What to do if a Foley catheter is blocked?
First of all, you should make sure that it is indeed a blockage and not another problem, such as catheter displacement or kinking of the tubing. In this situation, relatives of the patient can simply move the tube slightly or knead it with their fingers. Sometimes this is enough for urine to start flowing into the urine bag again. However, such situations (tube kinking) are quite rare in practice.
In 99% of cases, it is indeed a blockage of the tube. What to do in this case? The answer is simple: replace the catheter with a new one.
You might ask me why you can’t flush the tube with furacilin or another solution. First, when you try to flush the device, you push mucus and other debris back into the bladder. What does this lead to? Chronic inflammation of the bladder. Second, the flushing attempt itself is extremely rarely successful. But even if you succeed, the restored urine flow will last at most 24 hours, and then everything repeats.
Why does the catheter become blocked?
Catheter blockage is a common problem encountered by both medical professionals and patients. Understanding the causes is key to timely prevention and proper management.
One of the main causes is the deposition of salts on the inner walls of the catheter. This often occurs when catheters are used under conditions of altered acid‑base balance or during prolonged indwelling. Mineral deposits (calcium and magnesium salts) gradually accumulate, forming a hard coating that narrows the lumen and obstructs fluid flow. This is especially relevant for long‑term urinary drainage.
In addition to mineral deposits, blood clots play a significant role. Blood in the catheter can arise from mucosal injury or vascular damage during insertion or use. With slow fluid flow or lack of regular flushing, clots form and can completely block the lumen. This not only impairs drainage but also increases the risk of infection, as clots provide a breeding ground for bacteria.
Another contributing factor is increased mucus production. In some cases, the mucous membranes react to the presence of a foreign body (the catheter) by producing more mucus.
Finally, exceeding the catheter’s service life is important. Each type of catheter has a recommended indwelling period, after which its properties change — the material becomes more brittle, and the inner walls accumulate more deposits. Using the device beyond its lifespan significantly increases the likelihood of blockage and complications. Therefore, regular replacement of the catheter according to the manufacturer’s instructions and the doctor’s recommendations is mandatory. I recommend changing the tube every 25 days. In Europe, the standard is to change it every 3 weeks.
How to flush a catheter if it is blocked?
As I already wrote, I consider flushing the tube useless and even harmful. But if you insist, here is how to do it.
If the catheter is blocked, first try to carefully restore its patency to avoid possible complications. Flushing must be performed with strict adherence to all recommendations and aseptic rules.
First, wash your hands thoroughly with soap or disinfect them to reduce the risk of infection. Then prepare the flushing solution. Normal saline (0.9% sodium chloride) is most commonly used. I do not recommend using other solutions, including the popular furacilin.
Flushing is performed with a syringe of 150–200 ml, depending on the type and size of the catheter. Disconnect the urine bag. Slowly and smoothly inject 100 ml of solution, without applying excessive pressure. If resistance is felt, do not increase the pressure — this could rupture the catheter. In such cases, it is better to stop and consult a doctor. After you have restored patency, reconnect the urine bag so that all the solution drains from the bladder.
If flushing is performed regularly, a new bottle of solution must be opened for each procedure; otherwise, it will no longer be sterile.
If the catheter remains blocked, there may be a thrombus or mechanical damage, and additional measures are required — ultrasound, thrombolytics, catheter replacement, or other interventions. Never try to clear severe blockages with force or without proper knowledge — this can lead to serious complications.