Safety of contrast-enhanced ultrasound using microbubbles in human pregnancy: A scoping review.

Introduction - Successful placentation is crucial for fetal development and maintaining a healthy pregnancy. Placental insufficiency can cause a variety of obstetric complications. Despite the many efforts to enhance diagnosing placental insufficiency, no imaging technique has proven satisfactory. A promising imaging technique is contrast-enhanced ultrasound (CEUS) using microbubbles which is proven capable of (micro)vascular imaging. Its use for placental vascularization assessment in human pregnancies remains constrained by limited evidence and safety concerns. This scoping review aims to demonstrate the safety of CEUS used in human pregnancy in the published literature to date. Material and methods - a systematic search using PubMed, Medline, Embase, and Cochrane databases was performed. All studies where contrast-enhanced ultrasound was used in pregnant humans were included. Studies, where there was a planned termination of pregnancy, were excluded. To assess the safety of CEUS during pregnancy, relevant outcomes were divided into the following three categories; fetal outcome, maternal outcome, and pregnancy and neonatal outcomes. Results - A total of 13 articles were included, in which 256 women received CEUS during pregnancy. No clinically significant maternal or fetal adverse events or negative pregnancy or neonatal outcomes associated with CEUS were described. Conclusions - Based on our findings, we consider expanding the knowledge of this promising diagnostic technique in the future, larger clinical studies safe and relevant.

Fetal strain and strain rate measured with speckle tracking echocardiography in maternal diabetes: systematic review.

INTRODUCTION: The aim of this systematic review and meta-analysis was to evaluate fetal cardiac function in fetuses of mothers with diabetes compared to those of mothers without diabetes using 2D-STE. METHODS: Embase, MEDLINE and CENTRAL were searched for observational studies on 2D-STE fetal left and right ventricular global longitudinal strain and strain rate that included singleton, non-anomalous pregnancies complicated by pregestational or gestational diabetes mellitus compared to uncomplicated pregnancies. The strain values were pooled per 4 weeks of gestation for meta-analysis using random-effects models. RESULTS: Fifteen studies met the criteria, including 990 fetuses of diabetic mothers and 1,645 control fetuses. The study design was cross-sectional in fourteen studies and longitudinal in one study. Gestational age, type of diabetes, ultrasound device and 2D-STE software varied between the studies. Glycemic control and type of treatment were often lacking. In fetuses of diabetic mothers versus healthy mothers, left ventricular strain was significantly decreased (7 studies), increased (1 study) or not significantly different (7 studies). Right ventricular strain was decreased (7 studies), increased (1 study) or not different (2 studies). Left ventricular strain rate was decreased (3 studies), increased (1 study) or not different (2 studies). Right ventricular strain rate was increased (1 study) or not different (2 studies). CONCLUSION: Fetuses of mothers with diabetes show evidence of systolic dysfunction, which is more visible in the right ventricle. Contradictory results are probably due to suboptimal study designs and variation in gestational age, diabetes severity, image acquisition and software. Large prospective longitudinal studies are needed to assess fetal myocardial function with 2D-STE in pregestational diabetes mellitus type 1 and 2 and gestational diabetes mellitus pregnancies. The influence of glycemic control, BMI and treatment should be evaluated.

Psychological Distress During Pregnancy and the Development of Pregnancy-Induced Hypertension: A Prospective Study.

