dialysisaccesses

Hemodialysis Accesses
(with appropriate nursing interventions and patient teaching)

Permanent Hemodialysis Accesses
      Permanent hemodialysis accesses consist of either grafts or fistulas. Grafts are created when a tubular section of artificial material such as Gortex is surgically connected to an artery and a vein creating a shunting of arterial blood into the venous system. The artificial graft typically forms a loop beneath the skin. For dialysis, two needles are inserted into the graft; one toward the arterial flow of blood and one with the direction of the venous outpouring of blood. Before use, grafts are generally allowed a "maturing" period of about two weeks, but can be used immediately after insertion in some cases. The maturation period of a graft is to allow the body to form connective tissue onto the graft which helps keep the graft in place and aids in the clot formation after pulling out any needle which is inserted.
     Fistulas are the most desired hemodialysis access due to the reduced chance of infection and the longevity expected of such an access. Fistulas are created when an artery is surgically connected to a vein. The maturation process lasts on average about three months, and is to allow the vein to dilate from the presence of arterial pressure. This dilation is to allow for easier insertion of the needles typically used for dialysis; generally 15ga. Fistulas are the optimal hemodialysis access due to their being made of no foriegn materials. Fistulas, being all natural, heal themselves, do not foster the growth of bacteria, and aren't intrinsictly rejected by the body.
     Nursing care for grafts and fistulas are basically the same with the only primary difference being the angles of needle insertion; fistula = 20degrees / graft = 45degrees. Before needle insertion, cleansing of the site is crucial. Site preparation varies slightly depending upon facility protocol, but is generally accepted to be as follows: cleanse the site with anitmicrobial soap and scrub with isopropyl alcohol and/or a povidone/iodine solution such as "Betadine" in a circular motion from center of site outward. When alcohol is used, needle insertion is made immediately following alcohol scrub. When Betadine is used, the solution is allowed to completely dry on the skin before needle insertion. To prevent clotting of the graft or fistula, it is imperative that no blood pressures or needle sticks be performed on the limb in which the access is placed.
     Proper patient teaching helps prolong the lifespan of a permanent hemodialysis access. Patients should be instructed to: keep the site clean, try not to rest on the limb which hosts the access, not to apply severe stress to the affected limb by lifting heavy objects. Also, it's considered appropriate to instruct the patient what to do should they start bleeding from the access; i.e. hold direct pressure and seek medical attention.

Temporary/Semipermanent Hemodialysis Accesses
     Temporary or semipermanent hemodialysis accesses are venous catheters either inserted directly into a vein or tunneled beneath the skin then into a vein. These accesses are generally refered to by their trade names which commonly include Shiley, Quinton, Tesio, Hemosplit, or VasCath. True temporary catheters (Shileys,Quintons) are inserted by a physician directly into a large vein such as the internal jugular, subclavian, or femoral vein. These catheters are intended to remain in place for only a few days and typically no more than a couple of weeks. Directly inserted femoral hemodialysis catheters require the patient to remain in bed with no more than a 20-30 degree inclination. All other directly inserted catheters allow the patient more freedom of position, but are typically more difficult to place than the femoral catheters.
     Tunneled catheters (Tesios, Hemosplits, Vascaths) are intended to last a bit longer than non-tunneled catheters and are therefore sometimes referred to as semipermanent. These catheters, usually seen in the upper chest, are tunneled beneath the skin and reside within a large vein of the body with the tips often sitting just inside the atrium of the heart. Other sites for insertion of this catheter include the groin with the catheter tips resting within the vena cava or insertion into a lower abdominal quadrant with the catheter tips resting within the vena cava near the atrium.
     Nursing care for hemodialysis catheters is basically the same for tunneled and nontunneled. Nurses generally must obtain a physician order to use before using. The steps for using are: cleanse the port per protocol (soak with povidone/iodine solution or cleanse with sodium hypochlorite solution), aspirate 10cc blood/heparin from catheter, flush with 10cc normal saline, administer meds or draw necessary blood work, flush with 10cc normal saline, lock with heparin (either 5000U/cc or 1000U/cc depending on facility protocol) while having patient hold in a breath of air. Clamps are to remain clamped at all times when not in use to prevent air from entering blood stream or to prevent bleeding should cap become removed. To help ensure sterility the immediate staff and the patient must wear masks while accessing hemodialysis catheters. Hemodialysis catheter dressing changes are typically performed by dialysis staff or per facility protocol for such catheters. However, before following facility protocol, one must first be certain that the cleansing solution prescribed by the prtocol is not detrimental to the cathter, itself. Some hemodialysis catheters are degraded by iodine solutions or alcohol. Use of scissors around hemodialysis catheters is strictly forbidden.
     Patients with hemodialysis catheters, whether tunneled or nontunneled, are instructed not to get direct water onto the catheter site, not to allow undue tension on catheter which may cause dislodging of cath, and to be on alert for bleeding from insertion site. Patients are instructed should cath become dislodged or if cath site should start bleeding to hold direct pressure and seek medical attention. Patients are taught not to use scissors near catheters and to keep clamps locked at all times.

Other Hemodialysis Accesses
     External AV shunts were at one time quite common. These accesses were, as the name implies, an aterio-venous shunt similar to a graft but located outside the skin. Due to advances in dialysis accesses, the external AV shunt is rarely used any more and thus will not be discussed in this forum.