HCEN12630 Revision 07.2015
Program version 1.xx
AK 98™ Dialysis Machine - Technical description 85
3.3.3.6.11 Diascan
®
- Conductivity cell C (option)
The Diascan system can be used for:
● Clearance measurement (K) in order to read the current dialysis efficiency for the
on going treatment
● Dialysis dose measurement (Kt or Kt/V) in order to check that the prescribed
dialysis dose is being maintained, which provides quality assurance for the
treatments.
● Kt/V target supervision , which means that the machine constantly calculates if
the desired and minimum values for Kt/V, set by the operator for each individual
patient, can be reached at treatment end. If not, the operator will immediately be
notified during treatment.
If Kt/V measurement is required, a distribution volume VOLUME has to be set
before the measurement check takes place. The distribution volume is
patient-related (based on the patients dry weight) and has to be properly
calculated and set by the operator in order to obtain a correct Kt/V value.
Hardware
The hardware is an extra conductivity cell. The conductivity cell is used to measure the
conductivity after the dialyzer. The Diascan cell has a temperature sensor, PT-100, for
temperature compensation of the conductivity value. The temperature can not be
logged like the other temperature transducers, since the conductivity value is
compensated for temperature already in the cell. The cell cannot be calibrated in the
field.
The Diascan cell is offset, to match the P cell, as the UF cell is performing taration.
The reason for the offset is the fact that the cell is after the dialyzer. This means that it
is affected by the biofilm and hence the offset.
Figure 3-24. Conductivity.
1. Conductivity P
2. Conductivity Diascan cell
3. Conductivity cell P
4. Diascan cell
Function
The Diascan cell measures the effectiveness of the treatment or the K. K for clearance
or how many mL/min of blood that has been cleared from urea. However the machine
cannot measure urea. But the machine can measure sodium ions. Sodium ions has
about the same size as urea.
The idea is to calculate the clearance of sodium or how the transport of sodium is done
over the membrane. The calculation also takes in consideration things that decrease
the transport capacity like the actual blood flow, fluid flow, clotting, fistula recirculation
and many other factors by increasing/decreasing the sodium level in a step of 0.5
mS/cm for about 5-7 minutes and then measure the conductivity before and after the
dialyzer, the ability of the dialyzer to transport sodium can be calculated. Depending on
To Next Page
Loading...
Need help?
General
