Fresenius Medical Care 2008K Operator's Manual page 108

Chapter 4—Monitoring the Treatment
In cases of unsatisfactory Kt/V, the operator should check:

For proper needle placement and connections to the bloodlines.

That the machine is set for prescribed blood flow rate.

That the proper dialyzer is being used.

That the dialysate flow rate is as prescribed.

That the blood and dialysate lines are properly connected to the dialyzer so that the
blood and dialysate flow are countercurrent (blood flow down, dialysate flow up).

If the preceding is correct, check the patient's access flow rate (fistula or graft).
A substandard Kt/V could also indicate a problem with clotting, recirculation within the
patient's access, or other problems.
While a treatment is in progress, the Kt/V may be increased by increasing the flow rate of the
blood pump or increasing the dialysate flow rate. Changes to the prescribed treatment
parameters, however, should be consistent with a physician's orders.
Note: The OLC self test should be run occasionally (1 – 2 times per month) or any time that
you suspect that the OLC results may be erroneous
Access Flow
How Access Flow is Derived
In order to determine the patient's access flow rate (AF), two OLC tests are done, one with
the bloodlines connected in the normal position and one in the reversed position. In the
reversed position, recirculation is induced. The higher the patient's access flow rate, the
lower the recirculation. With the two OLC tests, the access flow rate can be calculated. The
measurement is more accurate at lower access flow rates. Because it may be difficult to
obtain high blood flow rates with the bloodlines in the reversed position, it may be necessary
to reduce the blood flow rate for both tests. The result will be more accurate if both tests are
done at the same blood flow rate.
Note: Fresenius Medical Care recommends using Combiset bloodlines with Twister blood
flow reversal device (P/N 03-2794-0) for treatments running access flow tests. The
integrated Twister device eliminates the need to disconnect the bloodlines from the access
during treatment. All blood flow direction changes are done aseptically within the Twister
device.
108 2008K Hemodialysis Machine Operator's Manual Rev P