Term
| How does the dialyzer function? |
|
Definition
| It allows for pt blood to interact with dialysate through a semipermiable membrane. |
|
|
Term
| What is one function of a dialysis delivery system? |
|
Definition
| To supply fresh dialysate and remove used dialysate. |
|
|
Term
| What are the components of the Delivery System? |
|
Definition
1.Blood Pump,
2.Ultrafiltration Pump,
3.Dialysate Conductivity Monitor,
4.Pressure guages,
5.Saftey Monitors,
6. Computerized Mechanisms. |
|
|
Term
| Generally speaking, what do healthy kidneys provide? |
|
Definition
| Kidneys provide a homeostasic enviroment, essential for cell survival, despite external conditions, health or illness. |
|
|
Term
| What is a "molecular weight cutoff"? |
|
Definition
| The maximum size or molecular weight that molecule can be and still pass through the membrane. This is also refered to as the Ultrafiltration Coefficient or the Clearance Rate. |
|
|
Term
|
Definition
| Compatible with biological functions. |
|
|
Term
|
Definition
| A life threatening allergic reaction. |
|
|
Term
| What are the two compartments of the dialyzer? |
|
Definition
| The blood compartment and the dialysate compartment. |
|
|
Term
| What type of membrane keeps the two compartments apart? |
|
Definition
| A semipermiable membrane. |
|
|
Term
| What is the typical condition of blood flowing through the blood compartment at the onset of treatment? |
|
Definition
| Blood, high in electrolytes, water and waste. |
|
|
Term
| What is the typical condition of the dialysate flowing through the dialysate compartment THROUGHOUT treatment? |
|
Definition
| A low level solution generally with low electrolytes counts and variable levels of sodium or glucose as perscribed by the pt's physician. |
|
|
Term
| What are the 5 factors that contribute to the effectiveness of a dialyzer? |
|
Definition
1. Membrane Biocompatibility,
2.Membrane Surface Area,
3.The Molecular Weight Cutoff,
4. The Rate of Solute Removal,
5. The Ultra Filtration Coefficient. |
|
|
Term
| What happens when blood comes in contact with a foreign substance? |
|
Definition
| Immune cells in the blood react to defend the body (complement activation). |
|
|
Term
| What are some symptoms of complement activation? |
|
Definition
| Blood clotting & severe allergic reactions. |
|
|
Term
| What type of dialyzer membrane may be best suited for use on dialysis patients? |
|
Definition
Synthetic dialyzers.
Scientific studies appear to indicate that synthetic dialyzers may decrease the severity of the complement response activated by the immune system. |
|
|
Term
| How is dialyzer biocompatibility tested? |
|
Definition
| Quantitative Blood tests, to check which types of proteins and how much of them were released into the bloodstream after a pt's blood made contact with the membrane of a dialzyer. |
|
|
Term
| What makes a membrane Biocompatible? |
|
Definition
| The membrane's ability to coat it's surface by adsorbing or binding certain blood proteins to it's walls. |
|
|
Term
| Why are reprocessed dialyzers more likely to be more biocompatible? |
|
Definition
| These dialyzers have residual protein coating its membrane walls, which prevent true blood contact with it's fiberin walls. |
|
|
Term
| What makes biocompatible dialyzers able to adsorb proteins? |
|
Definition
| Their hydrophobic qualities. |
|
|
Term
| What is the total surface area of most dialyzers? |
|
Definition
Between
0.5-2.4 square meters. |
|
|
Term
|
Definition
| The mass transfer coefficient. |
|
|
Term
|
Definition
| It refers to the permiablility of a dialyzer's pores at infinite supply. |
|
|
Term
| What is the relationship between the Molecular Weight Cutoff and the KoA of a Dialyzer? |
|
Definition
| Assuming that there is an infinate supply of blood and dialysate, the KoA refers to how easy it is for a particular solute to pass the membrane, but the molecular cutoff indicates the molecular size limitation of the largest molecule that would be able to get through the membrane. |
|
|
Term
| What is Molecular Weight? |
|
Definition
| The average total of weight of all the atoms making up a molecule, this generally equates to the "atomic mass". of the sum of all the atoms in a molecule. |
|
|
Term
| If a molecule is small, and another molecule is large, which molecule has the lower molecular weight? |
|
Definition
| Smaller molecules have less atoms than larger molecules, therefore the visibly smaller molecule weighs less. |
|
|
Term
| What unit of measurement is used to identify the weight of molecules in the field of dialysis care? |
|
Definition
|
|
Term
| What are the molecular weight cutoffs for dialyzers? |
|
Definition
3K-15K Daltons
(3,000-15,000 Da.)
