GE Corometrics 250cx Series, Operator'S Manual

Page: 79 / 250

Revision C 250cx Series Maternal/Fetal Monitor 6-3
2036946-001
Uterine Activity Monitoring: Tocotransducer (External Method)
Tocotransducer (External Method)
NOTE:
Refer to the “Maternal/Fetal Monitoring, Clinical Applications Manual”
for patient application information.
Methodology
A tocotransducer applied to the maternal abdomen records relative changes in
abdominal tension caused by uterine contractions. The mode (
TOCO
) and value are
shown in the
UA
area of the display. During normal operation, the UA value displays
from
0–100
in mmHg mode and 0.0 - 13.3 in kPa mode. Uterine activity is
continuously plotted on the bottom (or right) grid of the strip chart paper as a plain
black line.
IMPORTANT:
FOR TRIMLINE TOCOTRANSDUCERS ONLY—You must wait
at least 10 seconds from the time you power the monitor on or
connect a tocotransducer before pressing the
UA Reference
button.
Establishing a Baseline
Monitoring uterine activity using a tocotransducer provides relative pressure
measurements—compared to a baseline or UA reference. The quality of
measurements depends on the following:
„
position of the tocotransducer;
„ belt tension;
„
size of the patient; and
„ established baseline.
All 250cx Series Monitors provide a
UA Reference
button that sets the baseline. When
a baseline is established, all pressure measurements are relative to that baseline. The
baseline can be set manually by two different methods or automatically, when
necessary. Whenever the baseline is set, the bottom line of the bottom strip chart
grid is annotated with
UA REF.
Initial Referencing
The initial reference occurs automatically. After you plug in a transducer, verify that
the display reads less than 30 mmHg (4 kPa). Make a note of the reading.
The purpose of establishing a baseline at this point is necessary for consistency
when applying and tightening the belt. You will have to set the baseline again, after
tightening the belt.