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(b)(4).A patient was being monitored, with some short breaks for a period of about 7 hours, switching between the standard wired transducers and the wireless ones at different times.The fetus was stillborn at the end of the last ctg recording.We are advised that the preliminary post-mortem report suggests that the fetus had actually died approximately 12 hours before the stillbirth (approx 5 hours before the start of monitoring on the (b)(4)).The question being asked is what signal might the fetal monitor have been detecting to produce the fhr trace.It was added that this did not look like maternal heart rate tracking.Device details: part 1 reported adverse event.Date first sold ((b)(4)): (b)(4) 2008.(b)(4).Date of manufacture: the unit in question was manufactured: no serial number available, but believed to be approx 2 years old.Date the problem or adverse incident occurred or was detected: the incident was reported to us by (b)(6), (via email) on the (b)(6) 2014.Investigation of the cause of the incident two trace images were given for analysis.These have been reviewed and the following observations made: trace 1 started at 13:27 on the (b)(6) 2014 - duration approx 30 minutes.Trace 2 started at 14:34 on the (b)(6) 2014 - duration approx 7 hours (with short breaks).The primary observation from examination of these traces is that the fhr traces would appear to be tracking patterns that reflect genuine fetal responses - this includes what would appear to be both variable and early decelerative patterns which are typical fetal patterns.There is no evidence to suggest that this is tracking maternal rate for any length of time - there is a short period from 18:39 to 18:54 which includes intermittent artifact that may be maternal rate.Elsewhere in the trace occasional short bursts of artifact may be maternal in origin, but there is no evidence of any prolonged maternal tracking of a nature that might lead to misinterpretation of the trace.There is no known alternative physiological signal source that could give rise to this trace pattern there is no known mechanism whereby this pattern could have been artificially generated within the monitor itself during the second trace, the user(s) switched between wired and wireless transducer monitoring.Hand written annotations are interpreted as recording that the patient adopted a range of positions at different times including being outside the delivery room at times (in wireless mode).These transducers are different in design and clearly will have been positioned independently of each other following natural breaks.However, both monitoring methods reflect a very similar fhr type pattern.It is inconceivable that, throughout this period, with different transducers being used at different times, with the patient in a range of positions/locations, that maternal heart rate was being tracked continuously instead of fetal, or that some other signal source was being continuously tracked.Irrespective of what appears on the trace, the audio output would have been available to listen to.This is not subject to the same well-documented double rate, false tracking risks associated with the printed rate information.Where mhr was recorded (using spo2), there is no evidence of maternal tachycardia that might lead to the user thinking this was a fetal sound, and, as already stated, rate doubling cannot occur on the audio.It would therefore be obvious from this audio output as to whether this was fetal or maternal in origin.It is noted that the antenatal care analysis was used on the whole of the 1st trace and for part of the 2nd trace, with the stv being hand written on the second trace.On this 2nd trace, the full analysis results would normally have been printed at the end of the trace, but this has not been included in the photocopy of the trace supplied to us.From the contractions trace, it would appear that the patient was in established labour, with contractions activity being recorded throughout the full monitoring period.This analysis is not approved for use during labour.This is clearly stated in the "intended use" statement in the fm830e ifu.It is noted, however, that the first analysis did highlight that the criteria for normality were not met, for multiple reasons, which might reasonably be expected to have raised concern about the fetus, although use of this during labour does represent "off label" use.The second analysis outcome is not available - stv is hand-annotated on the trace as being 6.1 (at 16:38).Stv should only be assessed within the context of a full 60-minute analysis and only within the context of the full analysis results - while an abnormal stv (<3ms) is strongly associated with high risk of intrauterine death, a normal stv is not, on its own, an indicator of the absence of risk.Conclusion: it is concluded that there is no evidence that the fetal heart rate traces in the two supplied photocopy images represent anything other than genuine fetal heart rate information, and that there is no evidence of any machine or other induced artificial signal source being involved.This is clearly at odds with the stated findings of the preliminary post mortem report, which suggest that the fetus died in utero approximately 5 hours before the start of the first trace.We are unable to either explain, or comment further, on this discrepancy.This report, and the traces, have been independently reviewed by a local consultant obstetrician, who confirmed that she was in full agreement with our findings and our conclusion that the fetus was alive upto somewhere around 21:oo on the (b)(6) may (trace time- this assumes the ctg clock was correctly set).Risk assessment: risk management file has been reviewed and concluded that the mitigation of the associated risks are appropriate,have been adequately documented and are acceptable, i.E., warnings have been included in relevant areas.However, we cannot state the problem will not reoccur as further mitigation of these risks is outside our direct control, being driven by local and national guidelines, protocols, training and individual clinician's practices.
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