Renal Replacement Flashcards
4 renal functions
excretory function
water and electrolyte balance
acid base balance
- compensate with ventilation partly
renal endocrine function
- erythropoietin – RBC
- calcium metabolism – vit D production of Ca Metabolism
- renin secretion
how are renal endocrine functions dealt with in renal failure
medically - with injections
how are renal excretory, water and electrolyte and acid base balance functions dealt with in renal failure
with renal replacement
what type of process is renal dialysis
passive
diffusion down concentration gradient
what does the dialysis machine facilitate in renal replacement
Allows intermittent correction of changes in plasma concentration of small molecules
Blood with desired and undesired components
- Thin membrane
Causing undesired to move out and more desired to move in
what impact does renal dialysis have on the pt lifestyle
significant restrictions remain
Not connected 24/7
- Stop dialysis get worse again
- Build up until plugged in again
- Tends to affect how pt feels - up and down
Keep blood at tip top all the time
- Better than no kidney function
- Any water that you take in as to go out through dialysis
Restricted in types can eat and fluid drink. As only up to limit by what is achieved by dialysis
where does haemodialysis occur
outside the body
where does peritoneal dialysis occur
inside the body
using peritoneum as dialysing machine
Peritoneum (gut bag), exposed thin layer of BV
- Machine into meet the blood rather than blood out to
what are the 2 types of dialysis
heamodialysis and peritoneal dialysis
what do you need to do to a body’s circulatory system to perform heamodialysis
Need to short circuit some body’s system so faster
- Pressure in artery high, vein low
- Lots of blood through loop
Vein increases
- Easier to out cannula in
- Suitable access point for dialysis
Undergo diffusion process in machine
what do you need to add to blood to prevent it clotting in the haemodialysis machine
heparin
so blood become anti-coagulated
- passes down through the dialyser
what is the dialyser tube like
Filled with tubes surrounded by dialyising solution
what do the thin membranes of the dialyser tube permit
thin membranes maximise area between dialysing solution and blood
what influences the time between dialysis and no dialysis in haemodialysis
Cycle of dialysis and no dialysis
Time between depends on kidney function level
- Can be overnight - infection control issue for haemodialysis
so less common
what additional modifications to you need on a haemodialysing machine so it works effectively
Heaters to warm up solution
Traps to prevent air in
pumps to keep pressure
heparin for anti-coagulation
what is a basic description of the process of dialysis
Purely passive diffusion down to concentration gradients between blood and dialysing solution
Effectively like clingfilm with tiny holes in it
- Depending on size of hole in that membrane
- Too large to let big ions through
Design membrane to allow electrolyte exchange, protein exchange
Design dialysing solution on one side to be what you want to achieve on the other (blood)
- Create a concentration gradient for ions to move in/or of blood
- Dialysing solution should be opposite of blood
- –High in solution - move in
- –Low in solution - move out of blood
how should you design the dialysing solution
Design dialysing solution on one side to be what you want to achieve on the other (blood)
- Create a concentration gradient for ions to move in/or of blood
- Dialysing solution should be opposite of blood
- –High in solution - move in
- –Low in solution - move out of blood
what should the dialysing solution be compared to blood
opposite of what you want the blood to be
peritoneal dialysis process
Surface of bowel loops hasn’t got epithelial covering on it
- Behave like dialysing straws -enough diffusion occurring
Fluid into peritoneum not machine
- Sealed bag with intestines on inside
- Tube in - fluid stay as sealed off
Stay around outside of gut loops
After a while chance to equilibrate
Inside body rather than outside in machine
Suck into drainage contained – back out
what is the tube like in the implanted catheter
like a leaky garden hose
where is the implanted catheter positioned
Positioned inside peritoneum
Bath peritoneal cavity
3 advantages of peritoneal dialysis
Different patterns to use
- Can do day and night
- Can do at side of bed - no blood tubes
- Can do only at night
Can do at home so can do every day
- Meaning no bad days
- Mimics more natural kidney condition
Machine can go in suitcase - All need bags of fluid - More flexible system - More able to travel and work Overnight dialysis
disadvantage of peritoneal dialysis
In charge of own life/death
- Lots of responsibility on pt - May dislike
disadvantage of haemodialysis
Cannot go away for a day
- Otherwise needs to go to a place where hospital able to do dialysis and spend lots of time on dialysis
