Health & Disease Info
All You Wanted to Know About ... Vascular Access Devices

What are Vascular Access Devices?
There are many reasons why a person may require a vascular access device including the need for long term antibiotics, chemotherapy, nutritional therapy, other frequent medication requirements, or the cleansing of the blood in kidney failure. These needs, however, can be grouped into two basic categories. One where the doctor needs to give you something to treat a problem and one where your blood is taken out of your body, processed, and then returned. Furthermore, the needs may be of a temporary nature or more permanent. Finally, the frequency of the access needs will vary from patient to patient and problem to problem. All of these considerations have to be weighed in evaluating and recommending the specific need.

What are the Options?
Obviously, the first option would be to refuse access. Beyond this we need to consider specific needs.

1. Very short term needs can usually be met by simple intravenous lines (IV lines). If you run out of usable veins or your veins are very deep so that IV lines become impractical then longer access can be obtained by placing Central Venous Lines (so called CVP's). These types of lines are used during hospital stays and are usually removed when leaving the acute care setting.

2. Long term, frequent access needs. When a longer term problem exists and therapy can be administered as an out-patient, there are several options available. Frequent access usually means at least daily, if not several times per day. These options, therefore, offer ease of "connection" for therapy with some safeguard against infection.

A. The PIC Catheter - This is a catheter placed through the big vein at your elbow which travels up the arm, across the shoulder and into the chest vein (the superior vena cava or SVC) so that it lies just outside the heart. This is the simplest of the long term accesses, but has the shortest use expectancy. This can be placed in your arm by specially-trained RNs on an outpatient basis.

B. The Groshong Catheter - This catheter is placed thru a big vein in your neck (the internal jugular vein or Ij) or under your collar bone (the subclavian vein or SW) by a physician. They also lie just outside the heart in the SVC. These catheters are usually placed percutaneously (using a needle and guide wire), but may need to be placed by cutting down on the vein and inserting the catheter under direct vision. Once placed, these catheters can be brought out through the skin in any convenient area on the chest to provide easy access to the vascular system. The catheter will exit the skin and have its access connection some distance from the skin. There is a Dacron cuff on the catheter just below the skin. Scar tissue will grow into this cuff and perform two vital functions: One, it anchors the catheter so that it cannot be easily pulled out; and Two, it forms a barrier to infection so that the bacteria on your skin cannot climb down along the catheter tract to cause a blood infection. It is this property that allows the catheter to be used for long term therapy. These catheters are available in both single and double lumen configurations and will be chosen according to your particular problem. There are other variations of this catheter, but all function in about the same way.

C. The Quinton Dialysis Catheter - This catheter is used for temporary access in kidney failure patients. It may be used either as definitive access in acute renal failure (which is usually a temporary condition) or as temporary access while a more definitive access is being obtained. It is placed by making a small incision at the base of your neck and finding the big vein under the larger muscle in your neck. The catheter is placed into this vein and then tunnelled under the skin to exit on the shoulder just under the collar bone. Your blood will be taken from one side of the catheter and passed thru the dialysis machine to cleanse it. It will then be passed back in thru the other side of the catheter returning it to your body. This catheter can be used for up to several months if needed to supply dialysis support. Its larger size permits faster flow rates to allow a good dialysis in a reasonable length of time. It is usually not used for permanent access, however, because as with all catheters which exit from the skin, there is an increasing incidence of infection as time goes on.

3. Long term, infrequent access needs. When long term access is needed, but the need to use it is less frequent (varying from days to weeks) the same types of catheters can be used as above described (except for Quinton catheter), but they can be attached to a port which is placed under the skin. Access is obtained by placing a special needle thru the skin and silicone diaphragm of the port into the well which is connected to the catheter. Blood can be withdrawn for testing and medications can be administered as needed.

The ports are usually placed under the skin of the chest, but can also be placed on the arm for the peripheral catheters. Ports minimize the chance of infection and are more convenient for those requiring infrequent use because they are entirely below the skin and are not exposed to outside bacteria except thru needle puncture. Therefore, skin preparation before needle puncture is of importance.

4. Long term, permanent access for dialysis patients - This group of access procedures is almost endless and is limited only by the imagination of the surgeon when presented with even the most unusual access needs and restrictions. There are, however, some very basic groups into which these procedures fall.

A. Peritoneal Dialysis - It may seem odd to include this as a section on vascular access, but when viewed in terms of what can be accomplished transperitoneally, it becomes obvious that even though we aren't going directly into the blood stream by this route, we certainly have access to it. Not only can a kidney failure patient be dialyzed by this method, but a variety of medications can be delivered by this route. The standard catheter used is a pig tailed Tenckhoff catheter. We usually insert this under local anesthesia with some sedation by the anesthesiologist. It can be done as an outpatient, but many times the patients are admitted for training in the use of the catheter.

