GE Corometrics 126, Service Manual

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Revision B 120 Series Maternal/Fetal Monitor 15-5
20155 90- 001
Troubleshooting: Fetal Pulse Oximetry Troubleshooting
Fetal Pulse Oximetry Troubleshooting
Table 15-4. Fetal Pulse Oximetry Troubleshooting
Problem Probable Cause Possible Solution
Displayed FSpO
2
does not correlate with
the SaO
2
value calculated from a fetal scalp
blood sample measurement on a blood gas
analyzer.
„
Close correlation requires simultaneous
blood sampling and pulse oximeter
measurements from the same arterial
supply. Blood samples exposed to air
during the sampling process may not
accurately reflect true arterial values.
„
The SaO
2
calculation may not have been
correctly adjusted for the effects of pH,
temperature, PaCO
2
, 2,3-DPG, or the
presence of fetal hemoglobin. In general,
calculated SaO
2
values are not as
reliable as direct CO-Oximeter or pulse
oximeter measurements.
„
120 F-Series accuracy can be affected
by incorrect sensor application or use,
significant levels of dysfunctional
hemoglobins, excessive patient
movement, venous pulsation, or nearby
electrosurgical interference.
„
Oxygen saturation greater than 85%
and/or pulse rate less than 100 could
indicate that the values are maternal in
origin.
„
Check whether calculations have been
corrected appropriately for relevant
variables. Refer to the equation in
“Principles of Operation” on page 6-6 of
the Corometrics 120 V3.5 Series
Operator’s Manual for more information.)
„
Observe all instructions, warnings, and
cautions in this manual and in the 120
Series Operator’s Manual.
„
Check sensor placement to ensure that it
is properly positioned on the fetus
Displayed FSpO
2
does not correlate with
the SaO
2
value calculated from a fetal scalp
blood sample measurement on a laboratory
CO-Oximeter.
„
Close correlation requires simultaneous
blood sampling and pulse oximeter
measurements from the same arterial
supply. Blood samples exposed to air
during the sampling process may not
accurately reflect true arterial values.
„
Fractional measurements may not have
been converted to functional
measurements before the comparison
was made. The 120 F-Series Monitor, as
well as other two-wavelength oximeters,
measures functional saturation.
Multi-wavelength oximeters measure
fractional saturation. Fractional
measurements must be converted to
functional measurements for
comparison.
„
Oxygen saturation values greater than
85% could indicate that the values are
maternal in origin.
„
Refer to the equation in “Principles of
Operation” on page 6-6 of the
Corometrics 120 V3.5 Series Operator’s
Manual for this conversion.
„
Check sensor placement to ensure that it
is properly positioned on the fetus.