|
|
|
Term
| What is the molecular weight of Albumin? |
|
Definition
|
|
Term
| What function does Albumin serve in the body? |
|
Definition
| Albumin, a blood serum protein is known as the molecular "taxi", serving as a carrier for molecules of low water soluability, like fat soluable hormones. |
|
|
Term
| Why is Albumin blood protein? |
|
Definition
In healthy pts, Albumin makes up nearly 60% of the blood plasma proteins. It
1. Binds to Calcium ions,
2. Acts as a blood pH buffer,
3. Prevents the degeneration of folic acid
,
4. Prevents edema by regulating the osmotic pressure in the blood by pulling water out of tissues and into the capillaries.
|
|
|
Term
| What is the molecular weight of Calcium (Ca+)? |
|
Definition
|
|
Term
| What function does Calcium serve in the body? |
|
Definition
Calcium is transported by albumin in the blood, and stored in teeth and bones.
It helps with blood clotting, affects nerve impulses, smooth muscle and the contractions of the heart.
It is refered to as an electrolyte and it carries it's own electrical charge. |
|
|
Term
| What is the molecular weight of Creatinine? |
|
Definition
|
|
Term
| What function does Creatinine serve in the body? |
|
Definition
| No significant function, it is chemical waste by product of creatine that is usually filered out of the blood through the kidneys. |
|
|
Term
| What happens when the kidneys no longer filter out creatinine? |
|
Definition
| Blood becomes toxic, pts may experience, fatigue, confusion, shortness of breath and dehydration. |
|
|
Term
| When the kidneys begin to leak albumin into the urine what does this mean? |
|
Definition
| As these proteins are big in size, they should not be able to pass to the urine through the tiny glomeruli within the kidneys, high levels of Albumin in the urine indicate severe kidney damage or failure. |
|
|
Term
| What is the normal level of creatinine in the blood? |
|
Definition
|
|
Term
| What blood creatinine level is too high? |
|
Definition
|
|
Term
| What is the molecular weight of Nitric Oxide (NO3)? |
|
Definition
|
|
Term
| What is the biologic function of NO3? |
|
Definition
| It contributes to vessel homeostasis. Low levels of nitric oxide gas molecules help to protect tissue from damage by acting as a chemical messenger between cells. Sustained high levels of NO gas in the blood contribute to vascular collapse or vasodillation or septic shock. It also helps in the immune and inflamation responce within the tissue. |
|
|
Term
What is the molecular weight of Phosphorus (PO24)? |
|
Definition
|
|
Term
| What is the biologic function of Phosphorus? |
|
Definition
In the bloodstream it is a charged ion that contains that is needed by the body to build and repair teeth and bones.
It assists with nerve function and helps muscles to contract. |
|
|
Term
| If phosphorus is not properly filtered out of the blood, what happens? |
|
Definition
As phophate levels rise, usually calcium levels drop.
