Module 4 Hemodialysis Devices
Dialyzer's real clearance can differ from the manufacture by how much?
-/+ 10-30 percent
What are the flow rates for dialysate?
0-1,000 ml/min
Glucose range
0-250 Normal blood glucose levels are 70-105
Sodium (Na) range
135-145
Cellulose membranes has a size molecules limit what is it?
3,000 Da
What is the range of molecular weight cutoffs for dialyzers?
3,000 to more than 15,000 Da
Phosphorus (PO4)
3.5 - 5.5
Potassium (K) range
3.5 - 5.5
What is the normal potassium level?
3.5-5.5
What is the temp range for dialysate?
37c to 38c 98.6f to 100.4f
What is the ph range for dialysate?
7.0-7.4
What is the normal range of ph of blood?
7.35-7.45
Calcium (Ca) range
8.5 - 10
What is dialysate?
A blend of treated water and chemicals, it removes waste and fluid and balances electrolytes
What is bicarbonate?
A buffer, a substance that tends to maintain a constant Ph in a solution
Describe the dialyzer design?
A clear plastic cylinder Inside thousand of fiber tubes as thin as strand of hair.
What is Volumetric control?
A machine that uses two chambers that fill and drain to control the volume of dialysate going to and coming from the dialyzer
What is PH?
A measurement of how acidic or alkaline a solution is
What is the proportioning system?
A type of dialysate delivery system
What are the two solutions that the dialysate starts out with?
Acid Bicarbonate
What ph is less than 7.0?
Acid ions, acidic
What has a ph higher than 7.0?
Alkaline
What is flow rate?
Amount of fluid that flows through the tubing in a given period of time
What has the Ph of 7.0?
Base or neutral
What are the characteristics of a dialyzer?
Biocompatibility Membrane surface area Molecular weight cutoff UF coefficient and clearance
What does the diffusion rate depend on?
Blood and dialysate rates Membrane surface area and thickness, number of pores Solution temperature Membrane resistance Concentration of gradient Size, weight, and change of solutes
How does the dialyzer work?
Blood enter the dialyzer at the top flows through each fiber, and leaves through the bottom Dialysate flows around the fibers in the opposite direction, in a counter current flow.
Modern, high-tech delivery system includes what?
Blood pump Ultrafiltration pump Dialysate conductivity monitor Alarms Pressure gauges
When a blood leak occurs what happens?
Blood pump stops, the venus line clamps to prevent further blood loss Bypass shunts dialysate to the drain
What does too hot dialysate cause?
Bursting of red blood cells (hemlysis)
How is the flow rate controlled?
By the flow pump
Glucose abbreviation
C6H12O6
What is the abbreviation for chloride?
CI
What can dialysate replace?
Calcium Bicarbonate
What does the dialysate delivery system control?
Controls amounts water and chemical in dialysate Conductivity Temperature ph Flow rate Pressure
What are cellulose membranes made from?
Cotton based material that is spun into hollow fibers
What is the abbreviation of Daltons?
Da
What two systems is the delivery system?
Dialysate Extracorporeal blood circuit
Calcium range
Dialysate 2.5-3.5 Normal 8.5-10.5
What is sodium modeling.
Dialysate delivery systems can Djust the dialysate sodium level according to the doctors prescription
Chloride ranges
Dialysate range 100-124 Normal plasma range 98-111
Why is th.e surface are key to how well a dialyzer can remove solutes?
Dialyzer with more surface area can expose more blood to dialysate
What are the 3 main ways to remove solutes?
Diffusion Convection Absorption
Bicarbonate (HCO3) range
HCO3
Bicarbonate abbreviation
HCO3
What is metabolic acidosis?
Having too much acid in the blood
Hyponatremia symptoms
Headache Faintness Confusion Muscle cramping Nausea/vomiting Abdominal cramps Convulsions
What are the characteristics of the synthetic membrane?
Highly absorptive They have the thickest fiber walls, 30-55 microns Solutes are removed by convection, diffusion, and absorption Removing of solutes up to 15,000 Da Biocompatibility is very good
What is conductivity?
How much electricity the fluid will conduct
Biocompatibility
How much membrane is compatible with the human body
Synthetic fibers are?
Hydrophobic (water repelling)
What can bicarbonate reduce in a pt?
Hypotension Muscle cramps Nausea Fatique
Where is Magnesium found?
In the plasma at levels 1.4-2.1 Range in dialysate is .05-1.0
What fluid is potassium a major electrolyte?
Intercellular fluid
What does calcium(Ca) do?
It builds bones and teeth, helps muscles move, is needed for blood clotting and helps send nerve signals
Hyperphosphatemia symptoms
Itching
Potassium abbreviation
K
What is the abbreviation for clearance?
K
What is the abbreviation of Ultrafiltration Coefficient?
KUF
What is the abbreviation for Mass Transfer Coefficient?
KoA
What is low conductivity?
Lack of concentrate in one or both of the concentrate jugs
What are the characteristics of the cellulose membrane?
Least biocompatibility Cause the most complement activation Least able to remove so,Utes by adsorption
What is the purpose of a dialyzer?
