Clinical Trial Details
— Status: Recruiting
Administrative data
| NCT number |
NCT04574739 |
| Other study ID # |
2019-01899 |
| Secondary ID |
|
| Status |
Recruiting |
| Phase |
|
| First received |
|
| Last updated |
|
| Start date |
July 1, 2020 |
| Est. completion date |
October 31, 2020 |
Study information
| Verified date |
September 2020 |
| Source |
University Hospital Inselspital, Berne |
| Contact |
Anda Radan |
| Phone |
0316321010 |
| Email |
anda-petronela.radan[@]insel.ch |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Observational [Patient Registry]
|
Clinical Trial Summary
Fetal monitoring by transabdominal electrocardiogram recording
Description:
Cardiotocography (CTG), or electronic fetal monitoring (EFM), is the most common procedure
used for fetal assessment before and during labour and largely replaced the use of
intermittent heart rate auscultation with the Pinard stethoscope or intrapartal analysis of
fetal pH by scalp sampling. It relies on acoustic methods in the audible (auscultation) and
inaudible range of the sound spectrum (ultrasound). Ever since its introduction in the late
1960s, the benefit of the method has been controversial. Not only the great inter- and
intra-observer variability due to visual interpretation of CTG traces seems to be an issue,
but also the technical difficulties of the method: data assessment in adipose patients,
active fetuses or multiple gestation, confusions between fetal and maternal pulse, assessment
during water delivery, strong contractions or changing labour positions of the parturient. It
is common knowledge that CTG leads to unnecessary medical interventions such as caesarean
section and vaginal-operative deliveries, with the associated health consequences and
economic costs.
Despite the continuous progress made in CTG technology in the past 50 years, CTG devices
still have drawbacks, namely their bulkiness (including cables and bedside computers),
combined with the limited informative value and suboptimal reliability of the measured
signals. The assessment can be uncomfortable for the pregnant patient, due to the fact that
the patient is bound to a machine and implicitly to the bed, particularly when a longer
surveillance is needed. Long periods of immobility can lead to further medical and psychical
problems during pregnancy.
Wireless methods of fetal monitoring exist; nevertheless, the technical difficulties of the
assessment seem to be more pronounced when these are employed.
Routine continuous monitoring of physiological signals in normal and extraordinary
environments provides useful insides for better understanding and modelling of human
physiology. Under contract by the European Space Agency (ESA), the Swiss Centre for
Electronics and Microtechnology (CSEM) has designed and developed the LTMS system (Long Term
Medical System) system. In 2003, ESA commissioned CSEM to do a definition study for a
prototype of LTMS. Following the outcomes of this study, in 2006 CSEM built a first prototype
(LTMS-2) for ESA, which was validated at Bern University Hospital in 2008. In the subsequent
phase (LTMS-3, 2009-2010), CSEM manufactured a set of upgraded systems which were validated
in Antarctica (Concordia Station) in 2010 and during the Rio-Tinto field test of the Austrian
Space Forum spacesuit simulator in 2011. In 2015, CSEM delivered to ESA a new sensor system
(LTMS-S) with yet improved measuring functionalities and higher overall integration in an
easy to-wear vest. The system has been shipped to the Concordia Station in Antarctica for the
scientific investigation for monitoring the physiological adaptation of manned crews in
remote, isolated, and extreme environments. An in-depth clinical validation study at the
University Hospital in Lausanne has shown that the performance of the system was within the
contractual specifications and that it fulfilled the requirements set by international
medical standards.
Although it has initially been proposed to adapt and use LTMS-S for fetal ECG (fECG)
measurements, reconsidering the required noise level and resolution to capture fECG, it has
been decided to modify and use the ECGi-CDWe system, which has evolved from LTMS-S and
belongs to the cooperative sensors family of CSEM. This system outperforms LTMS-S in terms of
noise level, resolution, and also number of electrodes that can be connected (>200). The said
system has been designed in the frame of an industrial mandate by respecting the requirements
of medical device development. Therefore a reduced version of ECGi-CDWe has been developed,
hereafter called ELAINE system.
