Dialysis and kidney transplant summary
guide with questions and answers
What is dialysis and what are the two types?
Dialysis is the movement of fluid and molecules across a semipermeable membrane from one
compartment to another. Clinically, dialysis is a technique in which substances move from
the blood through a semipermeable membrane (dialyzer) and into a dialysis solution
(dialysate).
• Used to correct fluid and electrolyte imbalances and to remove waste products in renal
failure
• Can also be used to treat drug overdoses
The two methods of dialysis available are peritoneal dialysis and
hemodialysis (Table 49.13).
Table 49.13 Comparison of Peritoneal Dialysis and Hemodialysis
Peritoneal Dialysis Hemodialysis
Advantages
• Fewer dietary restrictions Effective potassium removal
• Home dialysis possible Home dialysis possible
• Less cardiovascular stress
Less protein loss than with
• Less complicated than hemodialysis
peritoneal dialysis
• Portable system with CAPD Preferable for Lowering of serum triglycerides
the diabetic patient Rapid fluid removal
Rapid removal of urea and
• Relatively short training time
creatinine
pg. 1
, • Usable in the patient with vascular access Temporary access can be placed
difficulties at bedside
Disadvantages
• Catheter can migrate • Added blood loss that
contributes to anemia
• Contraindication in the patient with multiple
abdominal surgeries, trauma, unrepaired • Dietary and fluid restrictions
hernia
• Extensive equipment necessary
• Protein loss into dialysate
• Heparinization may be
• Risk for aggravated dyslipidemia necessary
• Risk for bacterial or chemical peritonitis • Hypotension during dialysis
• Risk for exit-site and tunnel infections • Longer training time for home
hemodialysis vs. peritoneal
• Risk for hyperglycemia
• Self-image challenges with
• Risk for self-image challenges with
Peritoneal Dialysis Hemodialysis
catheter placement permanent access
• Surgery for catheter placement Specially trained personnel
necessary (if in-centre option
chosen)
pg. 2
,• Surgery for permanent access placement Vascular access difficulties
CAPD, continuous ambulatory peritoneal dialysis.
There are varying indications for PD and HD.
Types of Dialysis Peritoneal Dialysis
• A method of removing waste products using the peritoneum.
• Dialysis fluid is infused into the peritoneal cavity.
• Excess fluid and waste products pass across the membrane into the fluid, that is then
drained and discarded.
Hemodialysis
• Waste products and excess fluid are removed from the blood using a machine to
pump the blood through an artificial semipermeable membrane (usually made of
cellulose-based or synthetic materials).
Dialysis therapy is initiated when CKD progresses to the point where the following cannot be
managed:
• The patient’s symptoms
• Fluid volume status
Generally, dialysis is initiated when the GFR (or creatinine clearance) is less than 15
mL/min/1.73 m2. Certain uremic complications indicate a need for immediate dialysis
including:
• Encephalopathy
• Neuropathies
• Uncontrolled hyperkalemia
• Pericarditis
• Accelerated hypertension
pg. 3
, • What are the general principles of dialysis?
• Solutes and water move across the semipermeable membrane from the blood to the
dialysate or from the dialysate to the blood, in accordance with concentration
gradients (Fig. 49.5).
The principles of diffusion, osmosis, and ultrafiltration are involved in dialysis.
Principles of Dialysis
Diffusion: the movement of solutes from an area of greater concentration to an area of lesser
concentration Renal Failure:
• Urea, creatinine, uric acid, and electrolytes (potassium, phosphate) move from the
blood to the dialysate with the net effect of lowering their concentration in the blood.
• RBCs, WBCs, and plasma proteins are too large to diffuse through the pores of the
membrane.
• Bacteria and viruses that may be present in the dialysate are too large to migrate
through the pores into the blood.
Osmosis: the movement of fluid from an area of lesser to an area of greater
concentration of solutes Glucose:
• Added to the dialysate and creates an osmotic gradient across the membrane, pulling
excess fluid from the blood.
pg. 4
guide with questions and answers
What is dialysis and what are the two types?