High levels of phosphorus in the blood reduces the formation of Calcitriol, which in turn leads to a reduction in red blood cells, ultimately affecting blood ph, oxygen transport and how calcium is stored in bone. |
|
|
Term
| What is hyperphosphatemia? |
|
Definition
High phosphorus levels in the blood, lead to improper calcium transport and storage or the calcification of non skeletal tissues including the kidneys due to the lack of adequate red blood cells present in the blood. This condition leads to further organ damage.
|
|
|
Term
| What is the molecular weight of Urea? |
|
Definition
|
|
Term
| What is the biologic function of urea? |
|
Definition
| None. It is a metabolic waste by-product of protein breakdown. It is commonly refered to as Blood Urea Nitrogen or BUN. |
|
|
Term
| What is a normal BUN level for adults? |
|
Definition
7-20 mg/100mL
(miligrams per 100 mililiters of blood) |
|
|
Term
|
Definition
| A condition by which a person has abnormally high levels of urea in the blood. |
|
|
Term
| What does Azotemia cause? |
|
Definition
1. Shock,
2. Dehydration,
3. Gastrointestional Hemorrage,
4. An Irregular Heartrate. |
|
|
Term
| What is the molecular weight of Water? |
|
Definition
|
|
Term
| What is the biologic function of water? |
|
Definition
| It is essential for life and serves as the biological solvent. It is an effective medium for chemical reactions to take place in and helps support all biological functions of the human body. |
|
|
Term
What is TMP and what is it's unit of measurement?
|
|
Definition
Trans-membrane pressure.
It is the pressure difference across the membrane within the dialzyer.
Indicated as (mmHg) "milimeters of mercury" |
|
|
Term
|
Definition
Ultra-filtration rate.
It is rate at which excess fluid is removed from the blood due to the pressure ratios within the blood /dialysate compartments. |
|
|
Term
| What does the KUF on each dialyzer indicate? |
|
Definition
The manufacturer's ultrafiltration coefficient.
This is the amount of fluid that will pass through the membrane in ONE hour at a given pressure. |
|
|
Term
| What does the manufacturer's KUF on the label of each dialyzer help clinicians to determine? |
|
Definition
| The Ultrafiltration coefficient helps staff to predict how much fluid can be removed during a treatment. |
|
|
Term
| If a dialyzer's label indicates a KUF of 10, what does this mean? |
|
Definition
| This means that this particular dialyzer is capable of removing 10mL of excess water from the blood EACH HOUR for each unit (mm/Hg) of transmembrane pressure (TMP) present. |
|
|
Term
How much fluid could a pt loose in ONE HOUR from a dialyzer with a (KUF) of 10, and a TMP of 100.
|
|
Definition
| 10 mL x 100 mmHg = 1000 mL/Hg per hour |
|
|
Term
| What is the unit of measurement of KUF? |
|
Definition
mililiters per hour removed for each milimeter of mercury of pressure present.
mL/mmHg/hr |
|
|
Term
| What is the unit of measurement for TMP, trans membrane pressure? |
|
Definition
mmHg
milimeter of mercury pressure |
|
|
Term
| Let's say a dialyzer has a Kuf of 5 and a TMP set at 100, how much fluid could be removed in an hour? |
|
Definition
5mL (excess fluid) x 100 mmHg/hr( TMP pressure) =
500 mL of excess fluid per hour. |
|
|
Term
| How many Liters of water are in a kilogram? |
|
Definition
| 1 liter of water is equal to 1 kilogram of water. |
|
|
Term
| How many mililiters are in one kilogram? |
|
Definition
| 1,000 mililiters are in 1 kilogram. |
|
|
Term
| If 500ml are removed from a pt per hour, how many kilograms are being removed per hour? |
|
Definition
1mL= 1/1000 of a liter
500mL = 500/1000 of a liter or 1/2
1 liter = 1 kilogram, so
1/2 liter =1/2 kilogram
Answer: 0.5 kilograms per hour
|
|
|
Term
| How many mililiters are in a liter? |
|
Definition
| 1000 mililiters are in a liter. |
|
|
Term
| In order to remove 4 kg from a pt, how many liters of fluid need to be removed? |
|
Definition
If there are 4kg, and
1L = 1kg,
Then 4 liters would need to be removed.