The objective of the proposed project ELAINE is to build a state of the art fetal
surveillance system using this technology and by applying electrocardiography (ECG) as main
surveillance method. The project leaders believe that this could substantially improve the
quality of continuous fetal monitoring before and during labour, in particular in terms of
specificity. From measuring a full ECG with the detachable ELAINE sensors instead of heart
rate-based CTG, the project leaders expect a higher reliability in the monitoring of the
health status of the unborn. The systems based on LTMS technology are unobtrusive and do not
require cabling to bedside devices, increasing the maternal comfort.
As mentioned before, the goal of the study is to adapt the ECGi-CDWe technology for fetal
surveillance. The full currently existing adult oriented LTMS-S system consists of a Master
unit connected to 8 measurement units via 2 cables. Reference and Guard electrode connections
are an integral part of the Master unit. The system is powered by a single battery attached
to the Master unit. 8 measurement units are powered from the Master unit via the 2 cables
connecting them to the Master unit. ELAINE system, being a part of the cooperative sensors
family of CSEM, benefits from a simple cabling scheme as opposed to the star topology
connection employed in almost any multi-lead ECG measurement systems in the market.
On one hand, the ELAINE sensors are small, unobtrusive and comfortable to wear. On the other
hand, they deliver a wide range of detailed signals with high accuracy. The ECG measured with
ELAINE contains for example all the information necessary to diagnose arrhythmic heart
diseases. The demonstrated high accuracy of the technology will enable the responsible team
at CSEM and the project leaders to record full fetal ECGs (fECGs), thus giving a more
accurate image of the cardiac health status of the fetus and making interventions more
effective. To make diagnoses even more accurate, the sensors developped by CSEM measure a
wealth of additional, signals, e.g. body sounds (potential for fetal heart auscultation),
muscular activity (ideal for measuring contractions), vibrations (physical activity of the
fetus). Finally, the ELAINE technology allows connecting many sensors in a very simple manner
(employing only a single two-wire bus for all sensors), making it very easy to simultaneously
record signals on different spots of the mother's body.
The ECG monitoring sensors will be tested at the Maternity Ward of the University Hospital of
Bern, in a first phase before labour.
A two-step validation has been planned to validate the measurements performed by the ELAINE
system: first it will be validated against the non-invasive gold standard to measure fetal
heart rate, i.e. CTG, and secondly it will be validated against a conventional ECG system to
measure maternal ECG. This two-step validation is justified as follows: CTG can extract fetal
heart rate information; however, not the complete ECG morphology. With ELAINE, the project
leaders claim to acquire fetal ECG signal rather than only fetal heart rate information.
Therefore, a validation only involving CTG will be a partial one. In order to complete the
validation, considering that the primary function of the ELAINE system is to acquire ECG
signals, it will be validated against a conventional ECG system which acquires maternal ECG.
In order to mitigate the risk of perturbation due to simultaneous connection of two ECG
systems, measurements will be conducted one after another - with the justification that ECG
morphology of a certain individual does not change in the time frame the experiments were
conducted. After the registration, the computer will filter and separate the two ECG curves
(fetal and maternal), based on the maternal ECG, which is available from the conventional
measurement, and on the fetal heart frequency, which is available after registration with
CTG.
Validation procedure:
During the first and last quarter of the recording duration, both ELAINE and a conventional
CTG system will be connected to the maternal abdomen. Fetal heart rate information acquired
by CTG will be compared with the one to be extracted from ELAINE. During the second and third
quarters of the recordings, only the ELAINE device will be placed on the maternal abdomen to
perform measurements in the absence of the CTG system.
Two measurement electrodes of ELAINE will be connected to the maternal chest. An ECG
recording will be performed for 5 minutes. Then a conventional 2-lead ECG will be connected
to the maternal chest upon removal of the ELAINE system. An ECG recording of same duration
will be performed.
The project leaders believe that the technology developed for ESA in the LTMS series has the
potential to fundamentally change EFM, with the end goal to improve the clinical outcomes of
deliveries. For this, the project leaders envisage a product which produces more accurate
data on the fetal health status than current CTG devices and which is more comfortable to
wear. Following the reasoning above, the project leaders think that this can be achieved with
ECG measurements. In ELAINE, the project leaders will for the first time demonstrate that the
ELAINE technology is appropriate for monitoring fetal health.
