GE Corometrics 250cx Series, Operator'S Manual

Page: 89 / 250

Revision C 250cx Series Maternal/Fetal Monitor 7-7
2036946-001
Maternal Heart/Pulse Rate Monitoring: Maternal ECG Monitoring
Maternal ECG Monitoring
Theory and Methodology
The maternal heart rate (MHR) is measured via electrodes placed on the maternal
chest. When MECG is employed, the maternal heart rate is computed on a beat-to-
beat basis using the R-to-R time interval on the maternal QRS complex. When
MECG is selected as the MHR/P source, the MHR is displayed on the front panel
display in beats per minutes (bpm), denoted by
MECG
. The heartbeat indicator
flashes for each detected heartbeat. The rear panel speaker emits an audible tone for
each detected heartbeat. The maternal heart rate trend, when enabled, is
continuously plotted in the top (or left) grid of the strip chart paper. The MHR trace
is a grey line annotated by
MECG
. The beat-to-beat MHR signal is used for
trending on the strip chart paper and for output to external devices such as a central
station system. The
averaged MHR values are used for display and for alarm
detection.
Pacemaker Safety Information
The following safety information applies to patients with pacemakers.
WARNINGS
ACCESSORIES—Use only electrodes, lead wires, and cables
recommended by GE Medical Systems Information Technologies.
Failure to use recommended accessories may result in inaccurate
readings, damage to equipment, or loss of defibrillator protection.
FALSE ALARMS—False low heart rate alarms or false asystole
may result with certain pacemakers because of electrical
overshoot.
FALSE COUNTING—Be aware that a pacer spike could be
falsely counted as a QRS complex during asystole.
INTERFERENCE—Interference caused by electrosurgical or
diathermy instruments will affect the proper operation of the
MECG section of 250cx Series Monitors.
PACEMAKER SPIKE—Do not diagnostically interpret the
pacemaker spike size and shape; the spike may be attenuated by
the module in order to be displayed or printed.
PATIENT OBSERVATION—Keep pacemaker patients under
close observation.