Arteriovenous Native Fistula (AVF)
Usually created in the forearm by a side-toside, end-to-side, or end-to-end anastomosis between an artery and a vein. The fistula provides arterial blood flow thought the vein, essential to provide the rapid blood flow required by hemodialysis. Requires health blood vessels
Arteriovenous grafts (AVG)
A synthetic graft may be required for clients requiring arteriovenous (AV) access, but who do not have health blood vessels. Grafts are placed surgically and are self healing. Grafts are more likely that fistulas to clot off and become infected.
Thrills and Bruits
Thrills can be felt by palpating over the AV anastomosis. Bruits can be auscultated using a stethoscope. Arterial blood rushing into the vein creates the bruit and thrill
Protection of the Access Extremity
Blood pressures, IV insertion and venipuncture should not be performed on the affected extremity. This prevents infection and clotting.
Temporary Vascular Access VIA Central line (Quinaton, Permacath)
Subclavian, internal jugular and femoral veins can be used to provide quick, temporary vascular access. These central catheters must be double lumen and can be left in for several weeks. Temporary access can be used while waiting for permanent access to be created and to mature for usage.
AV Fistula Access Pros/Cons
Direct connection of artery and vein under the skin, best long-term, less risk, less complications, better blood flow, located in forarm or upper arm, needs 3-4 months to mature
- Augments BF
- Lasts many years
- Best vascular access
- Best perfusion
- Reduces infection rate
- Non aesthetic
- No indicator
- Time to mature
- Fail to develop
- Complications include aneurysm and stenosis
AV graft (permanent) Assess Pros/Cons
Connection between artery and vein is through a synthetic tube. Implanted by a surgeon under the skin. Takes 2-3 weeks to develop
- Use faster
- Use repeatedly
- Short life
- high probability of clotting
- High possibility of infection
Venous catheter (temporary)
Termpoary catheter (locally: quinton, permacath) for up to 3 weeks. If fistula fails. Neck9 jugular, chest (subclavian), leg (femoral, two chambers (in and out)
- No needles
- Emergency places easily, replaced and removed
- Narrow veins
- No swimming
- Elevated infection rates
- Increased clotting
- Complications: infection, low blood flow (clogging) catheter caps can fall off, air embolism, leaks, kinking
Purposes of Peritoneal and Hemo dialysis
The large natural surface area of the peritoneum makes it a good semipermeable membrane for performing dialysis. Removal of wastes
The dialyser provides dibers (cellulose of synthetic) as a semipermeable membrane. Blood passes through the lumen of thousands of these fibers and are bathed in dialysate. Removal of wastes.
Basic procedures of peritoneal dialysis and hemodialysis
Dialysis solution is instilled into the peritoneum for a prescribed period of time. Water and fluid are removed from the body into the dialysate because of the pressure gradient that is created by the addition of glucose to the dialysate. Three phases of the dialysis are inflow (fill), dwell (equilibration), and drain. One cycle of inflow, dwell, and drain is called an "exchange"
Excess fluid is removed by creating a pressure differential between the blood and the dialysate solution with a combination of positive pressure in the blood compartment or negative pressure in the dialysate compartment.
Contraindications of peritoneal and hemodialysis
Adhesions, perionitis (lots of scar tissue)
none, but hemodynamic changes may not be tolerated by all
Access method of peritoneal/hemodialysis
Obtained by inserting a catheter through the anterior abdominal wall. The tip of the catheter rests in the peritoneal cavity and has many perforations to allow fluid to flow in and out. Usually placed surgically.
Arteriovenous fistulas, arteriovenous grafts, temporary vascular access VIA central line
How often for peritoneal/hemodialysis
4 or more exhanges per day, possibly overnight
3 times per week for 3 or 4 hours
Assessment required for peritoneal/hemodialysis
- Exit site inspection
- Clarity of peritoneal effluent
- Teaching/learning assessment, can client perform these tasks?: cath care,assessment and dialysis exchanges
- Complications include: exit site infection, abdominal pain, hernias, lower back problems, bleeding, pulmonary complications, protein loss, carbohydrate and lipid abnormalities, peritonitis
- Fluid balance: weight, BP, peripheral edema, lung and heart sounds
- Vascular access condition
- Temperature and condition of skin
- Complications include: hypotension, muscle cramps (electrolytes shifting), loss of blood, hepatitis, sepsis, disequilibrium syndrome
Dialysis Equilibrium Syndrome
Hemodialysis: results from rapid changes in the composition of the extracellular fluid leading to shift of fluid into the brain, causing cerebral edema. Can result in seizures. Rare.