-
Solutes with smaller molecular weight are dialyzable.
-
Diffusion
is the net directional movement of molecules occurring from a solution of higher
concentration to a solution of low concentration.
-
Ultrafiltration
is the movement of solvent across a semipermeable membrane in response to a
pressure difference applied across the membrane
-
If the solutes
dissolved in the solvent is small enough to permeate the membrane, they are
dragged along with the solvent and cross over to the other side, and this called
Convection.
-
Removal of urea from the patient is primarily due to existence of concentration
gradients.
-
High dialysate flow rates during hemodialysis maintain wide concentration
gradient.
-
Bicarbonate of dialysate bath correct the patients’ metabolic acidosis.
-
If air embolism is suspected, turn the patient on his left side and place the
patient in trendelenberg position
-
To prevent disequilibrium syndrome for a
patient with extremely elevated BUN, the first two hemodialysis treatment
should be less efficient.
-
Hemolysis is the major complication due to the
use of hypotonic dialysate.
-
TMP consists of positive pressure on the blood
side and negative pressure on the dialysate side.
-
Counter-current flow is used to maintain
optimum gradient between blood and dialysate cross the dialyzer membrane.
-
Factors influence the effectiveness of
diffusion during hemodialysis are: 1.Solute size
2.Permeability of the membrane 3.Dialysate flow rate
4.Dialysate temperature 5.Blood flow rate
6.Concentration gradient 7.Fluid removal
8.Clotting
-
Water solubility and small volume distribution
are characteristic of a drug allow it to be substantially removed by dialysis.
-
Access recirculation, decreased performance of
reused dialyzers, and presence of red blood cells and other plasma proteins
are possible factors for in vivo clearance being lower than in vitro
-
Dry weight, hours of dialysis, and KUF are
needed to calculate TMP
Ultrafiltration rate(ml/hr) = KUF X TMP
-
Dialysis machine assures the dialysate
entering the dialyzer is safe for the patient treatment by:
1. Regulate temperature
2. Regulate conductivity
3. Regulate PH
4. measure pressure and flow
5. Detect a blood leak 6.Alerts the user if
something wrong.
7. Bypass the dialyzer if dialysate is not
safe
-
The movement of water from an area of lower
solute concentration to an area of higher solute concentration is called
osmosis.
-
Potting soil, casing, fibers, and headers are
parts of a dialyzer
-
The volume of plasma cleared of a given
substance per unit of time is the definition of clearance.
-
Polysulfone, polyacrylonitrile and
polymtholmethacrylate are considered to be biocompatible dialyzers.
-
Dialyzer compliance is the increase in
dialyzer blood volume with increase in TMP.
-
Hollow fiber dialyzer has the least
compliance.
-
Needle size, needle position, stenosis, and
swelling are factors affect blood flow
- Types of
dialysate delivery systems are 1. Batch system, 2. Proportioning system 3.
Regenerative system.
-
Patients with acute renal failure,
cardiovascular problems and impaired liver function would tolerate
hemodialysis better if placed on bicarbonate dialysate bath.
-
Blood pressure, patient well being, and
evidence of dehydration or overload are the factors to consider when
establishing a dry weight for the patient.
-
The process by which a large amount of fluid
is removed at a rapid rate , with a little or no solute removal except by
convection is called isolated or pure ultrafiltration
- Charcoal
hemoperfusion is utilized to treat drug overdose the amount of solute leaving
the blood entering the dialysate / unit of time called Net flux.
-
Factors affect the clearance of the dialyzer
are blood flow, dialysate flow, temperature, effective surface area, and
concentration gradient.
-
The primary purpose of the proportioning pump
in a dialysate delivery system is to prepare the dialysate in proper water to
concentrate ratio.
-
Cherry pop appearance of the blood occurs in
the presence of hemolysis.
- Headache is an
early symptom of disequilibrium syndrome
-
Nausea, vomiting, headache and chest pain are
adverse effects of acetate dialysis.
-
A high venous pressure alarm may be caused by
needle placement, infiltration of the venous site, and clotting of the venous
return line.
-
Heavy meal during hemodialysis is discouraged
Factors affect the clearance of the dialyzer are blood flow, dialysate flow,
temperature, effective surface area, and concentration gradient.
-
The primary purpose of the proportioning pump
in a dialysate delivery system is to prepare the dialysate in proper water to
concentrate ratio.
-
Cherry pop appearance of the blood occurs in
the presence of hemolysis.
-
Nausea, vomiting, headache and chest pain are
adverse effects of acetate dialysis.
-
A high venous pressure alarm may be caused by
needle placement, infiltration of the venous site, and clotting of the venous
return line.
-
Factors affect the clearance of the dialyzer
are blood flow, dialysate flow, temperature, effective surface area, and
concentration gradient.
-
The primary purpose of the proportioning pump
in a dialysate delivery system is to prepare the dialysate in proper water to
concentrate ratio.
-
Cherry pop appearance of the blood occurs in
the presence of hemolysis.
-
Heavy meal during hemodialysis is discouraged
before or during dialysis to avoid, post dialysis hyperkalemia, postdialysis
hypernatremia, vomiting during dialysis, and hypotension during dialysis.
-
B12 is the marker for middle molecule
clearance.
-
Urea clearance is enhanced by high blood flow
rate and dialysate.
-
Nausea, vomiting, pericarditis, neuritis and
increase in urea and creatinine. Are symtopms and sighs of inadequate
dialysis.
-
KT/V more than 1.2 is the standard for
hemodialysis prescription to reduce the morbidity and mortality rate.
-
Movement of fluid from interstitial spaces to
vascular compartment occure as a result of hypertonic infusion therefore
should be avoided during the last hour of dialysis.
-
Regular use of high sodium dialysate ma
predispose to thirst, hypertension, and fluid overload.
-
Formula for Urea Reduction Ratio (URR) is:
Pre Urea - Post Urea /
Pre Urea X 100 = URR percent
[65% or more is the standard URR]
-
Molecular weight, blood flow rate, and
dialyzer are factors affect solute clearance.
-
The capability of a dialyzer to remove fluid
expressed as ml/hr/mmHg is called coefficient.
-
Pre-pump arterial pressure reading is
reflective of the resistance of the access to the blood flow out of access.
-
Hemolysis and vessel wall damages is great if
pre-pump arterial pressure is allowed to exceed >-250 mmHg.
-
A more negative arterial pressure reading is
suspected in an access with arterial stenosis.
-
Chest pain, shortness of breathing and
confusion during hemodialysis might indicate air embolism.
-
Appearance of cherry red blood, drop in Hct,
hypotension and chest pain are sighns of hemolysis.
-
Hemolysis can be avoided by checking
conductivity, pH, and temperature.
-
Number of hollow fibers in dialyzer
determines the its surface area.
-
Graft is a synthetic type of material placed
subcutaneously to join artery and a vein.
-
The correct angle to cannulate the fistula is
25-35 degree
-
The ideal time for maturation o AV fistula to
occur is 6-12 weeks.
-
Proper maturation of AVF is necessary to avoid
infiltration on cannulation and will enhance the life of the fistula.
-
Distance between venous and arterial needle
tips, presence of stenosis, and direction of the needle tips are factors
affect access circulation.
