We are interested in looking at what we call the 21st Century catheter. When one considers what has happened in the last twenty, thirty years in the field of surgical implants, we’ve seen an amazing revolution. When I was a student, one couldn’t replace hip joints or knee joints, but this is now a regular feature and so many people are living with new hip and knee joints. We have people being given new heart valves. And we have people whose cataract is removed and you have implant lenses put into the eye. it’s a remarkable transition from what was available in the past.

But we are still using a urinary catheter that was developed in the 1930s at a time when medicine was very empirical. It wasn’t based on scientific evidence. I tried to explain to you that the bladder has a remarkable anti-bacterial defence mechanism and this relies on its ability to fill and empty completely, and also on the preservation of that lining of the bladder, preventing bacteria from attaching to the cells on that surface.

Now the Foley catheter, as I’ve explained, does prevent complete emptying of the bladder. Bacteria get into the bladder and they multiply very rapidly in urine. it’s a very good culture medium for bacteria. They rapidly multiply and the tip of the catheter will damage the surface, that mucin surface that lines the bladder, and also ulcerate the surface. So then the bacteria can get into the wall of the bladder and, once they are in the wall of the bladder, they can reach the blood stream. So serious infections can follow in certain circumstances.

I think we need a new design of catheter which supports those anti-bacterial defence mechanisms, that we store the urine in the bladder, not in a bag on the leg. The bladder in most cases can store the urine perfectly well but we need some mechanism to allow the bladder to be drained. We want to make sure that no damage is done to the lining of the bladder.

Modern technology is advancing so rapidly we should have a catheter valve that could be controlled by remote control for those people who have poor manual dexterity or even on an automatic timed mechanism for those who don’t have the cognitive ability to be able to drain their own bladder.

Unfortunately, there are too many people who have to rely on catheter drainage of the bladder because of their condition and I think that we, our technology today should be addressing these problems more actively.

One of the most common complications with a long term catheter is recurrent blockage of the catheter.

Now this is in an interesting problem because there are certain bacteria, particularly one known as proteus mirabilis which contains an enzyme termed urease. Now urea is the end product of protein metabolism in the body and urease hydrolyses urea to form ammonia.

Under these circumstances the acidity, the pH of urine rises from about, normally about 7 and it rises up to 7.3, 7.5 even 7.8 and as the pH rises so the phosphates in the urine come out as solution and they form crystals. Calcium hydroxyapatite and calcium struvite crystals are formed on the catheter and within the catheter, and this blocks the catheter and the drainage. And so recurrent blockage with proteus infections is a major problem for the patient.

Blocking of catheters and by-passing of urine around the catheter as a result of blockages are the most common complications and they keep the district nurses really quite busy. 4% of the district nurses duty, so to speak, is spent dealing with catheters and that’s quite a high percentage for just one problem.

Could you talk a little bit about the more serious side effects of having a catheter.

As I’ve explained, having a long term catheter, and by long term we’re talking about people who have a catheter for more than 30 days. They are at risk of infection. Infection meaning bacteria get into the blood stream, we talk about bacteraemia, but if this becomes septic then they talk about septicaemia. And they can become very ill as a result of serious infection developing with the bacteria reaching other parts of the body. And there is occasional mortality as a result of septicaemia. But that is rare.

What can patients do to try to prevent these infections?

I think the most important thing that patients do is to maintain a high fluid intake. We try and encourage them to drink up to 3 litres of fluid a day. The other interesting point is that they can reduce the risk or encrustation of the catheter if they drink citrates. And that alters the pH at which these crystals come out of solution. And we encourage them to drink a high proportion of citrate with their fluids.

What sort of drinks would those be?

Well thinks like Lemon Barley and Lemonade and those sort of things will help them.

But not orange?

As long as it contains citrate.

I think that many people who have long term catheters do find that quite regularly they feel off colour for two or three days, they feel unwell. They may feel hot and sweaty. We call that a rigor when they shiver and they feel cold but they are shivering and that’s termed a rigor. And this is not an uncommon experience amongst some patients and this a reflection of the infection that maybe circulating in the blood stream.

