11 Monitoring FHR and FMP Using Ultrasound
Signal Quality Indicator
Avalon compared with its predecessor, the Series 50
Signal quality indicator on Avalon fetal monitors:
Instead of a traffic light-like design (red – yellow – green) used on the Series 50, the signal quality on
the Avalon fetal monitor is indicated by a triangle on the touch screen that is displayed in one of three
Examples of Artifacts
When monitoring the maternal ECG, a beat-to-beat maternal heart rate trace is printed alongside the
FHR recorded trace. When monitoring the maternal SpO
heart rate trace is printed.
Following are recorded trace examples of complaints received regarding inaccurate output from the
Avalon monitors. Scaling is 3 cm/min and 30 bpm/cm.
Avalon fetal monitor signal quality indicator display:
Completely filled triangle, indicating good signal quality
Half-filled triangle, indicating limited signal quality. This
condition may indicate a weak or ambiguous signal. If
this status persists, reposition the transducer
Empty triangle, indicating insufficient signal quality. No
FHR is displayed on the monitor's numeric display or
the recorded trace. If this status persists, reposition the
transducer (poor/no signal).
derived pulse rate, a filtered and averaged