OBJECTIVE: Pregnancy-induced hypertension (PIH) is associated with serious complications in both the mother and the unborn child. We examined the possible association between trajectories of maternal psychological distress symptoms and PIH separately in primiparous and multiparous women. METHODS: Pregnancy-specific negative affect (P-NA) and depressive symptoms were assessed prospectively at each trimester using the Tilburg Pregnancy Distress Scale pregnancy negative affect subscale (P-NA) and the Edinburgh Depression Scale (EDS). Data on PIH were collected from medical records. Growth mixture modeling analysis was used to identify trajectories of P-NA and EDS. The independent role of P-NA and EDS symptom trajectories on developing PIH was examined using multivariate logistic regression models. RESULTS: One hundred (7.6%) women developed PIH and were compared with 1219 women without hypertension or other complications during pregnancy. Three P-NA trajectories were identified: low stable (reference group; 90%), decreasing (5.2%), and increasing (4.8%). The latter two classes showed persistently and significantly higher P-NA symptoms during pregnancy compared with the reference group. In multiparous women, high P-NA scores (belonging to classes 2 and 3) were related to PIH (odds ratio [OR] = 6.91, 95% confidence interval [CI] = 2.26-21.2), independent of body mass index (OR = 1.17, 95% CI = 1.06-1.27) and previous PIH (OR = 14.82, 95% CI = 6.01-32.7). No associations between P-NA and PIH were found in primiparous women. EDS trajectories were not related to PIH in both primiparous and multiparous women. CONCLUSIONS: In multiparous women, persistently high levels of P-NA symptoms but not depressive symptoms were independently associated with development of PIH.

Intrapartum non-invasive electrophysiological monitoring: A prospective observational study.

INTRODUCTION: Doppler ultrasound cardiotocography is a non-invasive alternative that, despite its poor specificity, is often first choice for intrapartum monitoring. Doppler ultrasound suffers from signal loss due to fetal movements and is negatively correlated with maternal body mass index (BMI). Reported accuracy of fetal heart rate monitoring by Doppler ultrasound varies between 10.6 and 14.3 bpm and reliability between 62.4% and 73%. The fetal scalp electrode (FSE) is considered the reference standard for fetal monitoring but can only be applied after membranes have ruptured with sufficient cervical dilatation and is sometimes contra-indicated. A non-invasive alternative that overcomes the shortcomings of Doppler ultrasound, providing reliable information on fetal heart rate, could be the answer. Non-invasive fetal electrocardiography (NI-fECG) uses a wireless electrode patch on the maternal abdomen to obtain both fetal and maternal heart rate signals as well as an electrohysterogram. We aimed to validate a wireless NI-fECG device for intrapartum monitoring in term singleton pregnancies, by comparison with the FSE. MATERIAL AND METHODS: We performed a multicenter cross-sectional observational study at labor wards of 6 hospitals located in the Netherlands, Belgium, and Spain. Laboring women with a healthy singleton fetus in cephalic presentation and gestational age between 36 and 42 weeks were included. Participants received an abdominal electrode patch and FSE after written informed consent. Accuracy, reliability, and success rate of fetal heart rate readings were determined, using FSE as reference standard. Analysis was performed for the total population and measurement period as well as separated by labor stage and BMI class (≤30 and >30 kg/m2 ). RESULTS: We included a total of 125 women. Simultaneous registrations with NI-fECG and FSE were available in 103 women. Overall accuracy is -1.46 bpm and overall reliability 86.84%. Overall success rate of the NI-fECG is around 90% for the total population as well as for both BMI subgroups. Success rate dropped to 63% during second stage of labor, similar results are found when looking at the separate BMI groups. CONCLUSIONS: Performance measures of the NI-fECG device are good in the overall group and the separate BMI groups. Compared with Doppler ultrasound performance measures from the literature, NI-fECG is a more accurate alternative. Especially, when women have a higher BMI, NI-fECG performs well, resembling FSE performance measures.

Features of Heart Rate Variability Capture Regulatory Changes During Kangaroo Care in Preterm Infants.

OBJECTIVE: To determine whether heart rate variability (HRV) can serve as a surrogate measure to track regulatory changes during kangaroo care, a period of parental coregulation distinct from regulation within the incubator. STUDY DESIGN: Nurses annotated the starting and ending times of kangaroo care for 3 months. The pre-kangaroo care, during-kangaroo care, and post-kangaroo care data were retrieved in infants with at least 10 accurately annotated kangaroo care sessions. Eight HRV features (5 in the time domain and 3 in the frequency domain) were used to visually and statistically compare the pre-kangaroo care and during-kangaroo care periods. Two of these features, capturing the percentage of heart rate decelerations and the extent of heart rate decelerations, were newly developed for preterm infants. RESULTS: A total of 191 kangaroo care sessions were investigated in 11 preterm infants. Despite clinically irrelevant changes in vital signs, 6 of the 8 HRV features (SD of normal-to-normal intervals, root mean square of the SD, percentage of consecutive normal-to-normal intervals that differ by >50 ms, SD of heart rate decelerations, high-frequency power, and low-frequency/high-frequency ratio) showed a visible and statistically significant difference (P <.01) between stable periods of kangaroo care and pre-kangaroo care. HRV was reduced during kangaroo care owing to a decrease in the extent of transient heart rate decelerations. CONCLUSION: HRV-based features may be clinically useful for capturing the dynamic changes in autonomic regulation in response to kangaroo care and other changes in environment and state.