Under those circumstances, they need treatment and they need it to be treated with antibiotics. But we do try to avoid antibiotics because whenever you give antibiotics there’s the risk of resistance, of the bacteria developing resistance to antibiotics. So we avoid them at all costs. Far better to keep drinking and try and wash out the bacteria from the bladder.

A Mitrofanoff is a very interesting procedure where the appendix is used as a catheterisable conduit. The appendix is used just as a track between the bladder and the anterior abdominal wall, rather like a suprapubic. But it is continent. It doesn’t leak urine. And so that you can teach somebody to catheterise this track and they remain continent. That is in cases where the bladder fails to empty completely.

And what is the advantage of doing it through that passage rather than through the urethra?

Well quite a large percentage of women find urethral catheterisation distasteful and difficult. Anatomically it can be difficult and they would much prefer to perform catheterisation suprapubically than through the natural urethra.

The Mitrofanoff was developed with reconstructive surgery of the bladder and, in some cases, people have had the bladder removed. A bladder has been constructed from using small or large intestine, and the appendix is used as the conduit which drains this artificial bladder.

Is that quite successful?

It is, oh yes. Some people manage this extremely well. And it’s been a successful procedure.

How do you decide where exactly to insert the suprapubic catheter? Do you have a discussion with the patient about that beforehand?

Well there’s not a great deal of choice where you put the suprapubic catheter in. It just has to be above the pelvic bone, about 2 centimetres above the pelvic bone and you have to make sure that the bladder is filled under the abdominal wall. That’s one of the most important aspects because if, for example, they’ve had abdominal surgery and there’s a scar in that area, you may have bowel stuck down behind the scar and there is a risk, a serious risk, that you may penetrate the bowel when putting in the catheter.

So there are very clear rules, so to speak, for the clinician to follow before he puts in a suprapubic catheter.

There are two ways of putting a catheter in the bladder, either through the urethra, through the natural passage, or it can be put through the lower abdomen as a result of a minor surgical operation. It can be performed in many cases under local anaesthetic.

If a patient has to have a catheter permanently, a lifelong catheter, then there are many advantages for them and their carers to have a suprapubic catheter. As I’ve said already, the male urethra is 18 centimetres long and it’s lined by glands, and the catheter will block these glands and you can get infections in these glands. When the catheter is changed, the catheter tip can damage the surface of the urethra and problems can arise as a result.

The suprapubic catheter is more comfortable for patients and it is easier to manage for the carer or the clinical team in many cases. But it’s a matter of choice very often from the patient and it’s very simple. If they do have a suprapubic catheter put in, if it comes out, the opening into the bladder very rapidly closes actually, so that it soon heals. It isn’t, so to speak, a final irreversible operation.

Are there any disadvantages of having a suprapubic catheter?

If you ask patients who have had both, most people will say they find a suprapubic catheter much more comfortable than having a urethral catheter. They don’t get the irritation. Males for example, if they have a urethral catheter, it can cause irritation. It can cause erections and difficulties from that point of view and they’re free from those sorts of complications if they have a suprapubic.

If a catheter became blocked, would you try to unblock it using a washout before changing it?

Yes, you can. No, I think the most straightforward thing is to change the catheter and get rid of it because as soon as you put a catheter in the bladder, a film forms on the surface of the catheter. We call it a conditioning film. And bacteria then attaches itself onto the surface of the catheter to form what we call a bio film. it’s in that bio film, especially if the proteus mirabilis organism is there, that we get these calcific deposit’s forming.

And if the catheter blocks as a result of encrustation, the best thing to do is to take it out and put in a clean catheter. And then maintain a high fluid intake and to drink those citrated fluids in order to reduce the risk of catheter encrustation.

People must realise with a suprapubic catheter that, if it does come out, if there’s a failure of the balloon as that can occur occasionally and the catheter comes out from the suprapubic track, then that track will close down very rapidly. And it is important that they can re-insert the catheter as soon as possible and just strap it in the bladder before that track closes itself quite spontaneously.

