Renal replacement therapy - dialysis Flashcards
What are the symptoms of uraemia?
Malaise and fatigue Nausea Vomiting Fatigue Anorexia Weight loss Muscle cramps Pruritus Mental status changes
What are the clinical signs of uraemia?
Muscle atrophy Loss of appetite Tremors Abnormal mental function Frequent shallow respiration Metabolic acidosis
What are the functions of the kidneys?
- Excretion of nitrogenous waste products (urea)
- Maintenance of acid and electrolyte balance
- Control of blood pressure
- Drug metabolism and disposal
- Activation of vitamin D
- Production of erythropoietin
What is uraemia?
Uremia is the condition of having “urea in the blood”. Urea is one of the primary components of urine. It can be defined as an excess of amino acid and protein metabolism end products, such as urea and creatinine, in the blood that would be normally excreted in the urine. The Uremic Syndrome can be defined as the terminal clinical manifestation of kidney failure (also called renal failure)
Define end stage renal disease
“…irreversible damage to a person’s kidneys so severely affecting their ability to remove or adjust blood wastes that, to maintain life, he or she must have either dialysis, or a kidney transplant…”
When is renal replacement therapy indicated?
Usually indicated when eGFR <10 ml/min.
What types of RRT are available?
Renal transplant
Haemodialysis
• Home haemodialysis
• Satellite / hospital haemodialysis
Peritoneal dialysis
• Continuous ambulatory peritoneal dialysis (CAPD)
• Intermittent peritoneal dialysis (IPD)
Conservative Kidney Management
What is dialysis?
Dialysis is a process whereby the solute composition of a solution, A, is altered by exposing solution A to a second solution, B, through a semipermeable membrane
List the 2 basic principles of dialysis
Diffusion
Ultrafiltration
What prerequisites are required for dialysis?
- Semipermeable membrane (artificial kidney in haemodialysis or peritoneal membrane)
- Adequate blood exposure to the membrane (extracorporeal blood in haemodialysis, mesenteric circulation in PD)
- Dialysis Access - vascular in haemodialysis, peritoneal in PD
- Anticoagulation in haemodialysis
How can we acquire access to the bloodstream for haemodialysis (both permanent and temporary options)?
Permanent
– Arteriovenous fistula
– AV prosthetic graft
Temporary
– Tunnelled venous catheter
– Temporary venous catheter
List the restrictions required while on dialysis
Fluid restriction
– Dictated by residual urine output
– Interdialytic weight gain
Dietary restriction
– Potassium
– Sodium
– Phosphate
How often is haemodialysis carried out?
3-5 times a week
Describe peritoneal dialysis
A balanced dialysis solution is instilled into the peritoneal cavity via a tunnelled, cuffed catheter, using the peritoneal mesothelium as a dialysis membrane
After a dwell time the fluid is drained out and fresh dialysate is instilled. Check drained fluid for signs of infection e.g. cloudiness, then pour away
Describe haemodialysis
- In haemodialysis, the patient’s blood is pumped through the blood compartment of a dialyzer, exposing it to a partially permeable membrane. The dialyzer is composed of thousands of tiny hollow synthetic fibers. The fiber wall acts as the semipermeable membrane.
- Blood flows through the fibers, dialysis solution flows around the outside of the fibers, and water and wastes move between these two solutions. The cleansed blood is then returned via the circuit back to the body.
- Ultrafiltration occurs by increasing the hydrostatic pressure across the dialyzer membrane. This usually is done by applying a negative pressure to the dialysate compartment of the dialyzer.
- This pressure gradient causes water and dissolved solutes to move from blood to dialysate and allows the removal of several litres of excess fluid during a typical 4-hour treatment.
