Download Composition of peritoneal fluid in relation to peritoneal dialysis

Composition of peritoneal fluid in
relation to peritoneal dialysis
Learning Objectives
At the end of the lecture student should be able to understand
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Dialysis and its types
Peritoneal dialysis indications
Principal of peritoneal dialysis
Composition of peritoneal dialysis solution
Significance of different constituents of PD solution
Types of peritoneal dialysis
Complications of peritoneal dialysis
Dialysis
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Method of removing toxic substances (impurities or wastes) from the blood when the
kidneys are unable to do so
Most frequently used for patients who have kidney failure, but may also be used to quickly
remove drugs or poisons in acute situations
Two methods: hemodialysis and peritoneal dialysis
Overview
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Peritoneal dialysis (PD) is a treatment for patients with severe chronic kidney disease.
The process uses the patient's peritoneum in the abdomen as a membrane across which
fluids and dissolved substances (electrolytes, urea, glucose, albumin and other small
molecules) are exchanged from the blood.
Fluid is introduced through a permanent tube in the abdomen and flushed out either
every night while the patient sleeps (automatic peritoneal dialysis) or via regular
exchanges throughout the day (continuous ambulatory peritoneal dialysis).
Overview
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Used as an alternative to hemodialysis though it is far less common.
It has comparable risks and expenses, with the primary advantage being the ability to
undertake treatment without visiting a medical facility.
The primary complication with peritoneal dialysis is a risk of infection due to the presence
of a permanent tube in the abdomen.
Principles of peritoneal dialysis
Principle
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Dialysis fluid is introduced to the peritoneal cavity through a catheter placed in the lower
part of the abdomen.
A thin membrane, called the peritoneum, lines the walls of the peritoneal cavity and
covers all the organs contained in it.
In Peritoneal Dialysis the peritoneum serves as the dialysis membrane. The peritoneal
cavity can often hold more then 3 litres, but in clinical practice only 1.5 – 2.5L of fluid are
used.
This is an intra-corporeal blood purification as no blood ever leaves the body of the
patient.
Principle
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The abdominal cavity, hold the large organs of the digestive system, is
lined by the peritoneum.
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In Peritoneal dialysis, special fluid is instilled through a permanent
catheter in the lower abdomen.
Composition of standard peritoneal dialysis solution
Principle
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An osmotic pressure gradient is applied by the addition to
the dialysis fluid of an osmotic agent which will “suck” fluid
from the blood.
The concentration of this osmotic agent is chosen to give
just the fluid removal needed. In most cases glucose is used
to create the osmotic pressure.
Fluid is removed by ultrafiltration driven by an osmotic
pressure gradient. (Eg. Yellow/Green/Red Bags)
Principle
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Solutes are transported across the membrane by diffusion.
The driving force is the concentration gradient between the PD
fluid and the blood.
Waste products present in the blood per fusing the peritoneum
will diffuse from the blood vessels into the “cleaner” dialysis
fluid.
Principle
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The dialysis fluid should be instilled for 4 to 6 hours.
When the dialysis fluid is drained from the abdominal cavity, it
contains waste products and excess fluid extracted from the
blood.
PD is most often applied and effective as a continuous therapy. In
this way it is a more physiological treatment then Haemodialysis
(HD)
Principle
The Peritonium
The Peritonium
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It is a loose connective tissue containing blood vessels and
nerves.
If put under the microscope, three layers can be identified
between the peritoneal cavity and the blood stream.
The capillary wall / the interstitium / the mesothelium
Each of these is a barrier to the transport of fluid and solutes.
Peritoneal Dialysis Fluid
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Components of PD fluid can be divided in into electrolytes, buffer and osmotic agents.
The most abundant electrolyte in PD fluid is sodium. It’s hyponatremic, so it has a
concentration lower than blood to ensure sufficient removal of sodium.
Standard PD fluid contains no potassium.
Today, there is a tendency to use normcalcemic PD fluid as many patients receive extra
calcium from phosphate-binding drugs.
The buffer normally used in PD is lactate. Lactate is metabolised to form bicarbonate, the
most important buffer in the blood.
Peritoneal Dialysis Fluid
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The major osmotic agent used today is glucose.
As the rate of fluid transport is related to the osmotic strength of the PD solution, the
ultrafiltration can be controlled by an appropriate glucose concentration
Glucose is not ideal, as it is rapidly absorbed from the PD fluid. This may lead to problems
with fluid removal, patient gains calories and can lose there appetite. Resulting in
overweight and malnourishment. Disturbances of the carbohydrate and lipid metabolism
may also occur.
Research to find alternative osmotic agents has resulted in new products which are still
not widely used. Amino acids are an interesting alternative as they provide nutritional
supplement.
High molecular weight glucose polymer (extraneal/icodextrin) provide sustained
ultrafiltration for long overnight dwells.
Types of Peritoneal Dialysis
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There are two types ;
Continuous Ambulatory Peritoneal Dialysis (CAPD)
Automated Peritoneal Dialysis (APD)
Peritoneal Dialysis: Complications
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Peritonitis
 Signs: cloudy bag, stomach pain, fever
 If suspected, obtain a culture of the outflow to
determine the infective organism
Abdominal Pain
 Pain during inflow is common during the 1st few
exchanges & usually disappears 1 to 2 wks of
dialysis treatments
 Place heating pad
Insufficient Outflow
 Check for kinks and placement; refer to physician
 Encourage high-fiber diet
Leakage around the catheter site
 May take up to 2 wks for client to tolerate a full 2L
exchange w/o leaking around the catheter site
Bladder or Bowel Perforation
Peritoneal Dialysis Treatment
Adequate Patient Care in the Most
Biocompatible Way