GE Corometrics 250cx Series, Service Manual, Page: 72 / 252

3-18 250cx Series Maternal/Fetal Monitor Revision C
2036947-001
Installation: Service Mode Screens
FECG Artifact Elimination
This field is used to enable/disable FECG Artifact Elimination which affects
only the direct FECG mode. Use the Trim Knob to alternate between On
and Off . (The factory default setting is Off .) When On is selected, any new
heart rate value which differs by more than ±25 bpm from the previously
calculated heart rate is not printed on the strip chart paper. When
Off is
selected, all heart rate values are printed on the strip chart paper
without regard to previous rates.
Theory and Methodology
When FECG artifact elimination is turned on , the monitor does not print any new
FHR value which differs by more than ±25 BPM from the previously calculated
heart rate value. The printing inhibition functions on a beat-to-beat basis by
comparing the last calculated rate against the newly calculated rate. The rate used
for comparison purposes is always the previous rate regardless of whether this rate
passed the previous ±25 BPM test. When FECG artifact elimination is turned
off , the
direct FECG rate is plotted by the recorder without regard to its deviation from the
previous rate. The effect of this function change is that sudden heart rate changes
(such as certain arrhythmias, accelerations or decelerations) as well as artifactual
changes (as when the electrode is disturbed or loosely connected) are recorded when
FECG artifact elimination is turned
off . They are not recorded when FECG artifact
elimination is turned on ; instead gaps (pen lift) in the tracing occur.
Default TOCO Reference
This field sets the default uterine activity pressure reference for the tocotransducer.
Use the Trim Knob control to cycle through the available settings:
5, 10, 15, 20,
or 25
relative units in mmHg mode or
0.7, 1.3, 2.0, 2.7,
or 3.3 in kPa mode. (The factory
default setting is 10 in mmHg mode or 1.3 in kPa mode.)
When using a tocotransducer, momentary depression of the
UA Reference
button sets
the pressure baseline at the default setting.
Pressing the
UA Reference
button for more than 2 seconds causes the UA reference
value to override the default setting and cycle through all available selections:
5, 10,
15, 20,
or 25 relative units in mmHg mode or
0.7, 1.3, 2.0, 2.7,
or 3.3 in kPa mode,
starting at the default setting until the button is released. This value is stored as the
new baseline for the currently measured uterine activity signal; as soon as the
UA
Reference
button is momentarily pressed, the baseline returns to the default value.
Smart BP
The 250cx Series has a
Smart BP
feature that prevents an automatic blood pressure
determination from occurring during a uterine contraction.
This feature:
„ reduces the chances for erroneous vital signs readings; and
„
reduces patient discomfort during labor.
1
The MSp0
2
trend is plotted over a range of 60-100% on paper with a HR scale of 30-240 bpm. The MSp0
2
trend is
plotted over a range of 50-100% on paper with a HR scale of 50-210 bpm.