WHAT IS ARTERIOVENOUS FISTULA?
Arteriovenous fistula is generally defined as the formation of a connection between the arteries and veins and the pressured passage of blood from the arteries to the veins in this region. It can be congenital in places where the body should not be, or it can occur spontaneously after trauma.
In patients who need dialysis, it is aimed that the dialysis machine will clean the blood by performing the function of the kidney, since the kidney cannot perform its functions. However, vessels with high blood flow are needed for this procedure, which should be performed two or three times a week depending on the patient’s condition. The arteries are suitable for this flow, but since the pressure is high, it forces the device to work and the vascular damage that may occur in the arteries can lead to loss of limb and bleeding. For this reason, it is aimed to provide sufficient expansion and flow for the tongue in the vein by suturing the arteries and veins in the forearm, arm, and foot with local anesthesia in order to ensure the formation of veins that are easy to access, cannot bleed and have sufficient blood flow, so that effective and short-term dialysis is aimed. The important thing in the fistula to be created is to be able to provide sufficient blood flow for dialysis and to provide sufficient blood flow. If it cannot create enough flow, it will not allow the patient to receive dialysis and will not work in a short time. Even if the AV fistula is larger than necessary, it may cause complications such as heart failure, swelling of the arm and deterioration of nutrition in the patient, if it allows excessive blood flow.
When we touch the fistule, which we call thrill, with the hand, a humming simultaneous heartbeat occurs. Most of the time, patients can understand whether the fistula is working or not, thanks to this hum. In patients with arteriovenous fistula, in long-term use, this humming sensation, which is usually accompanied by arteriovenous fistula, becomes a co-existing finding.
Arteriovenous fistula can be opened from the ends, primarily to the wrist region, the inner parts of the elbow and the inguinal region. Especially in hemodialysis patients, it is mostly preferred to open it on the wrist area. Before arteriovenous fistula surgery, the compatibility of the vascular structure for the catheter opening should be checked with Doppler imaging.
Arteriovenous fistula operation is usually performed under local anesthesia. While making a choice, the arm that the person does not use is usually worked on. In other words, the right hand is preferred for left-handed patients, and the left hand is preferred for right-handed patients. The artery and the closest vein around it are detected through small incisions.
After the arteriovenous fistula operation, the fistula is not used immediately. It is waited for the desired vein width to be reached. In an average of a few weeks, the vessel reaches the desired width and a sufficient level of blood pressure and blood flow velocity is achieved for the hemodialysis procedure to be applied. The process of getting used to the fistula of this vessel is also called the maturation process. The fistula, which starts to work properly after a few weeks after the operation, provides use for years without any problems.
Catheter insertion
The catheter is a special tool made of polyurethane materials and is compatible with body tissue. They have the shape of a tube or cannula. Catheter type is used in many ways in the healthcare field.
Intravenous treatments with catheters, special treatment applications, drug administration, etc. Applications are made. A central venous catheter (CVC) is a thin, flexible tube (catheter) inserted into a large vein above the heart. It can be inserted through a vein in the neck, chest, or arm. It is also called the central venous line or the central line. Depending on the type of catheter, it may be left in place for weeks, months, or years. Central venous catheters require special care. They may need regular cleaning or sterile dressing changes. CVCs need to be washed regularly with a special sterile solution to prevent them from clogging when not in use. For this, the vein is entered into the vein under the neck or collarbone and it is useful in the current continuous patient follow-up. The use of this type of catheter is also seen in patients hospitalized in the intensive care unit. A central venous catheter is also required for applications such as plasmapheresis and dialysis for individuals with blood or kidney-related diseases. In addition, the drugs that are planned to be sent to patients who cannot open veins in the wrist, arm and foot are sent quickly via this route.
Hemodialysis Catheters: These catheters, which are developed for the patient to receive effective dialysis, can be safely placed in large vessels under ultrasound guidance. Two types are available.
Temporary catheters; They are catheters that meet the need for dialysis for approximately 3-4 weeks in patients who need short-term dialysis in the acute period. If it stays for a long time, it should be replaced because there is a risk of infection.
Permanent Catheters: It is our preferred treatment method if the AV fistula cannot be opened due to the patient’s vascular structure. With good care, the patient’s dialysis needs can be met for about 1 year without any complications. With local anesthesia, it can be inserted through the neck or under the collarbone with a needle, and can be safely placed under fluoroscopy.
Another method in catheter application is Port Catheters. It is a method used in cancer patients. Since the chemotherapy drugs used are of high density and may cause damage and obstruction in small vessels, it is aimed to administer the drug to the large vessels by inserting a port catheter under local anesthesia, with the recommendation of oncology doctors, so that the risk of clot and obstruction is less and that sufficient and effective chemotherapy drugs are taken. After the patient’s need for chemotherapy is over, this catheter, which is placed under the skin, is easily removed with local anesthesia.