Dialysis is the movement of fluid and molecules across a semipermeable membrane from one
compartment to another. Clinically, dialysis is a technique in which substances move from
the blood through a semipermeable membrane (dialyzer) and into a dialysis solution
(dialysate).
• Used to correct fluid and electrolyte imbalances and to remove waste products in renal
failure
• Can also be used to treat drug overdoses
The two methods of dialysis available are peritoneal dialysis and
hemodialysis (Table 49.13).
Table 49.13 Comparison of Peritoneal Dialysis and Hemodialysis
Peritoneal Dialysis Hemodialysis
Advantages
• Fewer dietary restrictions Effective potassium removal
• Home dialysis possible Home dialysis possible
• Less cardiovascular stress
Less protein loss than with
• Less complicated than hemodialysis
peritoneal dialysis
• Portable system with CAPD Preferable for Lowering of serum triglycerides
the diabetic patient Rapid fluid removal
Rapid removal of urea and
• Relatively short training time
creatinine
pg. 1
, • Usable in the patient with vascular access Temporary access can be placed
difficulties at bedside
Disadvantages
• Catheter can migrate • Added blood loss that
contributes to anemia
• Contraindication in the patient with multiple
abdominal surgeries, trauma, unrepaired • Dietary and fluid restrictions
hernia
• Extensive equipment necessary
• Protein loss into dialysate
• Heparinization may be
• Risk for aggravated dyslipidemia necessary
• Risk for bacterial or chemical peritonitis • Hypotension during dialysis
• Risk for exit-site and tunnel infections • Longer training time for home
hemodialysis vs. peritoneal
• Risk for hyperglycemia
• Self-image challenges with
• Risk for self-image challenges with
Peritoneal Dialysis Hemodialysis
catheter placement permanent access
• Surgery for catheter placement Specially trained personnel
necessary (if in-centre option
chosen)
pg. 2
,• Surgery for permanent access placement Vascular access difficulties
CAPD, continuous ambulatory peritoneal dialysis.
There are varying indications for PD and HD.
Types of Dialysis Peritoneal Dialysis
• A method of removing waste products using the peritoneum.
• Dialysis fluid is infused into the peritoneal cavity.
• Excess fluid and waste products pass across the membrane into the fluid, that is then
drained and discarded.
Hemodialysis
• Waste products and excess fluid are removed from the blood using a machine to
pump the blood through an artificial semipermeable membrane (usually made of
cellulose-based or synthetic materials).
Dialysis therapy is initiated when CKD progresses to the point where the following cannot be
managed:
• The patient’s symptoms
• Fluid volume status
Generally, dialysis is initiated when the GFR (or creatinine clearance) is less than 15
mL/min/1.73 m2. Certain uremic complications indicate a need for immediate dialysis
including:
• Encephalopathy
• Neuropathies
• Uncontrolled hyperkalemia
• Pericarditis
• Accelerated hypertension
pg. 3
, • What are the general principles of dialysis?
• Solutes and water move across the semipermeable membrane from the blood to the
dialysate or from the dialysate to the blood, in accordance with concentration
gradients (Fig. 49.5).
The principles of diffusion, osmosis, and ultrafiltration are involved in dialysis.
Principles of Dialysis
Diffusion: the movement of solutes from an area of greater concentration to an area of lesser
concentration Renal Failure:
• Urea, creatinine, uric acid, and electrolytes (potassium, phosphate) move from the
blood to the dialysate with the net effect of lowering their concentration in the blood.
• RBCs, WBCs, and plasma proteins are too large to diffuse through the pores of the
membrane.
• Bacteria and viruses that may be present in the dialysate are too large to migrate
through the pores into the blood.
Osmosis: the movement of fluid from an area of lesser to an area of greater
concentration of solutes Glucose:
• Added to the dialysate and creates an osmotic gradient across the membrane, pulling
excess fluid from the blood.
pg. 4
