For a while now I have toyed with this topic. It seemed too complex and too involving at first. It then became something that I imagined my audience not to be interested in. That is until a former patient called me to ask whether the hospital he last saw me at is performing vascular access surgeries.

What is Vascular access?

To understand this, I will have to go back to the basics. Both for people that are dealing with kidney failure and for the general public. I have noted with much appreciation the mixed nature of my audience. I must therefore serve this dish in mentally delicious helpings.

There are two types of dialysis. One being peritoneal dialysis and the other being haemodialysis. For the sake of today’s topic, we will focus on haemodialysis which is the commonest in Kenya and thus we will refer to it as ‘dialysis.’

Dialysis involves ‘cleaning’ the blood for the patient through the use of an artificial kidney and returning it to the patient. As you may see from this simple definition, we need a mechanism to remove blood from the patient’s bloodstream and then return it after it has been ‘cleaned.’

You may suggest using the normal needles and cannulas we are used to in the accident and emergency department or even in general wards and that could be a wonderful suggestion. However, it would require innumerable needle pricks and tubes for us to get the blood. Further, we would have no way to return such a large amount of blood to the patient’s body. This, if nothing else, excludes that possibility.

Dialysis operates as a continuous process. We need to remove, clean and return the blood to the bloodstream of the patient all at the same time. This is why a dialysis machine is important. It comes armed with a pump and other great things to help us draw the blood, clean it and return it at the same time. It is a seamless process. some machines have one pump while others like the one below have three. Whether one or three the principle is the same.

The method that we use to get the blood to leave and return to the bloodstream and go to the artificial kidney for cleaning through various tubes, pushed by the pump in the machine is what we call a vascular or blood access. There are a few methods used for this and I will address them and how to take care of them in the coming weeks. Let us look at one of them today.

 Catheters

A catheter is a small flexible tube inserted into a body cavity. The most common type of a catheter is the urinary catheter. This is a tube that is put into the urinary bladder to remove urine when the person is not able to urinate normally.

A dialysis catheter is a small flexible tube introduced to the heart through a major vein to help in removing and returning blood during dialysis. Dialysis catheters must be able to remove and return blood at the same time. This is why they have two lumens inside.

               Acute catheters

These are short, temporary tubes inserted into one of the veins on the side of the neck. Sometimes they are called necklines. They are not to be used for more than 72hours because they can easily get clotted inside and get infected. Some even drop off if care is not taken to secure them in place. They are too dangerous and are only used in cases of emergencies.

               Chronic Catheters

These are very common in Kenya and I will pay more attention to them. These tubes are longer, and they get inserted through one of the larger veins in the lower part of the neck.

What to do with Catheters

In a proper set up, catheters should be inserted under the guidance of an Xray machine. This helps the doctor to see the blood vessel which he or she is targeting and see how far the catheter is advancing. This reduces the chances of dangerous accidents like severe bleeding.

It is however a widely accepted practice that an Xray is performed immediately after the insertion of one catheter. As the patient or relative, you need not worry about pain because the doctor will make sure you have some sort of anaesthesia. This is a medication given to make you not feel pain.

It is not given so that you completely fall asleep. It only takes away pain the areas that the doctor will touch during the insertion. Your role is to just lie flat or in whatever position you will be guided to. Doctors tunnel the catheters under the skin such that only the blue and red parts are visible outside. The rest is safely hidden away. this helps to support the catheter securely in place and also lessen chances of infections.

Whether acute or chronic, catheters are still prone to infections. The worst part is that the infection may be on the skin where the catheter end exits the body or inside the tubing itself of the catheter.

Various practices are encouraged to keep infections at bay. Top in the list is covering the exit site of the catheter with a dressing. There are many dressings which are available in the market. The unit I work in focuses on dressings that contain Chlorhexidine for patients that are not allergic to this antiseptic. These are changed every seven days.

You cannot swim while having a catheter. Neither can you use a bathtub for a soak. This is because you risk making the dressing wet and thereby introducing germs into the catheter something that we do not want.

In proper set ups, two nurses are involved in the connection and disconnection of a patient from the dialysis machine. This is to make sure that the nurse that touches the catheter does not touch the machine to reduce the risk of infection transmission.

Locally, nurses avoid touching the dialysis machine by using gauzes dedicated for touching the machine only. That way the fingers of the nurse do not touch the screen of the machine and then touch the catheter as well.

Every time the catheter is accessed, nurses use sterile dressing packs to make sure that there is no risk of introducing germs to the catheters. Even then, we try to minimise the times that a catheter is manipulated during dialysis. We can never be too safe with dialysis catheters.

Catheters run the risk of becoming clotted hence not being able to remove and return blood during dialysis. The nurses will always use a medicine to ‘lock’ the catheters to make sure that they cannot clot. This medicine is removed using a syringe before every dialysis session. Unfortunately, doing so leads to loss of blood leading to anaemia. It is therefore important for you as a patient to receive the medications prescribed to increase your blood level. Most of these medications are given while dialysis is ongoing. That eliminates the need for multiple needle pricks. Nurses simply inject the medicine into the tube that is returning blood to your body.

If you happen to visit the outpatient department of any hospital for other reasons, it is important that your catheter is not used to draw any blood sample. Should the dressing need changing, only have a kidney nurse do it. That is because it requires careful handling which other nurses may not be familiar with.

Sometimes, medications are prescribed to eradicate infections, and these are administered through the catheter at various timelines during the dialysis treatment. If you find yourself shivering during dialysis and you have a catheter, chances are, there is an infection going on. Kidney nurses are adept at picking this up and running a few blood tests to confirm the same before starting you on much needed antibiotics.

You may find that in some units, nurses take swabs of the skin around the catheter and send to the laboratory for further investigations. This is to check that there are no germs around the catheter exit site which might lead to problems later on. It is the old adage of prevention is better than cure.

These catheters are not meant to stay in place indefinitely. They run too many risks and if dialysis is to be continued for the rest of your life, it is vital that the catheter gets removed and we go to a permanent blood access method. One that will allow you to continue with your life without worrying about infections.

It is my sincere hope that this has helped you understand a thing or two about dialysis catheters.