So do you encourage your patients to find out how to do it themselves or get a carer to do it?

Yes, I think that’s very important. I think it’s important that a patient with a suprapubic catheter does have a spare catheter available. And if it does fall out that they can re-insert it. Ideally the patient or their carer can re-insert the catheter.

But the suprapubic catheters do cause some nurses some concern. They are reluctant, for example, to change the catheter because they don’t feel very confident about the suprapubic catheter. This is a matter of training and, on the other hand, one’s known nurses who will put in suprapubic catheters under local anaesthetic and that’s, as I’ve explained before, is a minor operation. Which it can be quite routine as long as the rules are followed carefully. But it needs to be carefully taught how to do it.

The catheter can be drained either continuously into a urine collection bag or one can use a catheter valve and drain the bladder intermittently. The advantage would be to use, for the patient, would be to use a catheter valve to drain the bladder and, in those circumstances then, they don’t have to wear a urine collection bag. But they do need good manual dexterity and they need to have good cognitive ability too.

Many people have a catheter because they are unconscious maybe, or they are undergoing surgery and you are having to monitor their urinary output under these circumstances. But if the bladder is being drained for somebody who’s developed retention of urine, then a catheter and a catheter valve was very much easier for the patient than having to wear a urine collection bag on the leg.

The catheter valve, it’s quite crude. But this is known as a flip flow valve and this fits into the end of the Foley catheter. And this can be just drained. The flip flow catheter can just be drained by turning this lever. That is the catheter valve fitted into the end of the Foley catheter, just like that. And it comes out and can be fitted into the end of the catheter.

What can patients do to try to prevent these infections?

I think the most important thing that patients do is to maintain a high fluid intake. We try and encourage them to drink up to 3 litres of fluid a day. The other interesting point is that they can reduce the risk or encrustation of the catheter if they drink citrates. And that alters the pH at which these crystals come out of solution. And we encourage them to drink a high proportion of citrate with their fluids.

What sort of drinks would those be?

Well things like Lemon Barley and Lemonade and those sort of things will help them.

But not orange?

As long as it contains citrate.

There is a very large variety of bags on the market. All sorts. There are belly bags you can use in some cases, and some people prefer to have a bag on the belly than one on the leg. Some people don’t like the sloshing around of the urine in the bag which disturbs them. And you have various mechanisms that stop that sloshing in the bag. There’s a bag for everyone if you know what I mean. They can look around to find one that will suit them best.

And how often do you think bags should be thrown away?

A bag could last up to a week. As I’ve said, the most important thing is to maintain the closed urine drainage system. And that’s very important. We don’t like the catheter being disconnected from the bag any more often than necessary.

The alternative to the catheter valve is a urine collection bag. This is normally worn on the leg if the patient is ambulant and able to walk around. So this is the leg bag, urine collection bag and these straps go around the calf of the leg.The problem with the urine collection bag is it fills with urine and, as it fills with urine, it becomes heavier and, as it becomes heavier, it can tend to slip down the leg. So there are various forms of device that maintain it on the leg. One is using a sleeve and they can tuck it into a sleeve, rather like a stocking.

Is a sleeve also fixed to the leg?

Yes.

Or to the clothing?

No, it’s like a sock, worn on the leg. The bag fits into the sleeve on the leg and that is an alternative to using the leg straps.
Now the advantage to, in some of these cases where the most important aspect when you have a catheter in is make sure that these junctions do not come apart. We talk about the closed urine collection system. That means there is a closed system from the bladder through the catheter into the urine collection bag. And we do try to prevent any dislocation between the catheter and the leg bag. If we can keep that closed system we reduce the risk of infection developing.
Of course at night, when people are asleep, they will need a larger capacity bag and, under those circumstances, you can use a night bag such as this one, which is a 2-3 litre bag, which can fit onto the end of the leg bag.

That’s good.

A very large capacity from the leg bag into the night bag.

Could you hold that up once more?
This, so we have the catheter, shall I just try andto demonstrate this, we have the catheter with the balloon blown up in the bladder. The catheter is attached to the leg bag through tubing. And then the leg bag can be attached to a night bag which has a much larger capacity and so there is no disturbance of having to empty the bag during the night.