Which Factors Contribute to False-Positive, False-Negative, and Invalid Results in Fetal Fibronectin Testing in Women with Symptoms of Preterm Labor?

Objective We assessed the influence of external factors on false-positive, false-negative, and invalid fibronectin results in the prediction of spontaneous delivery within 7 days. Methods We studied symptomatic women between 24 and 34 weeks' gestational age. We performed uni- and multivariable logistic regression to estimate the effect of external factors (vaginal soap, digital examination, transvaginal sonography, sexual intercourse, vaginal bleeding) on the risk of false-positive, false-negative, and invalid results, using spontaneous delivery within 7 days as the outcome. Results Out of 708 women, 237 (33%) had a false-positive result; none of the factors showed a significant association. Vaginal bleeding increased the proportion of positive fetal fibronectin (fFN) results, but was significantly associated with a lower risk of false-positive test results (odds ratio [OR], 0.22; 95% confidence intervals [CI], 0.12-0.39). Ten women (1%) had a false-negative result. None of the investigated factors was significantly associated with a significantly higher risk of false-negative results. Twenty-one tests (3%) were invalid; only vaginal bleeding showed a significant association (OR, 4.5; 95% CI, 1.7-12). Conclusion The effect of external factors on the performance of qualitative fFN testing is limited, with vaginal bleeding as the only factor that reduces its validity.

Study protocol: PoPE-Prediction of Preterm delivery by Electrohysterography.

BACKGROUND: Traditional methods used for prediction of preterm delivery are subjective and inaccurate. The Electrohysterogram (EHG) and in particular the estimation of the EHG conduction velocity, is a relatively new promising method for detecting imminent preterm delivery. To date the analysis of the conduction velocity has relied on visual inspection of the signals. As a next step towards the introduction of EHG analysis as a clinical tool, we propose an automated method for EHG conduction velocity estimation for both the speed and direction of single spike propagation. METHODS/DESIGN: The study design will be an observational cohort study. 100 pregnant women, gestational age between 23 + 5 and 34 weeks, admitted for threatening preterm labor or preterm prelabor rupture of membranes, will be included. The length of the cervical canal will be measured by transvaginal ultrasound. The EHG will be recorded using 4 electrodes in a fixed configuration. Contractions will be detected by analysis of the EHG and using an estimation of the intra uterine pressure. In the selected contractions, the delays between channels will be estimated by cross-correlation, and subsequently, the average EHG conduction velocity will be derived. Patients will be classified as labor group and non-labor group based on the time between measurement and delivery. The average conduction velocity and cervical length will be compared between the groups. The main study endpoints will be sensitivity, specificity, and area under the ROC curve for delivery within 1,2,4,7, and 14 days from the measurement. DISCUSSION: In this study, the diagnostic accuracy of EHG conduction velocity analysis will be evaluated for detecting preterm labor. Visual and automatic detection of contractions will be compared. Planar wave propagation will be assumed for the calculation of the CV vector. TRIAL REGISTRATION: Current Controlled Trials ISRCTN07603227.

A simulation model to study maternal hyperoxygenation during labor.

