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CCHT Exam
Concepts & Study Material of the Hemodialysis Core Curriculum Module II
68
Health Care
Professional
03/30/2011

Additional Health Care Flashcards

 


 

Cards

Term
What are the 3 Scientific prinicples on which dialysis is based?
Definition
Osmosis, Diffusion, & Ultrafiltration.
Term
What are the 3 main kidney functions that Dialysis treatments replace?
Definition

1. Removal of excess fluids from Blood.


2. Removal of excess waste in Blood.


3. Balancing of Electrolytes in the Bloodstream.

Term
Which main function does the dialysis fail to replace?
Definition
Endocrine function.
Term
What is an endocrine function?
Definition
A hormonal function.
Term
What are the four hormones that healthy kidneys secrete into the bloodstream?
Definition

1. Rennin

2. Calcitriol

3. Erythropoietin

4. Thrombopoietin

Term
Why is it important to understand the endocrine function of the kidney?
Definition
It is neccessary to understand the full impact the kidneys have on the body.
Term
What is a hormone?
Definition
A chemical messenger.
Term

Of the four hormones secreted by healthy kidneys, what is the function of:

Rennin

Definition
Rennin regulates proper pressure. Rennin breaks down certain blood serum proteins that are responsible for arterial wall constriction.
Term

Of the four hormones excreted by the kidneys, what is the role of:

 

Erythropoietin

Definition
Erythropoietin regulates the transfer of oxygen and nutrients throughout the blood by increasing the production of healthy red blood cells in the bone marrow.
Term

Of the four hormones excreted by the kidneys, what is the primary role of:

 

Thrombopoietin

Definition
TPO, or thrombopoeitin, is responsible for stimulating the production of blood platelets, which aids in the clotting response.
Term

Of the four hormones excreted by the kidneys, what is the function of:

 

Calcitriol

Definition
Calcitriol is a byproduct produced by the kidneys when Vitamin D is present in the bloodstream.  It is known as Vitamin D3, and it helps the body to absorb Calcium.
Term
What is a solution?
Definition
A mixture of solvent and solute.
Term
What is a solute?
Definition
The disolvable substance.
Term
What is a Solvent?
Definition
The substance that disolves the solute.
Term
Why is water considered the universal solvent?
Definition
Because over time, Water can disolve or errode almost all matter.
Term
Identify the components of dialysate.
Definition

Solvent & Solute

By which treated water contains proportioned amounts of dissolved
   Salt Ions (Electrolytes) and sometimes glucose.

Term

Pt blood electrolyte levels can be controlled by changing what during dialysis?

Definition

The dialysate composition. 


Adding electrolytes to the dialysate at a concentration higher than the pts blood will cause a concentration gradient, and electrolytes will enter the pt blood until an equilibrium is reached during treatment.

Term
Define semipermiable membrane?
Definition
A pourous barrier that only permits certain sized molecules to pass.
Term
Define surface area?
Definition
The total pourous area of the membrane, allowing for passive or active transport of molecules across the membrane.
Term
Diffusion utilizes which type of transport?
Definition
Passive Transport
Term
Which molecules are usually prevented from passage through the semipermiable membrane of the dialyzer?
Definition
WBC, RBC, some Viruses, and Proteins.
Term
Which molecules are small enough to pass through the semipermiable membrane?
Definition
Urea, Water, and Electrolytes, Bicarbonate Solution.
Term

Define diffusion.

Definition
Process by which atoms, molecules or particles move from areas of high concentration to areas of lower concentration.
Term
Diffusion can occur in which states of matter?
Definition
Gas, Liquids and Solids.
Term
Explain how blood is a solution.
Definition
Blood plasma is the solvent, and the solutes disolved by the plasma are electrolytes and  other substances. Particulate matter are proteins and WBC, RBC which do not disolve, yet remain suspended in the Blood plasma.
Term
Passive transport into and out of the body's cellular membranes occurs by which two processes?
Definition
Osmosis and Diffussion
Term
Which direction do solutes move across the membrane?
Definition
They can move in any direction, but always move from areas of high concentration to areas of lesser concentrations.
Term
Passive Solute movement naturally increases when?
Definition
The concentration gradient of the solute increases.
Term
Theoretically, when does diffusion stop?
Definition
When there is no loger a concentration gradient.
Term
How is dialysate is able to remove wastes from blood serum?
Definition
By means of concentration gradients.
Term
How does molecular weight influence particle movement?
Definition
Larger dissolved particles diffuse slowly and with some difficulty. Smaller molecules/dissolved particles diffuse more easily and quickly.
Term
What are examples of blood components that are difficult to diffuse accross the semipermiable membrane of a dializer?
Definition

White blood cells,

Red Blood Cells,

Albumin,

Blood Platelets,

Some Bacteria &Viruses.

