Planned dialysis for ESRD is very different to dialysis for an
acute uremic emergency.
In ESRD access may have been planned and formed several
months previously, the patient is aware of the procedure
and in general the metabolic derangement of CRF will have
been progressing slowly.
A first chronic dialysis session may be performed as a
outpatient.
However correction of metabolic abnormalities in ESRD
can still have similar effect to that seen in HD for acute
uremia.
In ARF access will usually be temporary catheter, the
patient may be confused, catabolic, sick or just
frightened.
Factors to be considered include:
Length of session, Blood flow rate
Choice of dialyzer, Anticoagulation
Dialysate composition, Fluid removal
Skill of Technologist and presence of medical staff.
Anticoagualtion:
Heparin free dialysis is preferred for a first dialysis session, to
minimize the risk of pericardial bleeding, bleeding from access
sites, or intracerebral bleeding in the setting of hypertension.
Anticaogulation can be introduce subsequently.
Dialysis technologist and medical staff:
A first dialysis session required skilled staffing for monitoring
both the patient and equipment and for patient reassurance.
Complication may be severe or unexpected.
Length of dialysis:
A first dialysis should only reduce blood urea by 30 %
For most patient an optimum first session is about 60 -90 minutes.
Blood flow:
Usually about 150 – 200ml/mint for the first dialysis session.
Dialyzer:
High efficiency dialyzer ( koA >400) are not needed for the first
few dialysis session. If they are used, the length of session or
blood flow should be reduced.
Ultrafiltration:
No more than 2 liter should be removed during a first dialysis
session.
For patient with severe fluid overload – isolated uf
Bicarbonate
Preferred to acetate to minimize risk of hypotension.
Patients at severe risk of alkalemia may need reduced
bicarbonate concentration (<35mmol/l).
Sodium:
Avoid correction of hyponatremia too rapidly by altering the
dialysate sodium. In general 140-145 mmol/l is satisfactory.
Potassium:
Serum potassium will be reduce with correction of acidosis.
Use 4-4.5 mmol/l dialysate potassium.
Calcium:
Avoid low calcium dialysate as it may contribute to hypotension.
Dialysate flow:
Rate does not need altering (500 ml/mint)
General Reassessment:
Acute and chronic dialysis prescription should be reviewed,
evaluated and carried out accurately to obtain the
maximal efficiency for dialysis.
The patients physiologic status is assessed to ascertain the
necessity of adjusting any dialysis orders.
All machine parameters are assessed to ensure that the
prescribed procedure is correctly implemented.
The goal is to initiate and terminate the dialysis procedure
safely and comfortably with no or minimal complication.
Through rinsing of the dialyzer is important because it may
reduce the incidence or severity of anaphylactic dialyzer
reaction by virtue of removal of leachable allergens.
Micro bubbles are removed when the venous end of the
dialyzer pointed upward.
The dialyzer should be used within 5-10 minutes to avoid
leaching of residual ethylene oxide or other leachable
allergens into the rinsing fluid.
Dialyzer should be rerinsed briefly immediately prior to
dialysis if more than 10 minutes ha elapsed.
Weight, pulse rate, B.P laying and standing temperature, fluid
status, blood investigation and vascular access patency and
freedom from infection.
Obtaining Vascular access:
Poor vascular access is a limiting factor to patient survival on
hemodialysis.
Therefore great care must be taken to maintian adequate vascular
access.
Percutaneous venous cannula ( femoral, subclavian and jugular)
Residual heparin or clot is first aspirated from both catheter
lumen.
Check the patency of each lumen by irrigating with a saline filled
syringe.
Heparin loading dose is administered in the venous limb and
flushed with saline
Initiate dialysis after 3 minutes.
AVF and graft using permanent vascular access
Set the blood flow rate at 50-100 ml/min, until the blood fills
the blood circuit.
The priming fluid in the lines and dialyzer is disposed of to
drain until the blood reaches the venous air trap.
in unstable patient the priming fluid is usually given to the
patient maintain the blood volume.
Increase the blood flow rate to the desired level after the
circuit is filled with blood (150-250 in acute cases)
Initiate the dialysis solution flow and adjust the TMP.
Alarms:
Blood circuit alarm and dialysis solution circuit alarms
Patient monitoring during dialysis
Pulse rate, BP every 30 to 60 minutes in chronic dialysis, but at
least every 15 minute in acute dialysis
Food and fluid intake, complication during dialysis and
particular observation.
Termination of dialysis
Saline rinse:
The blood is returned by pumping sterile normal saline into the
arterial side until the blood is displaced.
After the bubble trap the fluid should be very pale pink in color
( to assure that the patient has lost the least of red cell)
Saline air rinse:
The blood is forced by pumping a small amount of saline into
the arterial line, then the line is opened to allow air into the
circuit to push the saline and blood.
Again the fluid entering the patient should be very pale pink in
color.
Patient monitoring post dialysis:
Weight, pulse rate, BP laying and standing, Temperature, blood
investigation and vascular access patency.
All patient parameters and any unusual occurrences should be
documented on patient file.
Equipment care:
The of dialysis machine is the responsibility of the staff and of
the biomedical technicians.
Scheduled maintenance recommended by the manufacturer
should followed meticulously for the safe and efficient
function of the equipment.