renal dialysis: basic concepts and applications Flashcards
abrupt decline in kidney function (decreased GFR) that may result in:
- retention of nitrogenous wastes and uremic toxins
- dysregulation of extracellular volume
- electrolyte imbalance
- metabolic acidosis
decline in GFR is recognized clinically via increases in:
BUN and creatinine
what are causes of AKI
- ischemic (pre-renal)
- intrinsic (renal)
- post-renal
what are the indications for RRT
- AKI or AoCKD, ESKD
- failure to respond to traditional supportive management strategies
- oliguria or anuria
- fluid overload
- intoxications
failure to respond to traditional supportive management strategies include:
- progressive azotemia
- metabolic acidosis
- electrolyte abnormalities
- intractable clinical signs
AEIOU
- acid-base (acidemia)
- electrolyte (K+)
- intoxications (drugs)
- overload (fluid)
- uremia
how does hemodialysis clean the blood
* through the process of diffusion
* by breaking down waste products
* through removing excess fluids from the blood
through the process of diffusion
what is diffusion
movement of solutes between two aqueous solutions separated by a semi-permeable membrane
what does diffusion depend on
- concentration gradient
- solute charge
- molecular weight
- surface area and permeability of the membrane
ultrafiltration
plasma water is removed by application of a transmembrane pressure
convective clearance
solute removal occurs when solutes are dragged along with plasma water either as a result of an osmotic or hydrostatic pressure
how is convective clearance determined
by the ultrafiltration rate or the size of the pores in the membrane
how does hemodialysis work
- blood is removed from the body via a large bore catheter
- anticoagulated blood flows through the extracorporeal circuit containing the dialyzer (artificial kidney) (subtances can be added or removed)
- treated or “clean” blood is returned to the patient
catheter placement
- surgical preparation
- large, dual lumen catheter
- jugular vein
- right > left
how does the dialyzer work
- blood and dialysate flow in a countercurrent direction to maximize diffusion
- blood flows through the INSIDE of the tiny straws
- dialysate flows around the OUTSIDE of the tiny straws
- dialysate speed > blood
- generated from ultra pure water, acid, base and electrolytes
- specifically generated for each tx based on the tx prescription
- heated to help maintain patients body temp
how is the dialysis similar to the kidney
- removes waste products from the blood
- remove drugs from the body
- balances the body’s fluids
the bowmans capsule acts like a:
semi-permeable membrane
____ multiplication in the loop of henle
countercurrent
what can dialysis NOT do
- regulate blood pressure (via hormones)
- produce an active form of VD
- control the production of RBC (via epoetin)
