Dialysis Flashcards
what does dialysis do?
removes urea, K+ and Na+ while infusing HCO3-
restrictions on patients on dialysis
fluid
salt
K+
phosphate (phosphate binders should be taken with meals)
two types of dialysis
haemodialysis
peritoneal dialysis
upgraded version of HD
haemodiafiltration (HDF)
how does HD work
solutes are dragged across a semi-permeable membrane in response to a pressure gradient
how often is HD done?
hospital for 4 hours 3 times a week
gradual build-up to begin with
vascular access options for HD
- fistula
2. tunnelled venous catheter
fistula in HD
artery and vein connected creating an enlarged vein which requires surgery and maturation for 6-12 weeks
sites of fistula
radio-cephalic (RC AVF)
brachio-cephalic (BC AVF)
brachio-basilic transposition (BB AVF)
adverse of fistula
surgery
cannot be used immediately
can reduce blood flow to distal arm
describe tunnelled venous catheter
catheter inserted into a large vein (internal jugular) which can be used immediately
adverse of tunnelled venous catheter
infection
blockage
how does peritoneal dialysis work?
uses the peritoneal membrane to transfer substances
can PD be done at home
yes
two types of PD
continuous ambulatory PD (CAPD)
automated PD
describe CAPD
4 x 2L bag exchange per day
describe APD
1 bag all day and overnight machine controls fluid drainage
adverse of PD
infection
peritoneal membrane failure
hernia (increased intra-abdominal pressure)
training required (begin with small volumes)
complications of dialysis
hypotension
haemorrhage (rupture AVF)
arrhythmias (electrolyte imbalance)
define intra-dialytic hypotension
myocardial stunning due to removal of large volumes of H2O 3 times a week leading to underfilling of intravascular space and low BP
indications for dialysis
resistant hyperkalaemia eGFR <7ml/min urea >40mmol/L unresponsive acidosis symptomatic e.g. itch, fluid overload, fatigue, anorexia
