class %2318 - dialysis pp (2

FOCUS ON

DIALYSIS

2Dialysis Movement of fluid/molecules across a semipermeable membrane from

one compartment to another

Used to correct fluid/electrolyte imbalances and to remove waste

products in renal failure

Treat drug overdoses

Two methods of dialysis available

Peritoneal dialysis (PD)

Hemodialysis (HD)

Clinically, dialysis is a technique by which substances move from the

blood through a semipermeable membrane and into a dialysis solution

(dialysate).

In PD, the peritoneal membrane acts as the semipermeable membrane.

In HD, an artificial membrane (usually made of cellulose-based or

synthetic materials) is used as the semipermeable membrane and is in

contact with the patients blood.

3Dialysis Initiated when GFR (or creatinine clearance)

4Osmosis and Diffusion Across

Semipermeable Membrane

Copyright 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc.

Ultrafiltration-

Water & fluid

removal

Results when an

osmotic gradient

occurs across the

membrane

5Peritoneal Dialysis

Peritoneal access is obtained by inserting a

catheter through the anterior wall.

Technique for catheter placement varies.

Usually done via surgery

In the United States, approximately 12% of

patients receiving dialysis treatments are on PD.

Preparation of the patient for catheter insertion

includes emptying the bladder and bowel,

weighing the patient, and obtaining a signed

consent form.

6Tenckhoff Catheter

Fig. 47-5. Peritoneal dialysis showing peritoneal catheter inserted into peritoneal cavity.



After catheter is inserted, skin is cleaned w/

antiseptic solution & sterile dressing

applied.

Connected to sterile tubing system

Secured to abdomen w/ tape

Catheter irrigated immediately


Waiting period of 7 to 14 days preferable

2 - 4 weeks after implantation,

exit site should be clean, dry, & free of

redness/tenderness.

Once site has healed, patient may

shower & pat dry.

Some patients just wash with soap and water and go

without a dressing; others require daily dressing changes.

However, teach all patients to examine their catheter site

for signs of infection.

Showering is preferred, as the exit site should not be

submerged in bath water.

9Peritoneal Catheter Exit Site

Fig. 47-6. Peritoneal catheter exit site.


10

Peritoneal Dialysis

Dialysis Solutions and Cycles

Available in 1- or 2-L plastic bags with glucose

concentrations of 1.5%, 2.5%, and 4.25%

Electrolyte composition similar to plasma

Solution warmed to body temperature

Dialysis solutions vary, and the choice of exchange

volume is primarily determined by the size of the

peritoneal cavity. A larger person may tolerate a 3-liter

exchange volume without any difficulty, whereas an

average-size person usually tolerates a 2-liter exchange.

Ultrafiltration (fluid removal) during PD depends on

osmotic forces, with glucose being the most effective

osmotic agent currently available.

11

Peritoneal Dialysis


Three phases of PD cycle

Inflow (fill)

Dwell (equilibration)

Drain

1 Cycle = Exchange

12

Peritoneal Dialysis


Inflow

Prescribed amount of solution infused

through established catheter over about

10 minutes

After solution infused, inflow clamp closed

to prevent air from entering tubing

The flow rate may be decreased if the

patient has pain.

13

Peritoneal Dialysis


Dwell

Diffusion and osmosis occur between

patients blood and peritoneal cavity.

Duration of time varies, depending on the

method.

20 30 minutes to 8 hours or more

14

Peritoneal Dialysis


Drain

15 to 30 minutes

May be facilitated by gently

massaging abdomen or changing position

The cycle starts again with the infusion of another 2 L of solution.

For manual PD, a period of about 30 to 50 minutes is required to

complete an exchange

15

Peritoneal Dialysis

Systems

Automated peritoneal dialysis

(APD)

Cycler delivers the dialysate.

Times and controls fill, dwell, and drain.

APD is the most popular form of PD, as it allows patients to

accomplish dialysis while they sleep. The machine cycles four

or more exchanges per night with 1 to 2 hours per exchange.

{See next slide for APD figure.}

CAPD: Exchanges are carried out manually by exchanging

1.5 to 3 L of peritoneal dialysate at least 4 times daily, with

dwell times averaging 4 hours. For example, one schedule

starts exchanges at 7 AM, 12 noon, 5 PM, and 10 PM.

16

Automated Peritoneal Dialysis


17

Peritoneal Dialysis

Complications Exit site infection

Peritonitis

Hernias

Lower back problems

Bleeding

Pulmonary complications

Protein loss

Infection of the peritoneal catheter exit site is most commonly caused

by Staphylococcus aureus or S. epidermidis (from skin flora).

Most frequently, peritonitis occurs because of improper technique in

making or breaking connections for exchanges.

Because of increased intraabdominal pressure secondary to dialysate

infusion, hernias can develop in predisposed individuals such as

multiparous women and older men.

18

Peritoneal Dialysis

Effectiveness

Short training program

Independence

Ease of traveling

Fewer dietary restrictions

Greater mobility than with HD

Learning the self-management skills required to do peritoneal dialysis

is usually accomplished in a 3- to 7-day training program.

Mortality rates are about equal between in-center hemodialysis

patients and peritoneal dialysis patients for the first few years.

However, after about 2 years, mortality rates for patients receiving PD

are higher, especially for the elderly with diabetes and patients with a

prior history of cardiovascular disease.

19

Hemodialysis

Vascular Access Sites

Obtaining vascular access is one of the most difficult problems.