Let's the patient's blood interact with dialysate through a semipermeable membrane
What does the blood leak detector do?
Let's you know when there is a tear in the membrane of the dialyzer letting the blood and dialysate mix
How does the membrane act?
Like a vessel wall of a human nephron, the membrane allows only certain solutes and water to pass through
What does to cold dialysate cause?
Makes the pt cold Reduces diffusion
What is adsorption?
Material that sticks to the dialyzer membrane
What is UF control systems?
Means by which dialysis machine removes fluid from the pt and accurately measures it
What factors affect removal of solutes and fluids during dialysis?
Membrane material Characteristics of each dialyzer
Adsorptive ability depends on what three things?
Membrane material Surface area How much material has already Adsorbed to the membrane
What are the keys to the dialyzer's ability to adsorbed?
Membrane material Surface area How much material has already adsorbed to the membrane
Magnesium abbreviation
Mg
What is the purpose of hemodialysis delivery system?
Mixes and delivers dialysate Pumps blood through the dialyzer Monitors various dialysis parameter Ensures a safe treatment
What is the proportioning system do?
Mixes liquid concentrate with measured amounts of treated water to form dialysate and delivers it to the dialyzer
What is diffusion?
Movement of solutes across a semipermeable membrane from a greater concentration to a lower concentration.
What does the modified cellulose membranes have new?
Much thicker walls Remove solutes up to 15,000 Da Biocompatibility ranges for good to very good
Hyperkalemia symptoms
Muscle weakness, numbness and tingling, cardiac arrest
Sodium abbreviation
Na
Arterial pressure is positive or negative?
Negative
Adsorption
Occurs when material sticks to the dialyzer membrane
Calcium is found where in the body?
Outside of the cells (extracellular) Inside the cells (intracellular fluid)
How is conductivity checked?
Placing a pair of electrodes in the dialysate voltage is applied to the electrodes and the current is measured.
Synthetic membrane characteristics
Polymers formed into hallow fibers Solutes removed by convection, diffusion, and adsorption Clearance depends on UFR Highly Adsorptive, good at keeping blood from touching the membrane
What are the synthetic membranes made of?
Polymers that are formed into hollow fibers
What is high conductivity?
Poor water flow to the proportioning system Untreated incoming water Use of the wrong dialysate concentrate
What is the acid concentration?
Precise amounts of the following: Sodium Potassium Magnesium Calclium Glucose Acetic acid
Blood flow rate abbreviation?
Qb
Dialysate flow rate abbreviation?
Qd
When is glucose added?
Reduce muscle break down Add calories who are diabetic or malnourished
Potassium functions
Regulates fluid, ion balance inside cells
Explain Ultrafiltration in dialysis
Remove water from pt's blood Dialysis machine creates hydraulic pressure that squeezes water out into the dialysate
What is ultrafiltration?
Removing excess fluid
What is the bicarbonate concentration?
Sodium bicarbonate Some cases sodium chloride
Which dialyzer is more biocompatible, synthetic or cellulose membranes?
Synthetic membranes They are more water repelling which allows them to absorb blood proteins
What is the abbreviation for Transmembrane Pressure?
TMP
What is Mass Transfer Coefficient (KoA)?
The ability of a solute to pass through the pores of a dialyzer
What is clearance?
The amount of blood that can be cleared of a solute in a given period of time
What is ultrafiltration coefficient?
The amount of fluid that will pass through the membrane in one hour, at a given pressure
What is bypass?
The circuit stops the flow of dialysate to the dialyzer and shunts it to the drain
What does molecular weight cut off mean?
The determination of the largest molecule that can pass through the membrane
What is transmembrane pressure (TMP)?
The difference between these pressures, blood side CDs dialysate (gradient)
Sodium (Na)
The major electrolyte of the. Odds blood plasma and interstitial fluid(between the cells) It causes fluid to move across cell membranes Normal concentration in blood is 135-145
What it the key to biocompatibility?
The membranes ability to absorb proteins into the fiber wall
Magnesium is important to what?
The nerves and muscles
What is transmembrane pressure (TMP)?
The pressure difference across the membrane (blood compartment pressure, minus dialysate compartment pressure)
What are some symptoms of high sodium (hyper atresia) issues?
Thirst Flushed skin Dry mucus membranes Tachycardia Seizures
Sodium modeling can create what symptoms?
Thirst Hypertension Body weight
What is the most vital monitors of patient safety?
Trained staff who knows dialysis principles, equipment and procedures
What is UF? How does it work?
Ultrafiltration UF is a way to remove excess water from pt during hemodialysis by applying pressure
What is UFR?
Ultrafiltration rate
What does dialysate help remove?
Uremic waste (urea/creatinine) Excess electrolytes (sodium/potassium)
Osmotic
Water pulling
What is convection? What is another word (term) for convection?
When fluid crosses a semipermeable membrane, some solutes aware pulled along with it. Solvent drag
When does UF occur during treatment?
When the pressure on the blood side of the dialyzer membrane is more positive than the dialysate side
Are reuse dialyzer more biocompatibility?
Yes
What is the best way to remove small/low molecular weight solutes?
diffusion