OBJECTIVE: To investigate the effect of maternal hyperoxygenation on fetal oxygenation and fetal heart rate decelerations during labor, using a simulation model. DESIGN: Use of a mathematical model that simulates feto-maternal hemodynamics and oxygenation, designed in Matlab R2012a. SETTING: Clinical and engineering departments in the Netherlands. METHODS: We simulated variable and late fetal heart rate decelerations, caused by uterine contractions with a different contraction interval. We continuously recorded oxygen pressure in different feto-placental compartments and fetal heart rate, during maternal normoxia and during hyperoxygenation with 100% oxygen. MAIN OUTCOME MEASURES: Changes in oxygen pressure in the intervillous space, umbilical vein and arteries, fetal cerebral and microcirculation as well as fetal heart rate deceleration depth and duration. RESULTS: Maternal hyperoxygenation leads to an increase in fetal oxygenation: in the presence of variable decelerations, oxygen pressure in the intervillous space increased 9-10 mmHg and in the cerebral circulation 1-2 mmHg, depending on the contraction interval. In addition, fetal heart rate deceleration depth decreased from 45 to 20 beats per minute. In the presence of late decelerations, oxygen pressure in the intervillous space increased 7-10 mmHg and in the cerebral circulation 1-2 mmHg, depending on the contraction interval. The fetus benefited more from maternal hyperoxygenation when contraction intervals were longer. CONCLUSIONS: According to the simulation model, maternal hyperoxygenation leads to an increase in fetal oxygenation, especially in the presence of variable decelerations. In addition, in the presence of variable decelerations, maternal hyperoxygenation leads to amelioration of the fetal heart rate pattern.

Four countries, four ways of discussing low-risk pregnancy and normal delivery: in France, Germany, The Netherlands, and the United Kingdom.

The 2012 "4 countries meeting" of the French, Dutch, British and German Societies of Gynaecology and Obstetrics (CNGOF, NVOG, RCOG, DGGG) was dedicated to the topic "Low-risk pregnancy and normal delivery". The objective was to compare how each country organises prenatal care and normal delivery. The discussion is outlined in the article and provides new opportunities to learn from each other's strengths in order to provide the highest level of care regardless of social, demographic, educational and clinical differences.

The impact of transmural multiprofessional simulation-based obstetric team training on perinatal outcome and quality of care in the Netherlands.

BACKGROUND: Perinatal mortality and morbidity in the Netherlands is relatively high compared to other European countries. Our country has a unique system with an independent primary care providing care to low-risk pregnancies and a secondary/tertiary care responsible for high-risk pregnancies. About 65% of pregnant women in the Netherlands will be referred from primary to secondary care implicating multiple medical handovers. Dutch audits concluded that in the entire obstetric collaborative network process parameters could be improved. Studies have shown that obstetric team training improves perinatal outcome and that simulation-based obstetric team training implementing crew resource management (CRM) improves team performance. In addition, deliberate practice (DP) improves medical skills. The aim of this study is to analyse whether transmural multiprofessional simulation-based obstetric team training improves perinatal outcome. METHODS/DESIGN: The study will be implemented in the south-eastern part of the Netherlands with an annual delivery rate of over 9,000. In this area secondary care is provided by four hospitals. Each hospital with referring primary care practices will form a cluster (study group). Within each cluster, teams will be formed of different care providers representing the obstetric collaborative network. CRM and elements of DP will be implemented in the training. To analyse the quality of care as perceived by patients, the Pregnancy and Childbirth Questionnaire (PCQ) will be used. Furthermore, self-reported collaboration between care providers will be assessed. Team performance will be measured by the Clinical Teamwork Scale (CTS). We employ a stepped-wedge trial design with a sequential roll-out of the trainings for the different study groups.Primary outcome will be perinatal mortality and/or admission to a NICU. Secondary outcome will be team performance, quality of care as perceived by patients, and collaboration among care providers. CONCLUSION: The effect of transmural multiprofessional simulation-based obstetric team training on perinatal outcome has never been studied. We hypothesise that this training will improve perinatal outcome, team performance, and quality of care as perceived by patients and care providers. TRIAL REGISTRATION: The Netherlands National Trial Register, http://www.trialregister.nl/NTR4576, registered June 1, 2014.

Changes in Maternal Heart Rate Variability and Photoplethysmography Morphology after Corticosteroid Administration: A Prospective, Observational Study.

