Aim
To alert clinicians to the possibility of interference with fetal monitoring when a TENS machine is being used while a FSE is in-situ.
Background
Fetal monitoring using a FSE is increasingly common and is an important tool to ensure accurate monitoring in labour where continuous CTG monitoring is indicated. Accurate CTG monitoring can improve informed decision making, and a correctly applied FSE can allow the women increased freedom of movement in labour and reduce the need for continued repositioning of ultrasound probes.
TENS machines use low voltage currents for pain relief in labour. While it has shown to be safe, it has not been tested or reviewed for use with FSE. Additionally, FSE has not been tested or reviewed for use with TENS. For this reason, it is not recommended that TENS be used concurrently with FSE.
It is essential when an FSE is used a correctly sized electrode is used to attach the leg plate to maternal skin, as this provides the maternal reference needed for the monitor to distinguish the fetal ECG from the maternal ECG. Check with manufactures as to the correct sized leg plate
Recommendation
A TENS machine should not be used concurrently with an FSE as it may introduce artefact into the CTG trace.
Implications in clinical practice
- During discussions in the antenatal period around analgesia and fetal monitoring women should be informed that TENS machines may cause interference with FSE monitoring and will likely need to use another method of pain management if FSE is required.
- Clinicians managing care of women in labour with an FSE should be aware if a TENS machine is being used, and that this should be ceased when FSE monitoring commences.
References
*This good practice point has been referenced from the Rocket and Gold trace FSE representatives as currently there are no studies in this area. Both Rocket and Gold Trace recommended not to use TENS Machines with their FSEs as they cannot guarantee CTG performance under these conditions.