5.3
Heart Rate Processing
The Doppler audio signal is amplified and filtered. It's amplitude is then regulated after
passing through a low-pass anti-aliasing filter. The signal is then sampled by the
microcontroller in order to calculate the fetal heart rate.
5.4
Fetal Movement Detection (FMD)
The BD4000 and BD4002 will annotate the fetal heart trace towards the top of the
contraction channel when a fetal movement is detected.
This movement is derived from low frequency Doppler signals from the Ultrasound
Transducer.
The FMD can be enabled via the front panel and its sensitivity set.
Refer to the user manual for further information.
5.5
FECG
As an alternative to using ultrasound to monitor FHR, a FECG scalp electrode may be
used.
This makes a direct connection to the fetal scalp and provides more reliable tracking of
the fetal heart rate during the later stages of labour.
The FECG transducer incorporates an isolation amplifier which provides electrical
isolation between the patient and the monitor.
5.6
IUP
In some markets Intra Uterine Pressure measurements are made as an alternative to the
external Toco transducer supplied as standard.
Patient electrical isolation is provided by an adaptor box plugged into the Toco socket
and a corresponding waveform is printed on the contractions trace either shown in
millimetres of Mercury (mmHg) or kiloPascals (kPa).
The pressure sensor is either inserted directly into the mother using the Intran Plus IUP
400 Disposable IUP System (Utah Medical Products inc). Alternatively using the
SensoNor SP844 pressure sensor and a saline filled catheter system. Refer to user
manual for further information.
Issue: 2 DRAFT
15
Rev: a
614365