Background: Owing to the association between dysfunctional maternal autonomic regulation and pregnancy complications, assessing non-invasive features reflecting autonomic activity-e.g., heart rate variability (HRV) and the morphology of the photoplethysmography (PPG) pulse wave-may aid in tracking maternal health. However, women with early pregnancy complications typically receive medication, such as corticosteroids, and the effect of corticosteroids on maternal HRV and PPG pulse wave morphology is not well-researched. Methods: We performed a prospective, observational study assessing the effect of betamethasone (a commonly used corticosteroid) on non-invasively assessed features of autonomic regulation. Sixty-one women with an indication for betamethasone were enrolled and wore a wrist-worn PPG device for at least four days, from which five-minute measurements were selected for analysis. A baseline measurement was selected either before betamethasone administration or sufficiently thereafter (i.e., three days after the last injection). Furthermore, measurements were selected 24, 48, and 72 h after betamethasone administration. HRV features in the time domain and frequency domain and describing heart rate (HR) complexity were calculated, along with PPG morphology features. These features were compared between the different days. Results: Maternal HR was significantly higher and HRV features linked to parasympathetic activity were significantly lower 24 h after betamethasone administration. Features linked to sympathetic activity remained stable. Furthermore, based on the PPG morphology features, betamethasone appears to have a vasoconstrictive effect. Conclusions: Our results suggest that administering betamethasone affects maternal autonomic regulation and cardiovasculature. Researchers assessing maternal HRV in complicated pregnancies should schedule measurements before or sufficiently after corticosteroid administration.

Neurodevelopmental outcome at 5.5 years in Dutch preterm infants born at 24-26 weeks' gestational age: the EPI-DAF study.

OBJECTIVE: After lowering the Dutch threshold for active treatment from 25 to 24 completed weeks' gestation, survival to discharge increased by 10% in extremely preterm live born infants. Now that this guideline has been implemented, an accurate description of neurodevelopmental outcome at school age is needed. DESIGN: Population-based cohort study. SETTING: All neonatal intensive care units in the Netherlands. PATIENTS: All infants born between 240/7 and 266/7 weeks' gestation who were 5.5 years' corrected age (CA) in 2018-2020 were included. MAIN OUTCOME MEASURES: Main outcome measure was neurodevelopmental outcome at 5.5 years. Neurodevelopmental outcome was a composite outcome defined as none, mild or moderate-to-severe impairment (further defined as neurodevelopmental impairment (NDI)), using corrected cognitive score (Wechsler Preschool and Primary Scale of Intelligence Scale-III-NL), neurological examination and neurosensory function. Additionally, motor score (Movement Assessment Battery for Children-2-NL) was assessed. All assessments were done as part of the nationwide, standardised follow-up programme. RESULTS: In the 3-year period, a total of 632 infants survived to 5.5 years' CA. Data were available for 484 infants (77%). At 5.5 years' CA, most cognitive and motor (sub)scales were significantly lower compared with the normative mean. Overall, 46% had no impairment, 36% had mild impairment and 18% had NDI. NDI-free survival was 30%, 49% and 67% in live born children at 24, 25 and 26 weeks' gestation, respectively (p<0.001). CONCLUSIONS: After lowering the threshold for supporting active treatment from 25 to 24 completed weeks' gestation, a considerable proportion of the surviving extremely preterm children did not have any impairment at 5.5 years' CA.

Maternal thyroid function and the outcome of external cephalic version: a prospective cohort study.

BACKGROUND: To investigate the relation between maternal thyroid function and the outcome of external cephalic version (ECV) in breech presentation. METHODS: Prospective cohort study in 141 women (≥ 35 weeks gestation) with a singleton fetus in breech. Blood samples for assessing thyroid function were taken prior to ECV. Main outcome measure was the relation between maternal thyroid function and ECV outcome indicated by post ECV ultrasound. RESULTS: ECV success rate was 77/141 (55%), 41/48 (85%) in multipara and 36/93 (39%) in primipara. Women with a failed ECV attempt had significantly higher TSH concentrations than women with a successful ECV (p < 0.001). Multiple logistic regression showed that TSH (OR: 0.52, 95% CI: 0.30-0.90), nulliparity (OR: 0.11, 95% CI: 0.03-0.36), frank breech (OR: 0.30, 95% CI: 0.10-0.93) and placenta anterior (OR: 0.31, 95% CI: 0.11-0.85) were independently related to ECV success. CONCLUSIONS: Higher TSH levels increase the risk of ECV failure. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov: NCT00516555.

