Renal Replacement Therapy 1 (Dialysis) Flashcards
whata re the functions of the kidney?
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
(a hormone produced mainly by the kidneys. It is produced and released into the bloodstream if the blood oxygen levels are low (hypoxaemia). Erythropoietin is carried to the bone marrow, where it works to stimulate stem cells to become red blood cells (RBCs))
What is End-stage renal disease (ESRD)
“…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 the 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
what is renal replacement therapy?
The means by which life is sustained in patients suffering from end-stage renal disease
when is renal replacement therapy usually indicated?
Usually indicated when eGFR <10 ml/min
eGFR at start is variable between individuals
what are the 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 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.
What is 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 ways of access for haemodialysis?
• Permanent
- Arteriovenous fistula
- AV prosthetic graft
• Temporary
- Tunnelled venous catheter
- Temporary venous catheter
What is dialysate?
Dialysate is the fluid that is used in dialysis to adjust the extracellular fluid composition and to maintain body homeostasis
what restircations is there for dialysis patients?
• Fluid restriction
- Dictated by residual urine output
- Interdialytic weight gain
• Dietary restriction
- Potassium
- Sodium
- Phosphate
what is the difference between haemodilysis and peritoneal dialysis?
There are two kinds of dialysis. In hemodialysis, blood is pumped out of your body to an artificial kidney machine, and returned to your body by tubes that connect you to the machine. In peritoneal dialysis, the inside lining of your own belly acts as a natural filter
Your doctor will create a vascular access site in the arm before hemodialysis. Peritoneal dialysis, on the other hand, requires a catheter, or piece of tubing, placed in your belly. Hemodialysis uses a man-made membrane called a dialyzer to clean the blood, whereas peritoneal dialysis uses the lining of your belly
how is Peritoneal dialysis carried out?
- 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
what are the different types of peritoneal dialysis?
- Continuous Ambulatory Peritoneal Dialysis (CAPD),
- Automated Peritoneal Dialysis (APD)
- Hybrid
what are periotneal dialysis fluids?
- 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
Pictures showing difference between CAPD and APD
what are some ocmplications 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 sclerosis
what are some indications for dialysis in ESRD?
- 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 fluid balance like in dialysis patients? (haemodialysis and peritoneal dialysis)
- Haemodialysis - Usually restricted to 500-800 ml/24 hours intake allowed = urine output +insensible loss
- 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 some 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 some complications of peritoneal dialysis
Infection:
- Exit site infection
- Tunnel infection
- Peritonitis
Mechanical:
- Tube malfunction
- Abdominal wall herniae
Ultrafiltration problems
how is the choice of dialysis modality made?
• Patient choice - most important
- Education
- Shared decision making
- Patient related
- Perceptions of effectiveness
- (Cost and remuneration)
wht are the limitations of dialysis?
- 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
picture showing - Mortality Rates for US Dialysis Patients
what is conservative kidney managament?
• 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
picture showing - RRT incidence rates between 1980 and 2015
Summary:
- Principles of dialysis are _______ and ___________
- Indicated when eGFR less than __ ml/m or patient symptomatic of _______
- Two main types: _______ and _________ ________
- Patients on dialysis have increased ______ and ______ and are faced with dietary and fluid restrictions
diffusion and ultra-filtration
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uraemia
haemodialysis and peritoneal dialysis
morbidity and mortality