Types of access include

Arteriovenous fistulae and grafts

Temporary vascular access

AVF have the best overall patency rates and the least number

of complications (e.g., thrombosis, infection) of all vascular

accesses.

In some situations when immediate vascular access is

required, percutaneous cannulation of the internal jugular or

femoral vein is performed.

Vascular Access for Hemodialysis

20

Fig. 47-8. Vascular access for hemodialysis. A, Arteriovenous fistula. B, Arteriovenous graft.


21

Arteriovenous Fistula

Fig. 47-9. Arteriovenous fistula created by anastomosing an artery and vein.


Arteriovenous fistula created by

anastomosing an

artery and vein.

A subcutaneous arteriovenous

fistula (AVF) is

most commonly

created in the

forearm with an

anastomosis

between an artery

and a vein (usually

cephalic).

22

Vascular Access Catheter

Fig. 47-10. Temporary double-lumen vascular access catheter for acute hemodialysis. A, Soft, flexible

double-lumen tube is attached to a Y hub. B, The distance between the arterial intake and the venous

return lumina typically provides recirculation rates of 5% or less.


23

Vascular Access Catheter

Fig. 47-11. A, Right internal jugular placement for a tunneled, cuffed semipermanent catheter.

B, Temporary hemodialysis catheter in place. C, Long-term cuffed hemodialysis catheter.

24

Hemodialysis

Dialyzers

Long plastic cartridge that contains thousands of

parallel hollow tubes or fibers

Fibers are the semipermeable membrane.

The blood is pumped into the top of the cartridge

and is dispersed into all of the fibers.

Dialysis fluid (dialysate) is pumped into the

bottom of the cartridge and bathes the outside of

the fibers with dialysis fluid.

25

Hemodialysis

Procedure

Two needles placed in fistula or

graft

Needle closer to fistula or red catheter lumen

pulls blood from patient and sends to dialyzer.

Blood is returned from dialyzer to patient

through second needle or blue catheter.

Heparin is added to the blood as it flows into

the dialyzer because any time blood contacts

a foreign substance, it has a tendency to clot.

Components of Hemodialysis


Blood is removed via a

needle inserted into a

fistula or via catheter

lumen. It is propelled to

the dialyzer by a blood

pump. Heparin may be

infused as a bolus

predialysis or through a

heparin pump

continuously to prevent

clotting. Dialysate is

pumped in and flows in

the opposite direction

of the blood. The

dialyzed blood is

returned to the patient

through a second

needle or catheter

lumen. Old dialysate

and ultrafiltrate are

drained and discarded

27

Hemodialysis

Procedure

Dialyzer/blood lines primed with saline

solution to eliminate air

Terminated by flushing dialyzer with saline

to remove all blood

Needles removed and firm pressure

applied

28

Hemodialysis

Procedure

Before treatment, nurse should

Complete assessment of fluid status,

condition of access, temperature, and

skin condition

During treatment, nurse should

Be alert to changes in condition

Perform vital signs every 30 to 60 minutes

The difference between the last

postdialysis weight and the present

predialysis weight determines the

29

Hemodialysis

Complications

Hypotension

Muscle cramps

Loss of blood

Hepatitis

Hypotension that occurs during HD primarily results from rapid removal of

vascular volume (hypovolemia), decreased cardiac output, and decreased

systemic intravascular resistance.

Factors associated with the development of muscle cramps include

hypotension, hypovolemia, high ultrafiltration rate (large interdialytic weight

gain), and use of low-sodium dialysis solution.

Blood loss may result from blood not being completely rinsed from the

dialyzer, accidental separation of blood tubing, dialysis membrane rupture, or

bleeding after the removal of needles at the end of dialysis.

At one time, hepatitis B had an unusually high prevalence in dialysis patients,

but the incidence today is quite low.

30

Hemodialysis

Effectiveness

Cannot fully replace metabolic & hormonal functions of kidneys

Can ease many of the symptoms

Can prevent certain complications

Dependence on a machine is a reality

Many patients question whether it is worthwhile

HD does not alter the accelerated rate of development of cardiovascular

disease and the related high mortality.

The yearly death rate of patients receiving maintenance dialysis remains

high and is estimated to be between 19% and 24%.

Individual adaptation to maintenance HD varies considerably. Initially,

many patients feel positive about the dialysis because it makes them feel

better and keeps them alive, but often great ambivalence is expressed

about whether it is worthwhile.

31

Comparison of methods of dialysis

Peritoneal Dialysis Hemodylsis

Immediate initiation Rapid fluid removal

Less complicated Rapid removal of urea and

creatinine

Portable system Effective K+ removal

Fewer dietary restrictions Less protein loss

Usable in patients with

vascular access problems

Lowers serum triglycerides

Less cardiovascular stress Home dialysis is possible as

temporary access can be

provided at home

Home dialysis possible

Preferred for diabetic

patients

These are the

advantages there are as

discussed previously

there are disadvantages

of both One of the

problems with

hemodialysis is the

amount of equipment

required which is not

portable and problems

with hypotension during

dialysis dietary and fluid

restrictions specially

trained personal required.

Similar problems with the

requirement for surgery

and body image issues re

access sites for both.

32

Priority Nursing Assessments

Dietary restrictions

Uremic frost

Muscle strength, energy

Family members

Excess fluid volume

Decreased cardiac output

Recombinant human erythropoietin

Interdisciplinary team

class %2318 - dialysis pp (2

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