(4000mL) |
|
|
Term
|
Definition
(K) refers to the clearance or how well a dialyzer can COMPLETELY remove certain solutes from the blood per minute of treatment.
It is expressed in mL of blood, at a given blood flow rate (Qb) at a given dialysate flow rate (Qd). |
|
|
Term
| Describe how blood flows through the dialyzer. |
|
Definition
As blood enters the top portion of the dialyzer into the blood compartment, and dialysate enters the bottom portion of the dialyzer thought the dialysate compartment.
This is called a countercurrent flow. |
|
|
Term
| Cellulose membranes of the dialyzer are primarily made from what organic material? |
|
Definition
Cotton.
Dialyzers with cellulose membranes have thin fiber walls and reduced surface area. |
|
|
Term
| Why are cellulose membranes the least biocompatible? |
|
Definition
| Cellulose dialyzers cause the most complement activation, and are least able to remove solutes by adsorbtion. |
|
|
Term
| How are modified cellulose membranes created? |
|
Definition
| The (OH-) Hydroxl groups are replaced with cellulose acetate, amino acids or synthetic molecules to increase adsorption efficiency. |
|
|
Term
| Name four synthetic dialyzer types. |
|
Definition
Polycarbonate,
polyacrylonitrile (PAN),
Polysulfone (PSF) and
Polymethymethacrylate (PMMA) |
|
|
Term
Which type of dialyzer has the thickest membrane wall?
|
|
Definition
|
|
Term
| What truely affects the clearance rates between synthetic and cellulose based dialyzers? |
|
Definition
| The Ultra Filtration Rate |
|
|
Term
If a dialyzer's label indicates for urea
K=250mL/min, Qb 300mL
What does this mean? |
|
Definition
K=250mL/min, Qb 300mL
This means, that in just one minute, 250mL of blood would be completely cleared of UREA by the dialyzer if the arterial pump is set at 300mL. |
|
|
Term
| What does Phosphorus K =300mL, Qb 350mL mean? |
|
Definition
| This means that the dialyzer can completely clear phosphorus from 300 mililiters of blood in just one minute, if the arterial pump is set at 350mL. |
|
|
Term
| How can a pts dialysis clearance if the Qb cannot be increased? |
|
Definition
| Select a better dialyzer with greater porosity, surface area and Kuf and then increase the Qd (dialysate flow) through the dialyzer. |
|
|
Term
| What is the purpose of dialysate? |
|
Definition
Dialysate is a solution that helps to remove uremic wastes, urea, creatine and excess electrolytes such as sodium and potassium from a pts blood.
It can also replace calcium and balance the PH of blood. |
|
|
Term
| In dialysis what does "osmolality" refer to? |
|
Definition
| The solute particle concentration of a solution. |
|
|
Term
Sometimes solutes are added to dialysate so that they can enter a pts blood.
What are they? |
|
Definition
| Sodium, bicarbonate, chloride & glucose. |
|
|
Term
| Who decides the osmolality of the dialysate solution? |
|
Definition
| A doctor prescribes the dialysate. |
|
|
Term
| What are the two types of dialysate? |
|
Definition
Acid concentrate
&
Bicarbonate Concentrate |
|
|
Term
| Describe the dialysate that is a acid concentrate. |
|
Definition
| It contains precise amounts of Sodium Chloride, Potassium Chloride, Glucose and Acetic Acid to lower the dialysate pH. |
|
|
Term
| Describe the dialysate that is a bicarbonate concentrate. |
|
Definition
| This dialysate solution has sodium bicarbonate, and sometimes sodium chloride. |
|
|
Term
| What happens with the two concentrations of dialysate? |
|
Definition
| Great care is taken to mix them at the right ratio into treated water to make the final dialysate solution. |
|
|
