Non Stationary and Multifractal Statistical Analyses of Per Partum Fetal Heart Rate for Asphyxia Diagnosis – FETUSES

Per partum fetal asphyxia (or acidosis) constitutes the third cause
for neonatal morbidity and is responsble for a third of neonatal
encephalopathies in term neonates. It is consecutive to a major
perturbation of the fetal oxygenation process.
To avoid fetal cerebral lesions induced by severe oxygen deprivation,
operative deliveries are performed, which consist of either caesarean
or instrumental extraction. Such operative deliveries are
significantly increasing risks of lesions, parietal complications and long term complications as uterine rupture with fetal death for the next pregnancy or severe haemorrhage due to placenta praevia and accreta for the mother and of cephalic and ocular trauma or hematoma and respiratory distress for the new born child.
Therefore, monitoring per partum fetal surveillance aiming at
relevant detection of fetal asphyxia, while limiting the number of unnecessary
(incorrectly decided) operative deliveries, constitutes an important stake, both for public health and economical reasons, which justifies the significant research
efforts devoted to it.
Currently, clinical per partum fetal surveillance relies mostly on
visual inspection of real-time on-line recordings of fetal
heart rate. Decisions for operative deliveries are based on a set of rules due to
the International Federation of Gynecology and Obstetrics, yet still
depend heavily on the obstetrician experience. This
analysis enables a reliable detection of acidosis where
missed detections (False Negatives) must be avoided, at the price
though of a high rate of false positive detections, leading to
unneeded operative deliveries. Optimizing the False Negative versus
False Positive trade-off is one of the key challenges of the FETUSES
project.
Fetal heart rate analysis provides a valuable index describing
subject's health status and autonomous nervous system dynamics, and
hence is a major research topic of world-wide interest. As an example,
the American project PHYSIONET devotes a significant amount of
international research effort to adult heart beat variability; the
European STAN project elaborates on fetal monitoring international
standardisation (the medical team involved in FETUSES is the only
French team participating in it); and, two French teams study cardiac
variability for prematures or animals. FETUSES concentrates more
specifically on the analysis of per partum fetal heart rate.
The FETUSES project relies deeply and crucially on the construction of
a truly interdisciplinary research program, gathering skills and
knowledges of both medical and statistical signal processing teams,
which are recognized as world-leading experts in their fields. FETUSES
will combine in a single research program a significant amount of
knowledge on fetal heart rate and acidosis detection with a solid
expertise in modern statistical signal processing tools. These
interactions will be eased by the geographical vicinity, within the
city of Lyon, of the research teams involved. These teams have already
undertaken the drawing of a common research framework, whose
formalization results in the present ANR proposal.
The goals of the FETUSES project consist of the developments of
statistical signal processing tools dedicated to per partum fetal
heart rate characterization and acidosis detection, and are organized
as follows :
- Construction of a large database of per partum fetal heart rate
recordings, which is well documented and of significant clinical
value;
- Developments of adaptive (i.e., data driven) algorithms to separate
data into trend (decelerations induced by contractions) and
fluctuation (cardiac variability) components ;
- Developments of algorithms to characterize the non stationary and
multifractal properties of per partum fetal heart rate ;
- Acidosis detection and assessment using the large database ;
- Algorithm implementations for performing tests in real clinical situations.