renal replacement therapy Flashcards
what are the functions of the kidneys?
Excretion of nitrogenous waste products
Maintenance of acid and electrolyte balance
Control of blood pressure
Drug metabolism and disposal
Activation of vitamin D
Production of erythropoietin
what is 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
what are clinical features of advanced CKD?
Until CKD stage 4 or 5 the patient may be asymptomatic
The syndrome of advanced CKD is called uraemia
Uraemic symptoms can involve almost every organ system but the earliest and cardinal symptom is malaise and fatigue
is CKD ussually symptomatic?
no
when is RRT ussually indicated?
when eGFR <10ml/min
what are different types of renal replacement therapy?
Renal transplant
Haemodialysis
Home haemodialysis
Satellite / hospital haemodialysis
Peritoneal dialysis
Continuous ambulatory peritoneal dialysis (CAPD)
Intermittent peritoneal dialysis (IPD)
Conservative Kidney Managemen
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.
what is the first principle of dialysis?
diffusion
what is the second principle of dialysis?
ultrafiltration
what are pre-requisites for dialysis?
Semipermeable membrane (artifical 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 hemodialysis
what are permanent haemodialysis accesses?
Arteriovenous fistula
AV prosthetic graft
what are temporary haemodualysis accesses?
Tunnelled venous catheter
Temporary venous catheter
how does dialysis work?
what are restrictions for dialysis patients?
Dictated by residual urine output
Interdialytic weight gain
Potassium
Sodium
Phosphate
describe the process of haemodialysis?
what is 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
Continuous Ambulatory Peritoneal Dialysis (CAPD),
Automated Peritoneal Dialysis (APD)
Hybrid
what does dialysis fluid contain?
The dialysate contains a balanced concentration of electrolytes
Glucose is the most common osmotic agent for ultrafiltration of fluid
The peritoneal transport characteristics can vary from high transporter to low transporter
Dwell times can be adjusted according to transport characteristics
what is the regime for CAPD?
what is the regime for APD?
complications of peritoneal dialysis?
Exit site infection
PD peritonitis
Gram positive – skin contaminant
Gram negative – bowel origin
Mixed – suspect complicated peritonitis eg perforation
Ultrafiltration failure
Encapsulating peritoneal
what are indications for dialysis in end stage renal disease?
Advanced uraemia, (GFR 5-10 ml/min)
Severe acidosis (bicarbonate <10 mmol/l)
Treatment resistant hyperkalaemia (K >6.5 mmol/l)
Treatment resistant fluid overload
Nephrologist’s clinical judgment is important
what is the fluid balance for haemodialysis?
Usually restricted to 500-800 ml/24 hours intake allowed = urine output +insensible loss
what is the fluid balance for Peritoneal dialysis?
Usually more liberal intake as continuous ultrafiltration is often achieved
what are dialysis related drugs?
Anaemia
Erythropoietin injections
IV iron supplements
Renal Bone Disease
Activated Vitamin D (eg calcitriol)
Phosphate binders with meals (CaCo3)
Heparin
Water soluble vitamins
? antihypertensives
what are complications of haemodialysis?
Cardiovasular problems
Intra-dialytic hypotension and cramps
Arrythmias
Coagulation
Clotting of vascular access
Heparin related problems
Other
Allergic reactions to dialysers and tubing
Catastrophic dialysis accidents (rare)
what are complications of peritoneal dialysis?
Infection
Exit site infection
Tunnel infection
Peritonitis
Mechanical
Tube malfunction
Abdominal wall herniae
Ultrafiltration problems
how is the decision for choice of dialysis modality chosen?
Patient choice – most important
Education
Shared decision making
Patient related
Perceptions of effectiveness
(Cost and remuneration)
what are limitations of dialsysis?
Dialysis of whatever type is a woeful substitute for the kidneys
However it is the only means of keeping patients with ESRD alive
But might not be right for everyone
what is conservative kidney management?
Supportive care
Priority for symptomatic management
Holistic multi-professional approach
Anticipatory care planning
Randomised control trial ongoing for dialysis versus CKM for older adults with co-morbidity