Do you recommend that people do any regular bladder washouts, or only when they get blocked?

No, we prefer not to use bladder washouts in fact. They have been used in the past but they can also damage the surface of the bladder. They can wash off the surface cells of the bladder and so if it’s contentious, a very contentious point whether to use bladder washouts or not.

If a catheter became blocked, would you try to unblock it using a washout?

Yes, you can. Yes, of course

Before changing it?

No, I think the most straightforward thing is to change the catheter and get rid of it because, as soon as you put a catheter in the bladder, a film forms on the surface of the catheter. We call it a conditioning film. And bacteria then attaches itself onto the surface of the catheter to form what we call a biofilm. And it’s in that bio film, especially if the proteus mirabilis organism is there, that we get these calcific deposit’s forming.

And if the catheter blocks as a result of encrustation, the best thing to do is to take it out and put in a clean catheter. And then maintain a high fluid intake, and to drink those citrated fluids in order to reduce the risk of catheter encrustation.

The size of the catheter that is used to drain the bladder is an important aspect of bladder drainage. Over the past few years, we have turned to using much smaller diameter catheters than we did 20, 30 years ago. The urethra, for example, which is the conduit that leads from the bladder to the exterior, that collapses really rather like a fireman’s hose. But we put in a big tube which keeps it distended and affects its blood supply.

We want something that will allow the urethra to collapse and not remain distended. I think we should be using quite small diameter catheters. The catheter gauge is what we term the French gauge. Now that the French gauge 12 catheter, that’s the circumference of the catheter. That means the diameter is about ? of that, is about 4 millimetres. And we should be using those smaller diameters. When I was a medical student we were using catheters of sort of 24 or even 26 French gauge, so they were much wider and much more damaging than these smaller catheters.

The Foley catheter is retained in the bladder by means of a balloon and this is filled with 5 to 10 millilitres of sterile water. Attached here with a side arm and a balloon is distended, and that is what retains the catheter in the bladder. The problem here is that the eye holes are at the tip of the catheter at the top here, and the balloon will be at the base of the bladder. So inevitably it’s leaving a little pool of residual urine in the bladder. Now the bladder also has a tip which can damage that mucin coating within the bladder. And we are concerned that that is maybe one of the causes for the high instance of infections that develop with this catheter.

What other materials are used to make catheters these days?

A wide variety of materials have been used. Silicone has been popular. Silicone tends to be a little bit stronger than the plastic catheters and the advantage is that you have a thinner wall and a wider lumen to the catheter itself.

There have been many attempts in recent years to find a coating which is anti-bacterial, and silver alloy has been used. But the results so far have not shown any convincing advantages of these more expensive catheters. But people have been seeking for a long time better materials for catheters.

The development of an indwelling catheter that was retained in the bladder presented quite a challenge. And originally they were using catheters with balloons attached to them, balloons that were used from the small intestine of animals.

But it wasn’t until Doctor Foley in the 1930’s developed his catheter which he called The finally perfected catheter It was made from latex and it was retained in the bladder with a balloon. A balloon that in fact he designed as a haemostatic balloon when he was performing prostate surgery. And he would blow the balloon up in the prostate cavity in order to stop the bleeding.

But his then developed into an indwelling catheter. And this is the example of the Foley catheter which he designed and this was introduced in 1937. And it really has not in fact altered in design apart from the materials which are being used. He described the all-latex catheter, well of course latex is now, is not used as a pure bio material because you can get quite severe latex allergies.

This is an intermittent catheter and it is coated with a lubricious surface so that if you just pour a little water into the package, it wets the surface of the catheter and that makes it very slippery. And you just then can take the catheter, and this can be passed into the urethra and the bladder drained.

Are there different sorts of intermittent catheter?

There are but it just consists of a straight catheter in fact.

Would there be different sizes?

Yes, oh yes. There would be different sizes from quite narrow ones. The gauge of the catheter is measured by what we call the French gauge, that’s the circumference of the catheter in millimetres.

