Maternal Respiration Research Articles

143 Short- and long-term effects of heat stress in cow-calf pairs adapted to tropical and subtropical regions

Abstract Chronic exposure to high temperatures and humidity can limit beef cattle performance in tropical/subtropical environments, regardless of breed. Despite better heat adaptability compared with Bos taurus cattle, heat-stressed Bos indicus cattle also experience an increase in body temperature above the physiological limit. As body temperature increases, cascades of behavioral and physiological events are triggered to lessen heat load but often at the expense of productive outcomes. Contrary to other species and feedlot beef cattle, the effects of heat stress on physiology and performance of grazing cow-calf pairs have not been evaluated in detail, particularly for Bos indicus cattle. Preliminary data showed opposite outcomes to heat stress in Bos indicus vs. Bos taurus cattle, limiting the implications of the existing data generated from studies using beef and dairy Bos taurus cattle. This presentation will share some nutritional and management practices to mitigate heat stress in grazing beef cattle. Practices mentioned herein include altering the timing of body weight (BW) growth pattern (stair-step, SST) and immunomodulatory feed ingredient (IFI) supplementation for replacement beef heifers, and maternal access to shade to reduce heat load. For 100 d before the breeding season, Bos indicus-influenced beef heifers grazing warm-season grasses received a constant supplementation amount or SST strategy (50 d of low then 50 d of high supplementation), with or without IFI. Under severe heat stress conditions, IFI supplementation reduced heifer vaginal temperature but did not increase their growth and reproduction, whereas the SST strategy lowered internal body temperature, enhanced growth performance and pregnancy success compared with a conventional constant supplementation practice. Our group is also focused on the critical need to determine the specific effects of heat stress mitigation during pre- and postnatal phases on physiology and performance of Bos indicus-influenced cow-calf pairs. Study 1 evaluated the impacts of maternal access to artificial shade from 83 d prepartum until 50 d postpartum on body thermoregulation, performance, and physiology of beef heifers and their first offspring. Removing maternal access to shade led to greater maternal respiration rate, vaginal and body surface temperatures and reduced maternal body condition score and calf BW at birth. Nonetheless, offspring born from cows with no access to shade were remarkably heavier during a 60-d post-weaning period and had decreased plasma indicators of inflammation and positive effects to humoral immune response. Study 2 is a multi-year, USDA/NIFA-funded study designed to capitalize on the ability of cattle to reprogram physiological/immunological systems following exposure to stress during gestation. Study 2 combined gestational and postnatal heat abatement to enhance the overall growth/immune/reproductive performance of grazing Bos indicus-influenced cow-calf pairs. Partial data on long-term growth and reproductive performance, physiology, metabolome, and microbiome of both cows and their female offspring will be shared in this presentation.

Adaptive Filtering for the Maternal Respiration Signal Attenuation in the Uterine Electromyogram.

The electrohysterogram (EHG) is the uterine muscle electromyogram recorded at the abdominal surface of pregnant or non-pregnant woman. The maternal respiration electromyographic signal (MR-EMG) is one of the most relevant interferences present in an EHG. Alvarez (Alv) waves are components of the EHG that have been indicated as having the potential for preterm and term birth prediction. The MR-EMG component in the EHG represents an issue, regarding Alv wave application for pregnancy monitoring, for instance, in preterm birth prediction, a subject of great research interest. Therefore, the Alv waves denoising method should be designed to include the interference MR-EMG attenuation, without compromising the original waves. Adaptive filter properties make them suitable for this task. However, selecting the optimal adaptive filter and its parameters is an important task for the success of the filtering operation. In this work, an algorithm is presented for the automatic adaptive filter and parameter selection using synthetic data. The filter selection pool comprised sixteen candidates, from which, the Wiener, recursive least squares (RLS), householder recursive least squares (HRLS), and QR-decomposition recursive least squares (QRD-RLS) were the best performers. The optimized parameters were L = 2 (filter length) for all of them and λ = 1 (forgetting factor) for the last three. The developed optimization algorithm may be of interest to other applications. The optimized filters were applied to real data. The result was the attenuation of the MR-EMG in Alv waves power. For the Wiener filter, power reductions for quartile 1, median, and quartile 3 were found to be −16.74%, −20.32%, and −15.78%, respectively (p-value = 1.31 × 10−12).

