Philips Avalon FM20, Instructions For Use Manual

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10 Monitoring FHR and FMP Using Ultrasound
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Audio Output
The audio output from the device is an aural representation of movement that, in most cases, permits
accurate auscultation of the FHR corresponding to the FHR displayed on the monitor and rate pattern
depicted on the trace recording. On occasion, the user may hear a FHR in the audio output that differs
from the FHR display and the recorded trace. This may occur in situations where the fetal heart moves
partly out of the transducer ultrasound beam. In these cases, the user may still audibly recognize the
FHR in the audio output of the monitor’s speaker, even though another periodic signal (usually the
maternal heart rate) has become stronger. The autocorrelation algorithm will display the stronger
maternal heart rate, despite the persistence of a weaker fetal signal. These occurrences are usually very
brief and, if persistent, can be addressed by repositioning the transducer.
User Interface
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
ways:
Avalon Fetal Monitor signal quality indicator display
1 Completely filled triangle, indicating good signal quality (good/full).
2 Half-filled triangle, indicating limited signal quality. This condition may indicate a weak or
ambiguous signal. If this status persists, reposition the transducer (acceptable/medium).
3 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).
Cross-Channel Verification (CCV) indication on Avalon fetal monitors
If the Cross-Channel Verification detects a probable duplication of information from both the MHR
channel input device (maternal ECG or pulse oximeter) and the fetal transducer, the corresponding
recorded trace segment is annotated with question marks at the upper edge of the heart rate grid. This
is the same for the Avalon fetal monitor and the Series 50. In addition, the Avalon fetal monitor
provides an annotation on the recorded trace to indicate which heart rates coincide. The Avalon fetal
monitor also identifies coincidence with a question mark on the FHR numeric display, indicating that
the FHR being displayed may actually be the maternal heart rate (see image below). When multiple