Why does an indwelling catheter clog?

If a bladder catheter is left in place for a longer period of time, encrustations often form and block the urinary flow. The encrustations are results of salts and chemical processes of certain types of bacteria that are found in the so-called “biofilm” of the catheter lumen. The probability of bacteria occurring increases with the length of time the catheter is in place. The presence of bacteria in the urine (bacteriuria) is almost unavoidable in patients with permanent urinary diversion. That causes the risk of incrustations and subsequent blockages to increases. In the first 12 months blockages statistically occur in every third permanently catheterized patient.

Possible consequences of a catheter blockade

The catheter blockage causes urine to back up in the bladder. For paitents affected this is extremely painful, especially as the problem is usually only noticed when the bladder is already full. If the blockage cannot be relieved by flushing, the only solution used to be to change the catheter immediately. In most cases, however, qualified personnel are not available or the necessary material is not available. Abdominal catheters (“Cystofix”) must be changed by a doctor or at least under medical supervision. Therefore, in such cases, the patient is usually transported to an emergency room or outpatient clinic.

Therefore a lot of time often passes before the problem is resolved. In addition to the inconvenience for those affected, the delay can have very serious consequences: As the urine of permanently urinated patients is always contaminated with bacteria, the backlog can lead to blood poisoning and/or acute kidney failure. The situation is particularly critical for paraplegic or unconscious patients, as they are unable to notice or express the problem themselves. As a result, so-called “autonomic dysreflexia” can occur, a sharp rise in blood pressure which can lead to heart and brain strokes, cerebral haemorrhages and, in the worst case death.

How can I prevent this from happening?

A key factor in avoiding encrustations is sufficient dilution of the urine by drinking or parenteral/tube-supported fluid intake. The aim is to avoid a specific weight < 1015 g/l. In practice, the urine should appear as light and transparent as possible.

Good hygiene is important so that your bladder catheter is less likely to get blocked. For this reason, the outer part of urinal catheters in the natural urethra should be cleaned daily with soap and water. In the case of abdominal catheters, the insertion should be kept clean and the initially recommended dressing should be replaced regularly (at least every 2-3 days).

Closed drainage systems are generally recommended, whereby the urine bag should be equipped with a drip chamber with a flap valve and positioned below the bladder level. Horizontal positioning of patients with installed leg pouch systems should be avoided.

Regular external bladder flushing should only be carried out in exceptional cases, as it tends to promote infections and is usually unable to loosen incrustations. In our experience, it can occasionally be useful to remove sediment from the bladder by weekly flushing, especially in bedridden patients. All of this helps to ensure that a bladder catheter becomes blocked less frequently. However, flushing definitely does not provide reliable protection against catheter blockages.

The repeatedly described acidification of the urine by taking L-methionine has also not really proven itself to help patients who are frequently affected by catheter blockages.
The long-term use of antibiotics should be avoided at all costs to prevent the development of antibiotic resistance and serious side effects.

What can be done if a catheter is blocked?

A catheter blockage is an acute urological emergency that must be treated immediately to avoid complications such as pain and fever with subsequent blood poisoning and acute kidney failure.
If appropriate material is available, an attempt can be made to flush the catheter with sterile saline solution. There are products on the market with a suitable cone for connecting to the catheter and bellows for pressing in the solution. The use of a bladder syringe should be reserved for specialist personnel. Any manipulation with flexible wires is potentially life-threatening and must not be carried out under any circumstances!

If flushing is not possible, the catheter must be changed immediately. It should be noted that abdominal catheters in Germany may only be changed by a doctor or under a doctor’s supervision. In this case, immediate transportation to a doctor’s practice or emergency outpatient clinic is therefore necessary.

In future, our innovative CADO cleaning system could provide quick and safe help in such cases. With the CADO system, patients themselves or caring relatives or nursing staff in care homes can carry out catheter cleaning at the bedside. After removing the incrustation, the catheter can be used again until the scheduled routine change. However, only bladder catheters approved by CADO medical solutions may be cleaned.

Our system is currently still in the approval process for medical devices and is therefore not yet available on the market. In our video you can see the application in an exemplary case.

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[1] Patient information from the German Society of Urology (DGU) and the Professional Association of German Urologists (BDU) on catheter care and stoma care (as of 11/2020) via urologenportal .de
[2] Wilde, Mary H., James M. McMahon, Hugh F. Crean, and Judith Brasch. “Exploring Relationships of Catheter-Associated Urinary Tract Infection and Blockage in People with Long-Term Indwelling Urinary Catheters”. Journal of Clinical Nursing 26, no. 17-18 (September 2017): 2558-71(link to source)