A non-invasive multimodal foetal ECG\u2013Doppler dataset for antenatal cardiology research

Non-invasive foetal electrocardiography (fECG) continues to be an open topic for research. The development of standard algorithms for the extraction of the fECG from the maternal electrophysiological interference is limited by the lack of publicly available reference datasets that could be used to benchmark different algorithms while providing a ground truth for foetal heart activity when an invasive scalp lead is unavailable. In this work, we present the Non-Invasive Multimodal Foetal ECG-Doppler Dataset for Antenatal Cardiology Research (NInFEA), the first open-access multimodal early-pregnancy dataset in the field that features simultaneous non-invasive electrophysiological recordings and foetal pulsed-wave Doppler (PWD). The dataset is mainly conceived for researchers working on fECG signal processing algorithms. The dataset includes 60 entries from 39 pregnant women, between the 21st and 27th week of gestation. Each dataset entry comprises 27 electrophysiological channels (2048 Hz, 22 bits), a maternal respiration signal, synchronised foetal trans-abdominal PWD and clinical annotations provided by expert clinicians during signal acquisition. MATLAB snippets for data processing are also provided.

Human Fetal Blood Flow Quantification with Magnetic Resonance Imaging and Motion Compensation.

Magnetic resonance imaging (MRI) is an important tool for the clinical assessment of cardiovascular morphology and heart function. It is also the recognized standard-of-care for blood flow quantification based on phase contrast MRI. While such measurement of blood flow has been possible in adults for decades, methods to extend this capability to fetal blood flow have only recently been developed. Fetal blood flow quantification in major vessels is important for monitoring fetal pathologies such as congenital heart disease (CHD) and fetal growth restriction (FGR). CHD causes alterations in the cardiac structure and vasculature that change the course of blood in the fetus. In FGR, the path of blood flow is altered through the dilation of shunts such that the oxygenated blood supply to the brain is increased. Blood flow quantification enables assessment of the severity of the fetal pathology, which in turn allows for suitablein uteropatient management and planning for postnatal care. The primary challenges of applying phase contrast MRI to the human fetus include small blood vessel size, high fetal heart rate, potential MRI data corruption due to maternal respiration, unpredictable fetal movements, and lack of conventional cardiac gating methods to synchronize data acquisition. Here, we describe recent technical developments from our lab that have enabled the quantification of fetal blood flow using phase contrast MRI, including advances in accelerated imaging, motion compensation, and cardiac gating.

Ontogenetic changes in energy expenditure and resting behaviour of humpback whale mother–calf pairs examined using unmanned aerial vehicles

Context Baleen whale calves rapidly increase in size and improve locomotion abilities, while on their low-latitude breeding ground, allowing them to undertake a successful migration to high-latitude feeding grounds. Aims We investigated energy expenditure and resting behaviour of humpback whale (Megaptera novaeangliae) mother–calf pairs in regard to changes in calf length on an undisturbed breeding/resting ground off Exmouth Gulf, Western Australia. Methods Data were collected from August to October in 2018 and 2019 on lactating mothers that were predominantly resting on the surface with their calf. Focal follows on mother–calf pairs (n = 101) were conducted using an unmanned aerial vehicle to obtain detailed video of behaviours and respirations (23.7 h). Body length measurements of individual whales were calculated from aerial still frames. Key results Results on calves ranging in length from ~4–8 m demonstrated that calf respiration rate decreased with an increase in calf length and increased with presence of activity (P < 0.001). Calf inter-breath intervals became longer in duration with an increase in calf length (P < 0.01). Calf activity level and resting behaviour remained constant, with calves logging for 53% of the time their mothers were logging. Maternal respiration rate remained low and did not differ with respect to maternal or calf length. Conclusions Results highlighted the importance of resting grounds for energy preservation, which benefits the calves’ rapid growth before migration to polar waters. Implications Findings from the present largely undisturbed population serve as a baseline for understanding the impacts of anthropogenic disturbance on resting behaviour and energy expenditure in humpback whale mother–calf pairs globally.

A Novel Tool for Non-Invasive Fetal Electrocardiography Research: the NInFEA Dataset.

