Product Manual

4077-INS-LAB-RevB09 26
7 FETAL MONITOR OPERATION
ULTRASOUND MONITORING OF FHR
Ultrasound monitoring is a method to obtain FHR through the maternal abdominal wall.
Place the FHR transducer on the maternal abdomen to transmit the low-energy ultra-
sound wave to fetal heart, then receive the echo signal.
Ultrasound monitoring can be used for antepartum monitoring. Components required
are ultrasound transducer, aquasonic coupling gel, and belt.
Read the following warnings, then perform the following procedure, to monitor FHR.
WARNING: Do not mistake the higher maternal heart rate for fetal heart rate.
WARNING: For best quality records, place the transducer in the optimum position.
WARNING: For best quality records, avoid positions with strong placental sounds
(swishing) or fetal cord pulse (indistinct pulse at fetal rate).
WARNING: If the fetus is in the cephalic position and the mother is supine, the clear-
est heart sound will normally be found on the midline below the umbilicus. During
monitoring, prolonged lying in the supine position should be avoided. Sitting up or
lateral positions are preferable and may be more comfortable for the mother.
WARNING: It is not possible to monitor FHR unless an audible fetal heart signal is
present. The fetal pulse can be distinguished from the maternal pulse by feeling
the mother’s pulse during the examination.
Preparing the Fetal Monitor
1. Read the preceding warnings before beginning. Turn the monitor on and verify that
the normal monitoring screen displays.
2. Check the ultrasound transducer to verify proper attachment to the monitor. For
monitoring of twins, ensure the second ultrasound transducer is properly connected.
3. Set the current heart rate channel to US1, and adjust US1 speaker volume as needed.
4. Attach the ultrasound transducer buckle to the belt.
5. Apply aquasonic coupling gel to the face of the transducer.
Acquiring the Fetal Heart Signal
1. Determine the location of the fetal heart using palpation or a fetoscope.
2. Place the ultrasound transducer on the abdomen over fetal site and move it slowly
until the characteristic hoof-beat sound of the fetal heart is heard (see the picture at
right for the approximate positioning of the FHR transducer).
3. The elasticity of the belt can be adjusted for maternal com-
fort. The fetal heart rate value and trend will display on the
screen.
4. Readjust the volume settings as needed.
transducer
position
measure
TOCO
measure
FHR