A small incision is made just below the umbilicus (belly button) and the catheter is placed into the depths of the pelvis just in front of the rectum. This is the most dependent position and works best for instilling the fluid and for removing it. The catheter has two cuffs as barriers to infection. One lies just outside the inner abdominal envelope. The other lies in the fat under the skin. The tube exits from the skin to one side or the other of the main incision. These also anchor the tube so that is cannot be accidentally pulled out. A Nephrologist (kidney specialist) would arrange for thorough training in the use of this access device.

There are a few complications associated with the insertion procedure. Whenever the skin is cut and especially when a foreign body is placed, there is a chance of bleeding and/or infection. There is a small chance that the bowel or its circulation may be damaged. Poor healing can occur. Leakage of dialysis fluid and hernia can occur. These are all relatively unusual problems.

B. Autogenous (your own tissue) Fistulas - Whenever hemodialysis is planned, the first choice of access is the Cimino fistula. This is a connection of the big vein in the thumb side of the wrist with the artery on that same side (where the nurse usually takes your pulse). It is done thru a small incision over the radial artery which is made under local anesthesia. The artery and vein are mobilized and brought together. The distal vein is tied off and the end of the vein is sewn into the side of the artery. This allows arterial blood to flow into the vein. Since the artery has more pressure in it, the vein will dilate and become large enough and thick walled enough for the dialysis nurse to place the needles into it to effect dialysis without causing the vein to burst. This process of maturation requires 6 to 8 weeks to occur. If dialysis is needed before this, then some form of temporary access will need to be obtained. The biggest reason this fistula cannot be created in some cases is the lack of satisfactory vein due to either small size or previous use.

When a wrist fistula cannot be done, we feel it is still preferable to use the patient's own tissue if possible. There are two veins in the upper arm which can be used to create an autogenous fistula. The cephalic vein runs on the front of the arm over the biceps muscle. The basilic vein runs on the inner side of the arm and is too deep to use it. If the cephalic vein is large and superficial, it can be sewn to the brachial artery directly to create the fistula.

Unfortunately, this is not often the case. The basilic vein, if it is large enough to use, can be completely removed from the bed in which it lies and tunnelled under the skin in a curved path before sewing it to the brachial artery as in figure B. this a very reliable fistula and has few long term problems It also takes six to eight weeks to mature.

The complications of this operation are several although they are usually not serious. Again, bleeding and infection are ever present problems with any surgical procedure. There are a number of nerves present around the arteries and veins we are using. These are always identified, but may be damaged leading to numbness or a burning sensation in most cases. Rarely a motor problem can be encountered. The most common complication is a "steal phenomenon". Usually all the blood entering the arm is delivered to the forearm and hand. After creating a fistula some of that blood will go thru the graft rather than down the arm. This is usually a temporary problem which is relieved as the artery carries more blood and the forearm and hand vessels dilate to accept more blood, but occasionally this does not happen and the symptoms of pain, burning, and numbness can be experienced. If symptoms are not relieved by about a month, then banding of the fistula to make it smaller or some similar modification of the fistula will have to be done. Aneurysmal degeneration (ballooning out) of the fistula can occur from repeated needle punctures in the same area. If this occurs, the aneurysm must be resected and replaced with a graft.

C. Prosthetic Fistulas - Prosthetic grafts of many types have been used in the past when autogenous tissue is not available. Today the most common graft is made of Teflon material and is called Gortex. These grafts can be placed just about anywhere that an artery and vein can be connected. They have been placed in the forearm, the upper arm, across the chest, and even in the leg. Most commonly they are placed in the upper arm sewing them to the brachial artery just above the elbow crease and to the axillary vein up under the arm. This graft can be used in about two weeks.

The same complications listed above can occur here also. In addition, because this is an artificial graft, it can become infected by needle punctures whereas the autogenous fistulas will not. A unique complication can occur at the site where the graft is sewn into the axillary vein. The blood jets out of the fistula causing turbulence in the vein. This can cause a scar tissue response inside the vein and result in a narrowing of the anastomosis. If this occurs, revision is needed. Finally, these artificial grafts will occasionally clot requiring a thrombectomy (removal of the blood clot using a balloon catheter). The cause for the clotting is many times not found, but often associated with narrowing at the venous anastomosis. Grafts may also clot when dehydration occurs.

We hope this information will be helpful in understanding what can be done for you to answer the need for vascular access and what the procedure to place the device is like. We have included a short discussion of complications of each technique as well. These are the most commonly seen problems and should not be considered as an all inclusive list.