If you insert a catheter yourself intermittently, it's important you receive training from your care team.

Symptoms of a catheter-associated UTI include:

pain in the bladder or urethra (the tube urine passes through out of your body)
offensive-smelling discharge from the urethra
passing foul-smelling, cloudy urine
general symptoms of an infection, such as a high temperature of 38°C (100.4°F) or above
a feeling of being generally unwell, tired and lethargic (lacking in energy)

Other risks

Bladder spasm, which feels like abdominal cramp, is quite common when you have a catheter in your bladder. The pain is caused by the bladder trying to squeeze out the balloon. Medication may be necessary to reduce the frequency and intensity of the spasms.

Leakage around the catheter is another problem associated with indwelling catheters. This is called by-passing and can occur as a result of bladder spasms or when you open your bowels. Leakage can be a sign that the catheter is blocked, so it's essential to check that the catheter is draining.

Blood or debris in the catheter tube is also fairly common with an indwelling catheter. This could become a problem if the catheter drainage system becomes blocked.