In this work, a novel open-source dataset for noninvasive fetal electrocardiography research is presented. It is composed of 60 high-quality electrophysiological recordings acquired between the 21st and the 27th weeks of gestation. For each acquisition, whose average duration is 30.5 s, 24 unipolar abdominal leads and three bipolar thoracic leads were included, along with a maternal respiration signal collected by a thoracic resistive belt. The chosen electrodes positioning map allows reproducing up to ten setups presented in the scientific literature. Each biopotential recording was acquired synchronously with the corresponding fetal cardiac pulsed-wave Doppler (PWD) signal, to provide complete information about the fetal cardiac cycle, both from the electrical and mechanical point of view.This is the first dataset allowing the non-invasive fetal ECG analysis even in early pregnancies with a ground truth about the fetal heart activity, given by the PWD signal. For this reason, it can be used to assess fetal ECG extraction algorithms requiring multiple channels, eventually including maternal references. This dataset is being released on Physionet by the end of June 2020 and will be continuously improved in the framework of the Non-Invasive Fetal ECG Analysis (NInFEA) project of the University of Cagliari (Italy).

Assessment of Radiomics and Deep Learning for the Segmentation of Fetal and Maternal Anatomy in Magnetic Resonance Imaging and Ultrasound

Recent advances in fetal imaging open the door to enhanced detection of fetal disorders and computer-assisted surgical planning. However, precise segmentation of womb's tissues is challenging due to motion artifacts caused by fetal movements and maternal respiration during acquisition. This work aims to efficiently segment different intrauterine tissues in fetal magnetic resonance imaging (MRI) and 3D ultrasound (US). First, a large set of ninety-four radiomic features are extracted to characterize the mother uterus, placenta, umbilical cord, fetal lungs, and brain. The optimal features for each anatomy are identified using both K-best and Sequential Forward Feature Selection techniques. These features are then fed to a Support Vector Machine with instance balancing to accurately segment the intrauterine anatomies. To the best of our knowledge, this is the first time that "Radiomics" is expanded from classification tasks to segmentation purposes to deal with challenging fetal images. In addition, we evaluate several state-of-the-art deep learning-based segmentation approaches. Validation is extensively performed on a set of 60 axial MRI and 3D US images from pathological and clinical cases. Our results suggest that combining the selected 10 radiomic features per anatomy along with DeepLabV3+ or BiSeNet architectures for MRI, and PSPNet or Tiramisu for 3D US, can lead to the highest fetal / maternal tissue segmentation performance, robustness, informativeness, and heterogeneity. Therefore, this work opens new avenues for advancement of segmentation techniques and, in particular, for improved fetal surgical planning.

Accuracy of electromyometrial imaging of uterine contractions in clinical environment

Clinically, uterine contractions are monitored with tocodynamometers or intrauterine pressure catheters. In the research setting, electromyography (EMG), which detects electrical activity of the uterus from a few electrodes on the abdomen, is feasible, can provide more accurate data than these other methods, and may be useful for predicting preterm birth. However, EMG lacks sufficient spatial resolution and coverage to reveal where uterine contractions originate, how they propagate, and whether preterm contractions differ between women who do and do not progress to preterm delivery. To address those limitations, electromyometrial imaging (EMMI) was recently developed and validated to non-invasively assess three-dimensional (3D) electrical activation patterns on the entire uterine surface in pregnant sheep. EMMI uses magnetic resonance imaging to obtain subject-specific body-uterus geometry and collects uterine EMG data from up to 256 electrodes on the body surface. EMMI software then solves an ill-posed inverse computation to combine the two datasets and generate maps of electrical activity on the entire 3D uterine surface. Here, we assessed the feasibility to clinically translate EMMI by evaluating EMMI's accuracy under the unavoidable geometrical alterations and electrical noise contamination in a clinical environment. We developed a hybrid experimental-simulation platform to model the effects of fetal kicks, contractions, fetal/maternal movements, and noise contamination caused by maternal respiration and environmental electrical activity. Our data indicate that EMMI can accurately image uterine electrical activity in the presence of geometrical deformations and electrical noise, suggesting that EMMI can be reliably translated to non-invasively image 3D uterine electrical activation in pregnant women.

Fetal Cardiac MRI: A Review of Technical Advancements.

