Monitoring Twin FHRs
The FHRs of twins are externally monitored using two ultrasound transducers. The Avalon CL
Transducer system provides the option to monitor twins with cableless transducers. The Avalon CTS
system does not have this option.
Twin FHRs are monitored throughout labor and delivery. After rupture of the membranes, you can
monitor one twin externally using ultrasound, and the other internally using DECG.
Refer to the appropriate preceding chapters for contraindications, and more information about the
available measurement methods.
FHR detection by the monitor does not always indicate that the fetuses are alive. Confirm fetal life
before monitoring, and continue to confirm that the fetuses are the signal source for the recorded fetal
heart rates. See "Confirm Fetal Life Before Using the Monitor" on page 10 and "Cross-Channel
Verification (CCV)" on page 135.
Ensure that you are recording two different fetal heart rates. The cross-channel verification feature
alerts you if the two heart rates coincide (if both transducers are recording the same FHR). If this
happens, check the trace and if necessary, reposition an ultrasound transducer to detect the second
Fetal heart rate measurements are labeled in the order in which you plug in the transducers for
those measurements. It does not matter which fetal sensor socket you use, as the monitor allocates
a channel automatically. For instance, the first transducer you connect is automatically allocated a
channel, and the measurement is labeled
If you need to disconnect the transducers measuring the FHR temporarily, with the intention to
continue monitoring after the temporary break (for example, if the mother needs to go to the
bathroom), it is important that you reconnect the transducers in the same order as you originally
connected them to make sure the measurement labels remain consistent.
Upon discharge of the patient all connected transducers are reset from left to right. Example: Only one
transducer is still connected to the monitor, it was labeled
discharged patient; it is now reset to
The transducer Finder LED lets you identify at a glance which transducer is monitoring which
heart rate channel.
, the second is labeled
, and so on.
while monitoring the previous