Term
How does temperature affect diffussion?
Definition
Molecules move faster at increased temperatures, therefore warmer fluids permit faster diffussion.
Term
What are the factors that affect diffusion?
Definition
 Temperature, molecule size, surface area, flow geometry and membrane permeability.
Term
How does a dialyzer's surface area affect diffusion?
Definition
Greater surface areas usually lead to more pores, and a membrane with more pores allows for faster diffussion of the smaller molecules.
Term
How does the "countercurrent" flow between dialysate and blood aid diffusion?
Definition
It maintains the highest concentration gradients between the blood and dialysate possible, thus promoting the rapid removal of waste matter and ease of electrolyte transfer from one side of the membrane to the other.
Term
What is the main diffrence between Osmosis and Diffusion?
Definition
In diffusion, solutes move.  In osmosis, the solvent moves across a membrane.
Term
Define osmosis.
Definition
Osmosis is when the solvent moves across a membrane from an area of low solute concentration towards the area of higher solute concentration.
Term
Define an osmotic pressure gradient.
Definition
The difference in concentrations of solute within a solution on either side of a membrane.
Term
When does osmosis and diffussion stop?
Definition
When an equilibrium is reached on both sides of the membrane.
Term
What is a natural example of hydraulic pressure that can overcome osmotic pressure?
Definition

Gravity.

This is one reason the dialzyer is flipped leaving the arterial side up.

Term
How is ultrafiltration accomplished in the dialzyer?
Definition
Additional pressure is created by gravity, as wells as high pressure gradients across the membrane.  These pressure differences force high concentrations of molecules across the membrane into the dialysate faster.
Term
 Which type of heat transfer causes solute drag?
Definition

Convection.

Convection causes a solvent to drag along smaller solutes when heat is present in the solution as the solvent crosses the membrane during the process of osmosis.

Term
What forces affect the movement of fluid through the tubing of the extracorporeal circuit?
Definition
Resistance (pressure/constriction), flow rate (volume) and velocity (speed).
Term
How is flow rate measured in dialysis?
Definition
 Mililiters (mL) of fluid flowing per minute (min) measured ( mL/min).
Term
What is flow velocity?
Definition
The speed that a fluid flows.
Term
What is the relationship between flow and resistance in a fluid system?
Definition
The greater the flow, and the greater the resistance, the greater the pressure will be.
Term
Name the three cell compartments in the body.
Definition
Intracellular, Interstitial & Intravascular.
Term
Define Intracellular.
Definition
Inside the cell.
Term
 Define Interstitial.
Definition
Between the cells.
Term
Define Intravascular.
Definition
Inside the vessels or vascular system.
Term
During dialysis, from which body compartment is water primarily removed?
Definition
The vascular compartment.
Term
What does the extracorporeal circuit consists of?
Definition
The dialyzer and the tubing.
Term
Identify the two restriction points in the extracorporeal circuit.
Definition
The arterial needle insertion and the veneus neele insertion points.
Term
Why is the arterial insertion point a sourse of resistance?
Definition
 Because at this restriction point, the arterial pump is pulling blood from the body faster than the source can naturally release it, causing a NEGATIVE PRESSURE (below zero).
Term
Positive pressue is converted from negative pressure inside the tubing within the arterial blood pump. As this positive pressure increases in the lines where does it reaches its highest point?
Definition
At the Arterial header, where blood enters the dialyzer fibers.
Term
There is little resistence in the blood compartment why?
Definition
Blood is following from the arterial header into the dialzyer, towards the pull of gravity, so there is little resistance.
Term
Where is the lowest point of positive pressure?
Definition
The veneous pressure, measured as blood leaves the blood compartment of the dialyzer.
Term
How is hydraulic pressure, created by gravity is calculated?
Definition
By averaging the blood entering and leaving the dialzyer fibers.
Term
Explain how gravity overcomes osmotic pressure during ultrafiltration (UF).
Definition

The force of gravity is the true hydraulic pressure that overcomes osmotic pressure within the dializer, because it is greater in force, thus aiding in UF, by forcing fluid out of the blood,through the membrane,and into the dialysate.

Term
How does dialysis affect the intracellular compartments in the body during the course of a treatment?
Definition
Diffusion occurs continuously in the pts body. As cleansed blood is returned to the intravascular system, it dillutes the existing blood, and creates a new concentration gradient. As the intracellular wastes are exposed to this new concentration gradient, the wastes within the cells are drawn out and are released into the interstitial space where they are in turn deposited into the intravascular system to be processed through the extracorporeal circult where they are in turn dialyzed.
Term
What is EDW?
Definition
Estimated Dry Weight.
Term
What is a SC?
Definition

 Sieving Coefficent.

It is a measure of porosity. During convective transport both the size and number of holes in the dialyzer membrane will determine how porous it's membrane actually is.

Term
What does SC value of  1.0 mean?
Definition
This means that under ideal circumstances, 100% of a given solute (disolvable particulate matter or disolved molecules) could pass through the membrane.
Term
What does a SC value of 0 .4 mean?
Definition
This means that under ideal circumstances, only 40% of a given solute could pass through the membrane, and the other 60% would remain in the pts bloodstream.
Term
What happens if the intracellular regions of the body have high levels of toxic solutes?
Definition
Water is pulled out of the blood and into the cells causing edema.
Term
How is edema treated during dialysis?
Definition
Sodium is added to dialysate at a greater concentration than the blood, so it is permitted to enter the bloodstream.  Once in the bloodstream, water is drawn out of the cells, in an attempt to dillute the blood sodium levels, this blood is dialyzed, and the water in it is removed.  Near the end of treatment, the sodium level in the dialysate is reduced so that it is removed from the bloodstream safely.
Term
How does a saline bolus help a pt with low blood pressure?
Definition
Saline once in the blood system causes the fluid within the cells to be drawn out and into the bloodstream, thus increasing the blood volume and pressure on the vascular walls.  Increased blood volume typically increases the blood pressure.
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