Fresenius Medical Care 2008K Operator's Manual page 85

pressure and the pressure limits will be activated. If in the course of the treatment, as the venous
pressure increases, a clue to increasing viscosity from ultrafiltration, the alarm limits will be
automatically re-centered and then closed after one minute every 30 minutes during the treatment.
This is intended to keep the lower venous limit as tight as practical.
Increasing the blood pump rate will cause the alarm limits to spread in the appropriate direction
temporarily, i.e., a higher blood pump rate will increase the venous pressure.
Warning! The low venous pressure alarm may not occur with every disconnection or needle
dislodgement. Check all bloodlines for leaks after the treatment has started. Keep access sites
uncovered and monitored. Improper bloodline connections or needle dislodgements can result
in excessive blood loss, serious injury, and death. Machine alarms may not occur in every
blood loss situation.
Note: When the optical detector senses blood, the minimum the lower venous pressure limit
will be set to is + 9 mm Hg.
Transmembrane Pressure (TMP)
The transmembrane pressure (TMP) is equal to the venous pressure minus the dialysate pressure
measured in mm Hg. On the 2008K, the TMP is normally negative. Because the machine uses a
closed, volumetric ultrafiltration system, the TMP is monitored primarily for detecting large shifts
in pressure. In certain situations involving high-flux dialyzers, high blood-flow rate, or low UF
Warning! After starting dialysis, determine whether a stable TMP has been obtained and
whether it corresponds to the KUF of the dialyzer. TMP must be closely monitored with the
alarm limits. The TMP may not change substantially during UF errors when high permeable
dialyzers are in use. A fluctuating TMP, except in cases of single-needle dialysis, may indicate
2008K Operator's Manual rev. K
The venous pressure is represented in the same way as the arterial pressure, with
the pressure digitally displayed in mm Hg above a corresponding bar graph. In
the bar graph, under normal conditions, the pressure is represented by a green
horizontal bar between yellow bars representing the upper and lower alarm limits.
During alarm conditions, when the pressure rises or falls outside the alarm
window, the venous pressure bar changes from green to red. When alarm sounds
and the blood pump stops, venous line clamp closes, and a warning message
appears in the Status Box.
The alarm limits are set with a time delay for stabilization. Adjusting the blood
pump rate will cause the alarm limits to spread and stabilize before new limits are
established.
For 100 asymmetric limits, one minute after the alarm limits are centered the
lower limit will close to within 20 mm Hg to 35 mm Hg of the actual venous
rate, the TMP may approach 0 mm Hg.
After a time delay for stabilization, the alarm limits are automatically set at ±60
mm Hg for conventional dialyzers, and ±40 mm Hg for high flux dialyzers. The
alarm window automatically adapts for gradual increases in TMP caused by
increasing blood viscosity resulting from ultrafiltration.
Home Screen Monitoring
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