Magnetic resonance imaging (MRI) is an appealing technology for fetal cardiovascular assessment. It can be used to visualize fetal cardiac and vascular anatomy, to quantify fetal blood flow, and to quantify fetal blood oxygen saturation and hematocrit. However, there are practical limitations to the use of conventional MRI for fetal cardiovascular assessment, including the small size and high heart rate of the human fetus, the lack of conventional cardiac gating methods to synchronize data acquisition, and the potential corruption of MRI data due to maternal respiration and unpredictable fetal movements. In this review, we discuss recent technical advances in accelerated imaging, image reconstruction, cardiac gating, and motion compensation that have enabled dynamic MRI of the fetal heart.

Partial amniotic carbon dioxide insufflation (PACI) during minimally invasive fetoscopic interventions on fetuses with spina bifida aperta.

Percutaneous partial amniotic carbon dioxide insufflation (PACI) is one of the most important means for improving visualization during minimally invasive fetoscopic surgery of fetal spina bifida. The purpose of the present study was to analyze maternal and fetal safety aspects of PACI in a recent patient cohort and to present management improvements. PACI under general materno-fetal anesthesia was performed during 65 interventions for fetoscopic patch coverage of fetal spina bifida aperta between 21 + 0 and 29 + 1weeks of gestation. Filtered carbon dioxide was insufflated into the amniotic cavity via three percutaneously introduced trocars. Maternal ventilatory and hemodynamic parameters during PACI as well as insufflation pressures, BMI, parity, and placental position were recorded and statistically analyzed in order to detect potential risk groups. Maternal respiration parameters during PACI showed a typical variation over time, which was similar in patients with BMI ≤ 25 or BMI > 25. The necessary insufflation pressures were significantly higher in nulliparae than multiparae. There was no statistically significant relationship between insufflation pressure and maternal BMI, or between the expired maternal carbon dioxide concentration (etCO2) and the placental position. PACI was safe for all mothers and fetuses. Postnatal demise in one neonate, one fetus, and two infants occurred unrelated to PACI and resulted from trisomy 13, infection, and severe Chiari II malformations, respectively. PACI seems safe in order to improve visualization of intraamniotic contents during minimally invasive fetoscopic surgery. Nevertheless, continued assessments of its benefits and risks are important.

Placenta Maps: In Utero Placental Health Assessment of the Human Fetus.

The human placenta is essential for the supply of the fetus. To monitor the fetal development, imaging data is acquired using (US). Although it is currently the gold-standard in fetal imaging, it might not capture certain abnormalities of the placenta. (MRI) is a safe alternative for the in utero examination while acquiring the fetus data in higher detail. Nevertheless, there is currently no established procedure for assessing the condition of the placenta and consequently the fetal health. Due to maternal respiration and inherent movements of the fetus during examination, a quantitative assessment of the placenta requires fetal motion compensation, precise placenta segmentation and a standardized visualization, which are challenging tasks. Utilizing advanced motion compensation and automatic segmentation methods to extract the highly versatile shape of the placenta, we introduce a novel visualization technique that presents the fetal and maternal side of the placenta in a standardized way. Our approach enables physicians to explore the placenta even in utero. This establishes the basis for a comparative assessment of multiple placentas to analyze possible pathologic arrangements and to support the research and understanding of this vital organ. Additionally, we propose a three-dimensional structure-aware surface slicing technique in order to explore relevant regions inside the placenta. Finally, to survey the applicability of our approach, we consulted clinical experts in prenatal diagnostics and imaging. We received mainly positive feedback, especially the applicability of our technique for research purposes was appreciated.

Motion compensated cine CMR of the fetal heart using radial undersampling and compressed sensing

BackgroundTo develop and evaluate a reconstruction framework for high resolution time-resolved CMR of the fetal heart in the presence of motion.MethodsData were acquired using a golden angle radial trajectory in seven fetal subjects and reconstructed as real-time images to detect fetal movement. Data acquired during through-plane motion were discarded whereas in-plane motion was corrected. A fetal cardiac gating signal was extracted to sort the corrected data by cardiac phase, allowing reconstruction of cine images. The quality of motion corrected images and the effect of data undersampling were quantified using separate expressions for spatial blur and image error.ResultsMotion corrected reordered cine reconstructions (127 slices) showed improved image quality relative to both uncorrected cines and corresponding real-time images across a range of root-mean-squared (RMS) displacements (0.3–3.7 mm) and fetal heart rates (119–176 bpm). The relative spatial blur between cines with and without motion correction increased with in-plane RMS displacement leading to an effective decrease in the effective spatial resolution for images without motion correction. Image error between undersampled and reference images was less than 10% for reconstructions using 750 or more spokes, yielding a minimum acceptable scan time of approximately 4 s/slice during quiescent through plane motion.ConclusionsBy rejecting data corrupted by through-plane motion, and correcting data corrupted by in-plane translation, the proposed reconstruction framework accounts for common sources of motion artifact (gross fetal movement, maternal respiration, fetal cardiac contraction) to produce high quality images of the fetal heart.

