Module 3: Principles of Dialysis

53 cards

Principles of Dialysi


 
  
Created Sep 18, 2010
by
ameyer08

 

 
Table View
 
Download
 
Print

Flashcard Set Preview

  Side A   Side B
1
Dialysis replaces 3 main kidney functions
 

Removing wastes from the blood

Removes excess fluid from the blood

Keeping...

2
Solutions
 
a mixture of a solvent and a solute
3
Solvent
 
Fluid
4
Solute
 
any substance that can be dissolved into the solvent
5
Dialysate
 

the solution that is used during dialysis

Solvent: Water

Solute: Electrolytes...

6
Electrolyte Levels in Dialysate
 

closely match the levels in the human blood.

This reduced the loss of these electrolytes...

7
Controlling pts blood electrolyte levels
 

can be controlled by changing the dialysate.

Adding an electrolyte to the dialysate...

8
Semipermeable Membrane
 
a type of thin, flexible filter- a barrier that allows only particles smaller than a certain...
9
Dialysis semipermeable membrane
 
In dialysis, the semipermeable membrane's holes allow small molecules, such as water and urea,...
10
Diffusion
 

the process by which atoms, molecules, and/or other particles move from an area where they...

11
Energy for Diffusion
 
Energy for the movement comes from the molecules themselves, and does not depend on outside...
12
Factors affecting diffusion: The nature of the solution
 

Concentration Gradients

Molecular weight of the solutes

Temperature

13
Concentration Gradients
 

Solutes move through a semipermeable membrane from an area of greater concentration to an...

14
Molecular weight of the solution
 
Smaller molecules diffuse more easily and quickly than larger ones. Large blood components...
15
Temperature
 
Molecules move faster at higher temperatures, so warmer fluids allow faster diffusion. Dialysate...
16
Factors Affecting Diffusion: The Nature of the Membrane
 

Membrane permeability

Surface area of the membrane

Flow geometry

17
Membrane permeability
 
A membrane with more pores allows faster diffusion. Larger pores allow larger molecules to...
18
Surface area of the membrane
 
Surface area is the amount of membrane in direct contact with the blood and dialysate. Larger...
19
Flow geometry
 
In dialysis, blood flows one way while dialysate flows the opposite way. This countercurrent...
20
Osmosis
 

In diffusion, solutes move. In osmosis, the solvent moves across the membrane.

Osmosis...

21
Osmotic Pressure Gradient
 

The difference in concentration

 

22
Hydraulic pressure
 
Osmotic pressure can be overcome by hydraulic pressure using a pump, gravity or other means....
23
Reverse osmosis water treatment devices
 

Hydraulic pressure can reduce or overcome osmotic pressure. This principle is the basis...

24
Filtration
 
the movement of fluid through a filter as the result of hydraulic pressure. Fluid will always...
25
Ultrafiltration (UF)
 
Water removal from blood due to a pressure gradient across a membrane. In dialysis, UF is used...
26
Convection
 
transfer of heat and solutes by physical circulation or movement of the parts of a liquid or...
27
Solvent drag
 
as a solvent crosses a semipermeable membrane, it drags along smaller solutes
28
Fluid
 
a liquid or gas that changes shape at a steady rate when acted upon by a force
29
Dynamics
 
addreses the motion and equilibrium of systems
30
Fluid dynamics
 

describes how two fluids-blood and dialysate-are pumped through tubing. Several forces affect...

31
Flow rate
 
amount of fluid that flows through the tubing in a given period of time
32
Flow velocity
 

speed at which the fluid moves through a given length of tubing.

Velocity is based...

33
Pressure in any fluid system
 
the pressure in any fluid system is always related to the flow and the resistance; the greater...
34
Fluid compartments
 

The human body is made mostly of fluids. Fluids are found in 3 compartments:

Intracellular...

35
Pressure gradients in fluid compartments
 
Differences in the level of sodium and electrolytes between compartments (gradients) cause...
36
Dialysis and body compartments
 
During dialysis, only fluid from the intravascular compartment can be removed
37
Extracorporeal Circuit
 

Outside the body

Together, the tubing and dialyzer are called the extracorporeal...

38
Fluid intake
 

Food

Beverages

Intravenous fluids

39
Fluid Output
 

Respiration

Stool

Perspiration adn skin water loss

Dialysate loss

Residual...

40
Fluid dynamics in dialysis
 
blood pump speeds the flow of blood from the pt. Blood passes through the needle-the first...
41
Resistance in the blood pump
 

The tubing

The tiny hollow fibers in the dialyzer

The small opening of the...

42
Resistance in the blood pump creates:
 
positive pressure inside the lines and dialyzer fibers. As blood passes through these resistances,...
43
Venous pressure
 
The pressure measured after blood leaves the dialyzer (venous pressure) is the lowest positve...
44
Positive hydraulic pressure
 
The average pressure of blood entering and leaving the dialyzer fibers is the true amount of...
45
Countercurrent flow.
 
dialysate flows through the dialyzer and around the hollow fibers in one direction. Blood flows...
46
Transmembrane pressure (TMP)
 
The machine can control the pressure differential between the blood and dialysate compartment...
47
Diffusion in dialysis
 
The hollow fibers in the dialyzer are the semipermeable membrane. Blood passes through the...
48
Electrolyte balance in dialysis
 
is also maintained with diffusion. It is vital to pts health to keep the right level of electrolytes...
49
Diffusion occurs continuously in the pts body
 
as clenased blood is returned to the pt, it slowly dilutes the rest of the blood. The drop...
50
UF in dialysis
 
UF requires pressure to force fluid through the membrane. The dialysis machine can create a...
51
Convection in dialysis
 
As water (a solvent) moves from the blood compartment to the dialysate compartment, molecules...
52
Osmosis in dialysis
 
the pressure of UF pushes fluid out of the blood nad into the dialysate. But osmotic forces...
53
Example of FIltration and UF
 
Soak a sponge in water. Hold the sponge over a bucket of water and watch the sponge filter...

No comments yet! Be the first to add a comment below!

Please login to post comments.
After login, we will forward you back to this flashcard.


Upgrade and get a lot more done!
Upgrade    Cancel