Flashcards in Dialysis- Final Exam Deck (84)
What are some convection based alternative hemodialytic techniques?
CAVH (continuous arteriovenous hemofiltration)
CVVH (continuous venovenous hemofiltration)
What are some diffusive therapy based alternative hemodialytic techniques?
CAVHD (continuous arteriovenous hemodialysis)
CVVHD (continuous venovenous hemodialysis)
How does blood circulate in continuous arterio-venous hemofiltration?
With or without a blood pump thrugh a small hollow-fiber hemofilter; through the hemofilter wherein the plasma and water is filtered and collected in the collection bag
Where do you get access in CAVH?
Femoral artery and vein
Where is heparin infused in CAVH?
Proximal to the dialyzer
Where is replacement volume infused in CAVH?
Into venous return line
Why is CVVH replacing CAVH mode?
Pump assisted and achieves higher clearance. Because of its effectiveness, it is replacing the pumpless CAVH mode
Where do you get access in CVVH?
Double lumen catheter in the femoral, SC, or IJ vein
How is continuous diffusive solute transport achieved in CVVH?
Infusing a dialysate flui
What is the counter-current rate in CVVH?
15 ml/min or 1 L/hr
CAVH/CVVH Mechanism of Action
-Solute removed by solvent drag
-roller pump creates hydrostatic pressure
-drives solute through membrane
-pore size limits transfer
-more efficient removal of larger molecules than diffusion
-enhanced cleared of autologous cytokines
CAVH/CVVH has enhanced clearance of what?
Describe the technique of CAVHD.
Infusion pump, dialyzer membrane and dialysate solution.
Infusion pump pushes a flow of dialysis fluid dialyzer. The blood/dialysate interfaces on the membrane. CAVHD uses the process of diffusion dialysis to rid the body of fluid, electrolytes and nitrogenous wastes.
What process does CAVHD use to rid the body of wastes?
What wastes does CAVHD get rid of?
Fluid, electrolytes, nitrogenous wastes
What is the preferred arterial access site for CAVHD?
What is more effective: CAVHD or CVVHD? Why?
CAVHD, becuase the lower pressure venous system does not filter as much blood per unit of time
CAVHD/CVVHD Mechanism of Action
-Solute diffuses electrochemical gradient
-diffusive movement; smaller molecule have greater KE removed based on size of gradient
-convection due to UF
-solute removed proportion to size
-dialysate flow is low that BFR
-solute removal directly proportion to dialysate flow rate
What type of cannulas are used for dialysis access?
duel lumen dialysis catheters
Surgically created arteriovenous fistulas are preferred over catheters for patients with chronic renal failure for ease of access and a lower infection risk
What is one the most common errors of dual lumen cathters?
Placement of arterial and venous ports on the catheters
What is used for anticoagulation?
What are some advantages of Citrate as an anticoagulant?
Citrate has the effect of anticoagulating the CVVVH system itself.
Citrate interrups the clotting cascade by soaking up (chelating) free ionized calcium. the citrate is cooked off (metabolized) into the form of bicarb