Aerobic exercise during pregnancy and presence of fetal-maternal heart rate synchronization.

It has been shown that short-term direct interaction between maternal and fetal heart rates may take place and that this interaction is affected by the rate of maternal respiration. The aim of this study was to determine the effect of maternal aerobic exercise during pregnancy on the occurrence of fetal-maternal heart rate synchronization.MethodsIn 40 pregnant women at the 36th week of gestation, 21 of whom exercised regularly, we acquired 18 min. RR interval time series obtained simultaneously in the mothers and their fetuses from magnetocardiographic recordings. The time series of the two groups were examined with respect to their heart rate variability, the maternal respiratory rate and the presence of synchronization epochs as determined on the basis of synchrograms. Surrogate data were used to assess whether the occurrence of synchronization was due to chance.ResultsIn the original data, we found synchronization occurred less often in pregnancies in which the mothers had exercised regularly. These subjects also displayed higher combined fetal-maternal heart rate variability and lower maternal respiratory rates. Analysis of the surrogate data showed shorter epochs of synchronization and a lack of the phase coordination found between maternal and fetal beat timing in the original data.ConclusionThe results suggest that fetal-maternal heart rate coupling is present but generally weak. Maternal exercise has a damping effect on its occurrence, most likely due to an increase in beat-to-beat differences, higher vagal tone and slower breathing rates.

T2* relaxometry of fetal brain at 1.5 Tesla using a motion tolerant method.

The aim of this study was to determine T2* values for the fetal brain in utero and to compare them with previously reported values in preterm and term neonates. Knowledge of T2* may be useful for assessing brain development, brain abnormalities, and for optimizing functional imaging studies. Maternal respiration and unpredictable fetal motion mean that conventional multishot acquisition techniques used in adult T2* relaxometry studies are not practical. Single shot multiecho echo planar imaging was used as a rapid method for measuring fetal T2* by effectively freezing intra-slice motion. T2* determined from a sample of 24 subjects correlated negatively with gestational age with mean values of 220 ms (±45) for frontal white matter, 159 ms (±32) for thalamic gray matter, and 236 ms (±45) for occipital white matter. Fetal T2* values are higher than those previously reported for preterm neonates and decline with a consistent trend across gestational age. The data suggest that longer than usual echo times or direct T2* measurement should be considered when performing fetal fMRI to reach optimal BOLD sensitivity.

Resting State fMRI in the moving fetus: A robust framework for motion, bias field and spin history correction

There is growing interest in exploring fetal functional brain development, particularly with Resting State fMRI. However, during a typical fMRI acquisition, the womb moves due to maternal respiration and the fetus may perform large-scale and unpredictable movements. Conventional fMRI processing pipelines, which assume that brain movements are infrequent or at least small, are not suitable. Previous published studies have tackled this problem by adopting conventional methods and discarding as much as 40% or more of the acquired data.In this work, we developed and tested a processing framework for fetal Resting State fMRI, capable of correcting gross motion. The method comprises bias field and spin history corrections in the scanner frame of reference, combined with slice to volume registration and scattered data interpolation to place all data into a consistent anatomical space. The aim is to recover an ordered set of samples suitable for further analysis using standard tools such as Group Independent Component Analysis (Group ICA).We have tested the approach using simulations and in vivo data acquired at 1.5T. After full motion correction, Group ICA performed on a population of 8 fetuses extracted 20 networks, 6 of which were identified as matching those previously observed in preterm babies.

