HEMODIALYSIS

• Shunting of blood from the body to the dialyzer in which diffusion, osmosis, and ultrafiltration processes occurs separating fluid and particles from the blood.

• Uses of hemodialysis– Cleanses the blood of accumulated

waste products– Removes the by-products of protein

metabolism, such as urea, creatinine, and uric acid

– Removes excessive fluids–Maintains or restores the body’s buffer

system–Maintains or restores electrolyte

levels

• Principles of hemodialysis– The semipermeable membrane is made of a thin,

porous cellophane– The pore size of the membrane allows small

particles to pass through, such as urea, creatinine, uric acid, and water molecules

– Proteins, bacteria, and blood cells are too large to pass through the membrane

– The client’s blood flows into dialyzer; the movement of substances occurs from the blood to the dialysate

– Diffusion: The movement of particles from an area of greater concentration to one of a lesser concentration

– Osmosis: The movement of fluids across a semipermeable membrane from an area of lesser concentration of particles to an area of greater concentration of particles

– Ultrafiltration: The movement of fluid across a semipermeable membrane as a result of an artificially created pressure gradient

• Implementation– vital signs– laboratory values before, during, and after

dialysis– Assess the client for fluid overload prior to the

procedure– Assess patency of the blood access device– Weigh the client before and after the procedure to

determine fluid loss– Hold antihypertensives and other medications

that can affect the BP prior to the procedure, as prescribed

– Hold medications that could be dialyzed off, such as water-soluble vitamins and certain antibiotics

– Monitor for shock and hypovolemia during the procedure

– Provide adequate nutrition (client may eat prior to the procedure)

– A rapid change in the composition of the extracellular fluid (ECF) occurs during hemodialysis

– Solutes are removed from the blood faster than from the cerebrospinal fluid (CSF) and brain; fluid is pulled into the brain, causing cerebral edema

COMPLICATIONS OF HEMODIALYSIS:

Disequilibrium syndrome

• Assessment– Nausea– Vomiting– Headache– Hypertension– Restlessness and agitation– Confusion– Seizures

• Implementation– Reduce environmental stimuli– Prepare to dialyze the client for a shorter

period at reduced blood flow rates to prevent occurrence

Dialysis encephalopathy

• aluminum toxicity - aluminum in the H2O sources used in the dialysate, and the ingestion of aluminum-containing antacids (phosphate binders)

• Assessment– Progressive neurological impairment– Mental cloudiness– Speech disturbances– Dementia– Muscle incoordination– Bone pain– Seizures

• Implementation– Monitor for signs of disequilibrium syndrome– Notify the physician if signs of disequilibrium

syndrome occur– Administer aluminum-chelating agents as

prescribed so that the aluminum is freed up and dialyzed from the body

• Subclavian vein catheter– Is usually filled with heparin and

capped to maintain patency between dialysis treatments

– The catheter should not be uncapped– The catheter may be left in place for up to

6 weeks if complications do not occur

• Implementation– Assess insertion site for hematoma,

bleeding, dislodging, and infection– Do not use these catheters for any reason

other than dialysis– Maintain an occlusive dressing

• Femoral vein catheter– The client should not sit up more

than 45 degrees or lean forward, or the catheter may kink and occlude

– Assess extremity for circulation, temperature, and pulses

– Prevent pulling or disconnecting of the catheter when giving care

– Use an IV control pump with microdrip tubing if a heparin infusion is prescribed

External arteriovenous shunt (AV shunt)

– surgical insertion of two Silastic cannulas into an artery and a vein in the forearm or leg, to form an external blood path

– U shape; blood flows artery shunt vein– A tube leading to the membrane

compartment of the dialyzer is connected to the arterial cannula

– Blood fills the membrane compartment and flows back to the client by way of a tube connected to the venous cannula

– When dialysis is complete, the cannulas are clamped and reattached to form their U shape

• Advantages– Can be used

immediately following creation

– No venipuncture is necessary for dialysis

• Disadvantages– External danger of

disconnecting or dislodging

– Risk of hemorrhage, infection, or clotting

– Skin erosion around the catheter site can occur

• Implementation– Avoid wetting the shunt– A dressing is completely wrapped around the

shunt and kept dry and intact– Cannula clamps need to be available at the

client’s bedside– Do not take a blood pressure, draw blood,

place an IV, or administer injections in the shunt extremity

– patent if it is warm to touch– Auscultate and palpate for a bruit, although a

bruit may not be heard and is not always felt with the shunt

– Notify the physician immediately if signs of clotting, hemorrhage, or infection occur

• Signs of clotting– Fold back the dressing, check for

Fibrin-white flecks noted in the tubing

– The absence of a previously heard bruit

– Coolness of the tubing or extremity– Client complaints of a tingling

sensation

Internal arteriovenous fistula (AV fistula)

