26 January 2024
Nikki Cotterill and Paul Abrams are urology experts and members of the Bladder and Bowel Confidence Health Integration Team (BABCON HIT). Nikki is Professor of Continence Care, University of West of England and Bristol Urological Institute. Paul is Professor of Urology, University of Bristol and Consultant Urological Surgeon, North Bristol NHS Trust. He’s also had post-operative urinary retention (POUR) himself. In this blog they answer commonly asked questions about POUR – which means not being able to have a wee after an operation.
Sometimes after an operation, like a hip replacement, the patient is unable to pass urine. This is known as post-operative urinary retention or POUR. Usually, they have to have a tube called a catheter passed into the bladder to allow it to drain. Research has shown this can affect up to four out of every ten patients following an operation. It’s particularly common in older people having hip or knee replacement surgery.
There are two things that are needed so we know we need to empty our bladder. One is for the bladder to send the signal to our brain telling us it’s full. The second is that our brain needs to receive that signal and decide to empty the bladder.
To empty our bladder our brain sends a signal to the bladder. Again, two things need to happen. First the signal from our brain needs to reach the bladder and second the bladder needs to receive the signal and carry out the instruction to empty.
POUR may happen if there are problems with the bladder, or the brain, or the connections between them. These problems may already exist before the surgery or may be caused by the surgery.
If people already have problems emptying their bladder an operation may be the last straw. Both men and women can already have problems before their operation.
The first, more often in men, is something getting in the way of emptying the bladder properly. The most common cause is an enlarged prostate that makes the bladder work harder to empty. There is a tablet that relaxes the prostate that can be taken before the operation which makes it less likely that POUR will happen.
The second is that for some people their bladder does not squeeze strongly enough to empty normally. An underactive bladder usually has no obvious cause and it can effect both men and women. Unfortunately, there is no tablet to help this condition. Both conditions become more common in older age.
With either of these conditions the person may have noticed a slow flow and may feel that their bladder doesn’t empty fully when they go to the toilet. If that’s the case and the surgeon doesn’t ask, it’s wise for you to tell them about your existing problem.
Again, there are two causes. First is the operation and secondly the anaesthetic.
Bigger operations are likely to cause more pain, meaning you need to be given stronger pain killers. This may mean you don’t realise your bladder needs to empty. If the operation is close to the bladder or its nerves, it may directly affect the bladder and its connections to the brain. So, operations in the lower part of your tummy are more likely to lead to POUR. These will include operations on the bowel or womb.
Anaesthetic is a medicine given to patients to stop them feeling pain during surgery. This can be a general anaesthetic, which puts you to sleep, or a regional anaesthetic which numbs or blocks the feeling in just the part of your body that the surgeon is going to operate on.
A general anaesthetic may cause POUR because when you are asleep you won’t feel your bladder filling up and even when you wake up you may feel woozy for a while and not notice that your bladder is full.
A regional anaesthetic can directly affect the nerves to and from your bladder. For example a spinal or an epidural anaesthetic is often given for operations like hip and knee replacements. These can also affect your bladder so that you don’t feel the need to empty and it overfills.
Of course, both types of anaesthetic wear off after a while. However, the regional anaesthetics take longer. That can be good and bad. Good because they give you great pain relief but bad because they may interfere with your bladder long enough to cause POUR.
The balance of water in your body: During surgery the anaesthetist is responsible for making sure that you have enough liquid in your body as you aren’t allowed to drink. This is quite difficult to judge and can lead to you producing a lot of urine during the operation. If you have a long operation, then your bladder can become overstretched making it more difficult for the bladder to squeeze when you tell it to empty.
Pain relief: After surgery we all want pain relief. The problem is that pain killers not only numb our pain but they have other effects which don’t help us to empty our bladder after the operation. Strong pain killers make us feel nicely drowsy, but that means we can’t feel our bladder so easily. They also make it difficult to get up after the operation. We all know it is easier to empty the bladder when you are standing or sitting, but not when you are lying.
Delayed mobilisation: This means you stayed in bed longer than usual after the operation. All our bodily functions work better if you can be up and moving as soon as possible after surgery. This is why nowadays the hospital staff get you up as soon as possible, as it reduces all sorts of complications.
Before you come in for your operation: Those men and women who have bladder emptying problems before their operation need to be assessed more fully before surgery to see how well their bladder is working. If you think you have problems, you can have simple flow tests and the amount of urine left in your bladder can be measured easily by ultrasound placed on your tummy. Your surgeon can then discuss with you whether you should have some drug treatment before the operation to make it easier to pass urine after the operation.
When you come in for surgery: If you already have a problem with bladder emptying that isn’t helped by tablets then the surgeon may discuss with you whether it’s best to put a tube (catheter) into your bladder until the anaesthetic has worn off and you can get out of bed. This will usually just be one day. The same decision may be suggested if your operation is going to be long and more major.
If everyone had a catheter until they had recovered from surgery and were up and about, POUR would be prevented. However, the simple answer to this question, is because most of us will never need one, and having a catheter isn’t very pleasant and can lead to complications like a bladder infection. So, a catheter should only be used when it’s really needed.
If you can’t pass urine naturally after the operation, then POUR is managed by inserting a tube to drain the bladder, or ‘catheterisation’. Provided your bladder has not overstretched then the catheter should only be needed for 24 to 36 hours. If your bladder has been overstretched then your bladder needs resting for longer, often several days, depending on your individual case.
Paul’s story: I had no urinary problems before my hip replacement, which was more than 10 years ago. The operation was in the morning, and done under combined general and epidural anaesthetic. By the early evening I was able to try to pass urine, but couldn’t. I couldn’t feel my bladder and couldn’t make it work. As my bladder was full, the doctor passed a catheter which was removed in the morning. By that time, I could feel my bladder and had no problem passing urine. So, with the right action my discharge home wasn’t delayed, and I’ve had no further problems since then.
Using a catheter can lengthen hospital stay and lead to more problems such as infections and damage to the bladder. Having a catheter can also mean you are unable to move around and it can make people feel uncomfortable or embarrassed. Some people leave hospital with a tube still in place.
That is possible. However, your doctors will have been alerted to what happened previously and may well suggest that you have a catheter put in when you are anaesthetised. Then it can be removed the next day, if you are fully recovered from the anaesthetic, and up and about and ready to go home.
A review of the research evidence by NIHR ARC West identified possible ways to reduce POUR:
The list of seven possible ways to reduce POUR should be looked at in new research studies as the evidence we found is not strong enough to be sure how to help you as an individual.
Good luck with your surgery and we hope all goes well.