Empirical Mode Decomposition of simulated and real ultrasonic Doppler signals of periodic fetal activity

Simulated signals comprising components (trains of Gaussian packets) resulting from cardiac movements and from pseudorespiratory movements with added white noise were submitted to Empirical Mode Decomposition. The increase of sampling frequency fs (from 0.5kHz to 5kHz) for given signal to noise ratio SNR moves signal components toward higher order intrinsic mode functions (IMFs) and increases their number. The increase of the SNR (from −5dB to 10dB, fixed fs) moves the signal components to lower order IMFs. The separation of components is most efficient for SNR≥5dB and fs not exceeding 1kHz, for lower SNRs fs should be at least 2kHz. SNR=∞ results in erroneous decomposition and therefore limited noise level is beneficial. Recommended number of sifting iterations is 10. Fetal data obtained using 2MHz emission frequency and sampled at 2kHz were decomposed. The cardiac signal always appears in IMF3, frequently also in IMF1 and IMF2. The pseudobreathing signal, appearing mainly in IMF4-6, is easy to separate. Signals resulting from fetal displacements due to maternal respiration appear in IMF7 or IMF8. The EMD performs better than the classic linear filtering as a tool for separation of the pseudorespiration signals and provides inferior results in terms of separation of the cardiac signals.

Towards improving uterine electrical activity modeling and electrohysterography: ultrasonic quantification of uterine movements during labor

The electrohysterogram is a potential new tool for diagnosing preterm labor. Parameters from the electrohysterogram may be influenced by uterine movement. An observational study was performed quantifying uterine movement during labor as a step towards improving electrohysterogram analysis for predicting preterm labor. The uterine wall was continuously tracked by ultrasound imaging during first stage of labor while an accelerometer recorded external abdominal accelerations in six women. A cyclic cranial-caudal movement of the uterine wall, caused by maternal respiration, was observed. This is reported and quantified for the first time. Average frequency, amplitude, and peak speed were 0.27±0.07Hz, 0.68±0.84cm, and 1.04±1.20cm/s, respectively. The accelerometer signal correlated with uterine movement and therefore can possibly provide a reference for removing movement-induced artifacts. There is a need to model and measure the effect of uterine movement on the electrohysterogram parameters and make measurements more robust to movement artifacts.

Fetal maternal heart rate entrainment under controlled maternal breathing

Event Abstract Back to Event Fetal maternal heart rate entrainment under controlled maternal breathing Peter V. Leeuwen1*, Daniel Geue2, Marko Thiel3, Silke Lange1, Mamen Romano3, Jürgen Kurths4 and Dietrich H. Grönemeyer1 1 University of Witten / Herdecke, Dept. of Radiology / Microtherapy, Germany 2 VISUS Technology Transfer, Department of Psychology, Faculty of Arts and Sciences, Germany 3 University of Aberdeen, Department of Physics, United Kingdom 4 Potsdam Institute for Climate Impact Research, Department of Psychology, Faculty of Arts and Sciences, Germany There is evidence that, during pregnancy, fetal and maternal cardiac activity may coordinate over short periods of time. Aim of this work was to investigate whether controlled paced maternal respiration has an effect on the occurrence of fetal-maternal heart rate synchronization. In 6 healthy pregnant women (34th - 40th week of gestation) we obtained simultaneous 5 min. fetal and maternal magnetocardiograms (MCG) at maternal respiration rates of 10, 12, 15 and 20 cpm as well as under spontaneous breathing. Fetal and maternal RR interval time series were constructed for each MCG data set and synchrograms were obtained using the stroboscopic technique. Synchronization epochs (SE) >10s were identified in these original data. Furthermore, "twin surrogate" data sets of the maternal MCG were constructed, combined with the fetal MCG data and SE were identified in these surrogate data. In the original data, there was a higher number of SE found at 20 cpm respiratory rate compared to other rates. This was not evident in the surrogate data. Fewer SE were found at lower rates (10 cpm) both in the original and surrogate data. Examination of the phase of fetal R peaks relative to maternal RR cycles showed that in the original data there was a clear phase preference in the 20 cpm data. This preference was not found in the surrogate data. These results were reproduced on the basis of a mathematical model incorporating the essential elements of fetal and maternal heart rates and their variability. We conclude that fetal-maternal heart rate entrainment may be induced by high maternal respiratory rates and that chance fetal-maternal heart rate coordination may be inhibited by low maternal respiratory rates. Conference: Biomag 2010 - 17th International Conference on Biomagnetism , Dubrovnik, Croatia, 28 Mar - 1 Apr, 2010. Presentation Type: Poster Presentation Topic: Fetal and neonatal biomagnetism Citation: Leeuwen PV, Geue D, Thiel M, Lange S, Romano M, Kurths J and Grönemeyer DH (2010). Fetal maternal heart rate entrainment under controlled maternal breathing. Front. Neurosci. Conference Abstract: Biomag 2010 - 17th International Conference on Biomagnetism . doi: 10.3389/conf.fnins.2010.06.00099 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 23 Mar 2010; Published Online: 23 Mar 2010. * Correspondence: Peter V Leeuwen, University of Witten / Herdecke, Dept. of Radiology / Microtherapy, Herdecke, Germany, sci@van-leeuwen.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Peter V Leeuwen Daniel Geue Marko Thiel Silke Lange Mamen Romano Jürgen Kurths Dietrich H Grönemeyer Google Peter V Leeuwen Daniel Geue Marko Thiel Silke Lange Mamen Romano Jürgen Kurths Dietrich H Grönemeyer Google Scholar Peter V Leeuwen Daniel Geue Marko Thiel Silke Lange Mamen Romano Jürgen Kurths Dietrich H Grönemeyer PubMed Peter V Leeuwen Daniel Geue Marko Thiel Silke Lange Mamen Romano Jürgen Kurths Dietrich H Grönemeyer Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Über den Einfluss der mütterlichen Atmung auf den Säure-Basen-Haushalt des Fetus sub partu - Versuch einer Quantifizierung