– chronic dialysis clients– Created surgically by anastomosis of an

artery in the arm to a vein; this creates an opening or fistula between a large artery and a large vein

– The flow of arterial blood into the venous system causes the veins to become engorged (matured or developed)

– Maturity takes about 1 to 2 weeks and is required before the fistula can be used, so that the engorged vein can be punctured with a large-bore needle for the dialysis procedure

– Subclavian or femoral catheters, peritoneal dialysis, or an external AV shunt can be used for dialysis while the fistula is maturing or developing

• Advantages– Since the fistula is internal- less

danger of clotting and bleeding

– used indefinitely– Decreased incidence of

infection– No external dressing is required– freedom of movement

• Disadvantages– Cannot be used immediately

after insertion– Needle insertions are required

for dialysis– Infiltration of the needles during

dialysis can occur and cause hematomas

– An aneurysm can form in the fistula

– Arterial steal syndrome can develop (too much blood is diverted to the vein, and arterial perfusion to the hand is compromised)

– CHF can occur from the increased blood flow in the venous system

Internal arteriovenous graft (AV graft)

– chronic dialysis clients who do not have adequate blood vessels for the creation of a fistula

– Gore-Tex or a bovine (cow) carotid artery is used to create an artificial vein for blood flow

– The procedure involves the anastomosis of the graft of the artery, a tunneling under the skin, and anastomosis to a vein

– The graft can be used 2 weeks after insertion

– Complications of the graft include clotting, aneurysms, and infection

• Advantages– Since the graft is internal, there is less danger of

clotting and bleeding– The graft can be used indefinitely– Decreased incidence of infection– No external dressing is required– Allows freedom of movement

• Disadvantages– Cannot be used immediately after insertion– Needle insertions are required for dialysis– Infiltration of the needles during dialysis can

occur and cause hematomas– An aneurysm can form in the graft– Arterial steal syndrome can develop (too much

blood is diverted to the vein, and arterial perfusion to the hand is compromised)

– CHF can occur from the increased blood flow in the venous system

• Implementation for AV fistula and AV graft– Do not measure a blood pressure, draw blood, place an

IV, or administer injections in the fistula or graft extremity

– Monitor for clotting• Complaints of tingling or discomfort in the extremity• Inability to palpate a thrill or auscultate a bruit over

the fistula or graft– Monitor for arterial steal syndrome

• Palpate pulses below the fistula or graft, and monitor for hand swelling as an indication of ischemia

• Note temperature and capillary refill of the extremity– Monitor for infection– Monitor lung and heart sounds for signs of CHF– Notify the physician immediately if signs of clotting,

infection, or arterial steal syndrome occur

PERITONEAL DIALYSIS • The peritoneum is the dialyzing membrane

(semipermeable membrane) and substitutes for kidney function during kidney failure

• Works on the principles of diffusion and osmosis, and the dialysis occurs via the transfer of fluid and solute from the bloodstream through the peritoneum

• large and porous, allowing solutes and fluid to move via an osmotic gradient from an area of higher concentration in the body at an area of lower concentration in the dialyzing fluid

• The peritoneal cavity is rich in capillaries; therefore, it provides a ready access to blood supply

• Contraindications to peritoneal dialysis– Peritonitis– Recent abdominal surgery– Abdominal adhesions– Impending renal transplant

• Dialysate-sterile– The higher the glucose concentration, the

greater the amount of fluid removed during an exchange

– Heparin- prevent clotting of the catheter– Antibiotics: Prophylactic - prevent peritonitis– Insulin: - to control blood sugar most esp for pt with

DM

ACCESS FOR PERITONEAL DIALYSIS

• siliconized rubber catheter• 3 to 5 cm below the umbilicus -

avascular and has less fascial resistance

• The catheters are tunneled under the skin to stabilize the catheter and reduce the risk of infection

• 1 to 2 weeks - ingrowth of fibroblasts and blood vessels into the cuffs of the catheter, which fix the catheter in place and provide an extra barrier against dialysate leakage and bacterial invasion

Peritoneal dialysis infusion

– One infusion (inflow), dwell,and outflow =one exchange

– open system - risk of infection– Inflow: 1 to 2 liters of dialysate 10 to 20

minutes– Dwell time: The amount of time in the cavity;

prescribed by the physician usually about 20-30 mins

– Outflow: Fluid drains out of body by gravity into the drainage bag

• Implementation before treatment– Monitor vital signs– Obtain weight– Have the client void, if possible– Assess electrolyte and glucose levels

• Implementation during treatment– Monitor for signs of infection, – Monitor for respiratory distress, pain, or

discomfort– Monitor for signs of pulmonary edema– Monitor for hypotension and hypertension– Monitor for malaise, nausea, vomiting– Assess the catheter site dressing for wetness

or bleeding– Do not allow dwell time to extend

hyperglycemia– Turn the client from side to side or have the

client sit upright if the flow is slow to start– Monitor outflow, which should be a continuous

stream after the clamp is opened– Monitor outflow for color and clarity, I & O

accurately– If outflow is less than inflow, the difference is

equal to the amount absorbed or retained by the client during dialysis and should be counted as intake

• Implementation after the treatment

– Clean the port and insertion site with antiseptic solution and sterile cap is applied.

