12 Monitoring Triple FHRs
123
Separating FHR Traces
To help you to interpret traces with similar baselines, you can separate the baselines by an offset of
20 bpm by switching trace separation on. For details of the offset, see “Determining the Separation
Order” on page 116.
"Standard" Separation Order
To make differentiating the traces easier, the trace for FHR2 is offset by +20 bpm, and the trace for
FHR3 is offset by -20 bpm. In other words, the trace for FHR2 is recorded 20 bpm higher than it
really is, while the trace for FHR3 is recorded 20 bpm lower than it really is. The trace for FHR1 is
never shifted.
• The recorder prints a dotted line labeled across the FHR scale, to identify the trace for FHR2.
• The recorder prints a dotted line labeled across the FHR scale, to identify the trace for FHR3.
• The FHR trace is labeled and every 5cm.
• The label for FHR2 is annotated with and the FHR3 label is annotated with .
The following trace shows triplets with
Trace Separation on, and using Standard separation order.
The traces for FHR2 and FHR3 are offset. The numerical FHR values displayed on the monitor
remain unchanged. Subtract 20 from the recorded trace for FHR2 to obtain the true FHR2. For
example, if the recorded trace shows 160, then the true FHR is 140. Similarly, add 20 to the recorded
trace for FHR3 to obtain the true FHR3.
"Classic" Separation Order
To make differentiating the traces easier, the trace for FHR1 is offset by +20 bpm, and the trace for
FHR3 is offset by -20 bpm. In other words, the trace for FHR1 is recorded 20 bpm higher than it
really is, while the trace for FHR3 is recorded 20 bpm lower than it really is. The trace for FHR2 is
never shifted.
• The recorder prints a dotted line labeled across the FHR scale, to identify the trace for FHR1.
• The recorder prints a dotted line labeled across the FHR scale, to identify the trace for FHR3.
• The FHR trace is labeled and every 5cm.
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