Hintergrund: Angst und Schmerz bestimmen das Atmungsverhalten und den Muskeltonus der werdenden Mutter unter der Geburt. Eine adäquate Atmung in der Austreibungs- und Pressperiode wirkt sich schmerzlindernd aus und fördert die Entspannung - auch der glatten Muskulatur. Mutter und Kind sind bis zur Geburt eine funktionelle Einheit. Unter bestimmten Bedingungen ist das Atmungsverhalten der Mutter an den aktuellen Blutgasen (pCO2 und O2) und ihr Muskeltonus am BE des Fetus im NV-Blut direkt ablesbar. In dieser Studie wird der Versuch unternommen, diese Zusammenhänge darzustellen, zu quantifizieren und in ihrer forensisch-klinischen Bedeutung zu evaluieren. Methodik: Bei 101 Patientinnen unterschiedlicher Parität wurden genau zum Zeitpunkt der Geburt arterielle Blutgasanalysen (Art. radialis) gemacht und der SB-Status im NA- und NV-Blut bestimmt. Unabhängig davon wurde bei 453 Feten von Müttern unterschiedlicher Parität das direkt abgeleitete CTG während der letzten 30 Minuten ante partum elektronisch (CTG-Score) analysiert. 60 dieser Feten wiesen eine minimale CTG-Pathologie auf (Score = 0). Die blutgasanalytischen Werte im NV-Blut dieser Feten dienten als „Spiegel“ der mütterlichen Einflüsse. In einer weiteren, separaten Stichprobe von 4853 Feten, die unter „Standardbedingungen“ in völlig lebensfrischem Zustand (Apgar 1 min: 9/10) spontan und termingerecht zur Welt gekommen waren, wurden die blutgasanalytischen Daten in Abhängigkeit von der Parität analysiert. Die durch die mütterlichen Einflüsse (Atmung und Muskelarbeit) verursachte, physiologische Variabilität der pH-Werte im NV- und NA-Blut wurde aus den Absolutkonzentrationen der H+-Ionen (cH+), also über die Numeri, ermittelt (nmol/l) und dann in pH-Werte zurückgerechnet. Der BE wurde über den pHqu40 und das pCO2 über den pHnm (non metabolic pH) ebenfalls in cH+ transformiert; so konnte die Zusammensetzung der fetalen Gesamtazidität (cH+) und damit das Ausmaß (%) der „Transfusionsazidose“ und der „Hyperventilationsalkalose“ im NV-Blut quantifiziert werden. Ergebnisse: Der mediane, art. pH der Mutter betrug 7,419, Range: 7,302 - 7,590 (Mittel: 7,425 ± 0,058). Die arteriellen pCO2-Werte bei der Mutter lagen zum Zeitpunkt der Geburt median bei 23,3 mmHg (Mittelwert 22,8 ± 4,7 mmHg). Der kleinste Wert betrug 11,6 der höchste 32,0 mmHg. Ihr BE betrug median -7,6 mmol/l. Zwischen den pCO2-Werten im art. Blut der Mutter und den pCO2-Werten im NV-Blut besteht eine hochsignifikante Korrelation (r = 0,514, p < 10-4). Analoges gilt für den BE bei Mutter und Kind (NV-Blut): r = 0,521, p < 10-4. Je höher die Parität umso tiefer liegen die pCO2- und umso höher die pH-Werte und der BE im NV-Blut. Die Differenzen sind für alle fetalen Parameter hoch signifikant (p << 10-4). Jenseits der III-Parität sind statistisch keine Veränderungen mehr fassbar. Selektioniert man die Fälle anhand des (direkten) CTG (Score = 0) so liegt der mittlere pH-Wert im NV-Blut bei 7,397 ± 0,055. Diese Werte schwanken allerdings zwischen 