– Pt should WOF s/sx of peritonitis (most common complication which includes• Fever and chills• Diffuse abdominal pain• Board like abdomen• Cloudy dialysate

Other approaches to Peritoneal Dialysis

• Continous Cyclic Peritoneal Dialysis (CCPD)– Use of a special machine called cycler used to instil and

drain the dialysate from the pt.– The machine has a series of automatic on/off switches

that regulate the instillation and draining of the dialysate in and out of the pt’s abdomen.

– Therefore it allows pt to maintain sound sleep at night.

• Continuous Ambulatory Peritoneal Dialysis (CAPD)– Same principle with regular PD but the dwell time is

approximately longer (4-6hrs) with 4-5 exchanges/day in a week.

– Does not require special machine

RENAL TRANSPLANTATION• Permanently solves the problem of ESRD pt.• Donor Selection– Living donor- twins less possibility of rejection– Non-living donor or cadaveric donors– Histocomaptibility by blood (ABO and Rh) and human

leukocyte antigen (HLA) profile.– Must be of legal age, mentally healthy and free from

systemic diseases– Harvested kidneys is viable for transplantation within 72

hrs. The earlier the transplantation the better the outcomes.

– Methods of preservation includes washing off formed blood elements, perfusing a heparinised electrolyte solution at 2OC-4OC, use of pulsatile flow pump and oxygenator.

• The transplant surgeon will harvest the kidney, renal artery, renal vein, and ureter.

• Recipient selection– Age– Must have an advanced and irreversible renal

damage– Must be free from systemic illness– Compatible profile with the donor

donor nephrectomy is performed, surgery begins an hour or two before the recipient’s surgery is started.

The donor artery is anastomosed to the recipient’s internal iliac or external iliac artery. The donor vein is anastomosed to the recipient’s external iliac vein, and the donors ureter is implanted directly to the bladder.

When the anastomoses are complete, the clamps are released, and blood flow to the kidney is reestablished. The kidney should become firm and pink. Urine may begin to flow from the ureter immediately. Mannitol or furosemide may be administered to promote diuresis.

Post Op Care- Donor

• Postoperative care is similar to that following conventional or laparoscopic nephrectomy

• Close monitoring of renal function to assess for impairment and of the hematocrit to assess for bleeding is essential.

• The creatinine should be less than 1.4 mg/dl• hematocrit should not fall more than 3 to 6 points

from pre-op value• Pain alleviating measures must be implemented to

maintain comfort.– Conventional nephrectomy- discharged in 4 to 7

days and can usually return to work in 6 to 8 weeks.

– Laparoscopic nephrectomy- discharged in 2 to 4 days and can return to work in 4 to 6 weeks.

Post Op Care- Recipient1. Priority is maintenance of fluid and

electrolyte balance. Very large volumes (UO=1L/hr) of urine may be produced soon after the blood supply to the transplanted kidney is reestablished. This diuresis is due toa. The new kidney’s ability to filter BUN, which

acts as an osmotic diuretic,b. The abundance of fluids administered during

the operation,c. Initial renal tubular dysfunction, which inhibits

the kidney from concentrating urine normally.

2. Organ Rejection• Hyperacute (antibody-mediated, humoral)

rejection occurs minutes to hours after transplantation.

• Acute rejection occurs days to months after transplantation. This type of rejection is mediated by the recipient’s T cytotoxic lymphocytes. Condition is reversible with additional immunosuppressive therapy

• Chronic rejection occurs over months or years and is irreversible. The kidney is infiltrated with large numbers of T and B cells characteristic of an ongoing low-grade immune-mediated injury.

• Signs of acute rejection– creatinine and BUN– Chills and fever– Weight gain (2-3 lbs in

24 hrs)– urine output– BP– Pain and tenderness

over the transplanted kidney

– General malaise– Edema

• Immunosuppressant Therapy– Azathioiprine (Imuran)- inhits DNA/RNA

synthesis thereby suppressing antibody formation.

– Cyclophosphamide (Cytoxan)- same as Azathioiprine plus destroys circulating lymphocytes.

– Cyclosporine (Sandimmune)- inhibits antibody production that leads to graft rejection. Major SE is nephrotoxicity.

– Steroids (Prednisone) suppresses phagocytic activity of macrophage.