Is it possible to cause any damage passing the catheter?

Yes, yes. Passing a catheter in a male patient of course can cause problems because the male urethra is about 18 centimetres, whereas the female urethra is about 4 centimetres. And the male urethra is at risk when a catheter is passed because it can damage the surface and cause an abrasion of the lining.

But do most people manage it alright without any damage?

As long as they’ve been well trained how to perform intermittent self-catheterisation. That is the really important point. And continence advisors are well experienced at teaching people how to perform intermittent self-catheterisation.

Some women develop problems with bladder emptying following childbirth, and have difficulties emptying the bladder completely, and they can be taught intermittent self-catheterisation.

Patients who have neurological conditions too, multiple sclerosis for example, spinal injuries, many of these patients are performing intermittent self-catheterisation now.

Intermittent catheterisation is now considered to be the gold standard for emptying the bladder. it’s an interesting history here, because Everard Home in 1806 actually advocated intermittent catheterisation and during the 19th century men would carry their catheters around in their top hats and in their walking sticks.

And it went out of fashion for many years, until it was brought back by Lapides, an American urologist in 1972. He pointed out that intermittent self-catheterisation could be performed quite safely. And this completely transformed the care of young children with spina bifida. Many of those children were undergoing quite major surgery because of the problems they had with bladder emptying.

But nowadays they go to school with a catheter in their pocket and they just perform intermittent self-catheterisation. And they’re able to empty the bladder completely and they manage this without experiencing serious infections in most cases. That is rare.

The external catheter or condom catheter is useful because it avoids having to pass a catheter through the urethra. It is only applicable in males, but it is a condom which is rolled onto the penis and it has an adhesive surface to it which maintains it itself in position. So that is the condom fitted onto a penis and the end of the condom is drained into a leg bag.

Now this is of value in some elderly patients who are troubled with incontinence when they are in bed. But the problem is that in elderly men the penis retracts and the condom comes off. Or sometimes the condom can twist around and then it fails to drain and urine then builds up behind and washes the catheter, the condom off the penis. So there are problems with maintaining a condom catheter in position. If it can be maintained in position that’s very good.

But then there are other occasions when sometimes men develop an allergy to the adhesive on the condom, and they get a serious skin reaction. So there are always problems with every type of appliance that you do use. But it is useful in some cases.

Urinary catheterisation is undertaken to empty the bladder, to drain urine from the bladder. And this is a very ancient art. The history of urinary catheterisation makes a very fascinating story, going way back in papers that were written by the Chinese and Egyptians well into BC times.

And what is it exactly? You said why it’s used.

Yes, when the bladder fails to empty, it fills up and has to be drained. And if the bladder fails to empty, it gets very distended and painful. So urinary catheterisation is being undertaken to drain the bladder and, in the ancient times, they used reeds. They used leaves from the onion plant, Allium fistulosum, which has hollow leaves. A bronze catheter was found at Pompeii. And that was used by the surgeon there.

I’m tracing its history. They’ve used gold and silver and of course the great discovery was rubber. But it took them a long time to discover how to use rubber. And it was the French who discovered that you could mould rubber using ether, and then they’ve produced the first gum elastic catheter in about 1790. Of course, nowadays we’re using polymers and silicones for making catheters.

Perhaps you could summarise some of the different reasons why people might want to have a catheter?

Yes. One of the major problems, of course, is when somebody goes into retention of urine and are unable to empty their bladder. it’s a common emergency amongst older men when they develop an enlargement of the prostate and they cannot pass urine.

But there are other occasions when it’s not possible, for example people who suffer from spinal injuries. Their bladder is then paralysed and the bladder fills up and it cannot drain. Then, of course, that can lead to back pressure on the kidneys and serious complications follow.

Any neurological condition that affects the behaviour of the bladder, the physiology of the bladder, of course can affect micturition [urination]. Under those circumstances the bladder fails to empty and fails to empty completely. That’s when complications arise.

So people who suffer from spinal injuries, multiple sclerosis, strokes in older age, can develop problems with the bladder, and which needs to be drained.