7,290 und 7,514. Für das NA-Blut gilt: 7,316 ± 0,052, Range: 7,202 bis 7,455. Diese Variabilität in den pH-Werten ist mütterlichen Ursprungs. Nach Umrechnung der pH- in cH+-Werte ergibt sich eine Streubreite für cH+ von ± 25 % im NV- und von ± 28 % im NA-Blut; in pH-Werte zurückgerechnet resultiert daraus ein Streubereich von 0,154 Einheiten. Das Verhältnis (%) von respiratorischer und metabolischer Komponente im NV-Blut liegt median bei 46,6 zu 53,4 %, also 1,14; die Streubreite liegt allerdings zwischen 0,4 und 99,5 %. Die materno-fetale Transfusionsazidose beträgt anteilmäßig (%) median -5,5 % (im Mittel -7,6 ± 11,7 %), Range: -36,4 bis +12,7 % und die maternogene, fetale Hyperventilationsalkalose median 6,1 % (Mittel: 7,1 ± 5,6 %), Range: -2,4 bis 24,4 % der totalen fetalen cH+ (nmol/l) im NV-Blut. Schlussfolgerungen: Die mütterliche Hyperventilation sub partu ist deutlich stärker als bisher angenommen. Die Parität der werdenden Mutter spielt dabei eine entscheidende Rolle. Mütterliche Blutgase und BE determinieren den fetalen BE und die fetalen Blutgase im NV-Blut. Der mütterliche Einfluss führt (bei CTG-Score = 0) median zu einer Streubreite des akt. pH im NV-Blut von 0,154 Einheiten, sodass ein pH-Wert von 7,100 durch mütterliche Einflüsse zwischen 7,030 und 7,184 schwanken kann. In wissenschaftlichen Untersuchungen über die Aussagekraft des CTG und in forensischen Auseinandersetzungen (pH-Metrie, BE) muss dieser stets präsente Einfluss der Mutter stärker beachtet werden.

Performance comparison of independent component analysis algorithms for fetal cardiac signal reconstruction: a study on synthetic fMCG data

Independent component analysis (ICA) algorithms have been successfully used for signal extraction tasks in the field of biomedical signal processing. We studied the performances of six algorithms (FastICA, CubICA, JADE, Infomax, TDSEP and MRMI-SIG) for fetal magnetocardiography (fMCG). Synthetic datasets were used to check the quality of the separated components against the original traces. Real fMCG recordings were simulated with linear combinations of typical fMCG source signals: maternal and fetal cardiac activity, ambient noise, maternal respiration, sensor spikes and thermal noise. Clusters of different dimensions (19, 36 and 55 sensors) were prepared to represent different MCG systems. Two types of signal-to-interference ratios (SIR) were measured. The first involves averaging over all estimated components and the second is based solely on the fetal trace. The computation time to reach a minimum of 20 dB SIR was measured for all six algorithms. No significant dependency on gestational age or cluster dimension was observed. Infomax performed poorly when a sub-Gaussian source was included; TDSEP and MRMI-SIG were sensitive to additive noise, whereas FastICA, CubICA and JADE showed the best performances. Of all six methods considered, FastICA had the best overall performance in terms of both separation quality and computation times.