Cost-effectiveness of cardiotocography plus ST analysis of the fetal electrocardiogram compared with cardiotocography only.

OBJECTIVE: To assess the cost-effectiveness of addition of ST analysis of the fetal electrocardiogram (ECG; STAN) to cardiotocography (CTG) for fetal surveillance during labor compared with CTG only. DESIGN: Cost-effectiveness analysis based on a randomized clinical trial on ST analysis of the fetal ECG. SETTING: Obstetric departments of three academic and six general hospitals in The Netherlands. Population. Laboring women with a singleton high-risk pregnancy, a fetus in cephalic presentation, a gestational age >36 weeks and an indication for internal electronic fetal monitoring. METHODS: A trial-based cost-effectiveness analysis was performed from a health-care provider perspective. MAIN OUTCOME MEASURES: Primary health outcome was the incidence of metabolic acidosis measured in the umbilical artery. Direct medical costs were estimated from start of labor to childbirth. Cost-effectiveness was expressed as costs to prevent one case of metabolic acidosis. RESULTS: The incidence of metabolic acidosis was 0.7% in the ST-analysis group and 1.0% in the CTG-only group (relative risk 0.70; 95% confidence interval 0.38-1.28). Per delivery, the mean costs per patient of CTG plus ST analysis (n= 2 827) were €1,345 vs. €1,316 for CTG only (n= 2 840), with a mean difference of €29 (95% confidence interval -€9 to €77) until childbirth. The incremental costs of ST analysis to prevent one case of metabolic acidosis were €9 667. CONCLUSIONS: The additional costs of monitoring by ST analysis of the fetal ECG are very limited when compared with monitoring by CTG only and very low compared with the total costs of delivery.

Implementation of simulation in surgical practice: minimally invasive surgery has taken the lead: the Dutch experience.

Minimal invasive techniques are rapidly becoming standard surgical techniques for many surgical procedures. To develop the skills necessary to apply these techniques, box trainers and/or inanimate models may be used, but these trainers lack the possibility of inherent objective classification of results. In the past decade, virtual reality (VR) trainers were introduced for training minimal invasive techniques. Minimally invasive surgery (MIS) is, by nature, very suitable for this type of training. The specific psychomotor skills and eye-hand coordination needed for MIS can be mastered largely using VR simulation techniques. It is also possible to transfer skills learned on a simulator to real operations, resulting in error reduction and shortening of procedural operating time. The authors aim to enlighten the process of gaining acceptance in the Netherlands for novel training techniques. The Dutch Societies of Surgery, Obstetrics and Gynecology, and Urology each developed individual training curricula for MIS using simulation techniques, to be implemented in daily practice. The ultimate goal is to improve patient safety. The authors outline the opinions of actors involved, such as different simulators, surgical trainees, surgeons, surgical societies, hospital boards, government, and the public. The actual implementation of nationwide training curricula for MIS is, however, a challenging step.

The Brabant study: design of a large prospective perinatal cohort study among pregnant women investigating obstetric outcome from a biopsychosocial perspective.

BACKGROUND: Pregnancy is characterised by many biological and psychosocial changes. Adequate maternal thyroid function is important for the developing fetus throughout gestation. Latent class analyses recently showed three different patterns of change in thyroid function throughout pregnancy with different associations with obstetric outcome. Maternal distress during the pregnancy (anxiety and depression) negatively affects obstetric outcome. Pregnancy distress in turn may be affected by personality traits and attachment styles. Moreover, during the pregnancy, substantial social changes occur in the partner relationship and work experience. The aim of the Brabant study is to investigate the association between thyroid function trajectories and obstetric outcomes. Moreover, within the Brabant study, we will investigate how different trajectories of pregnancy distress are related to obstetric outcome, and the role of personality in this association. We will evaluate the possible role of maternal distress and attachment style on maternal-fetal bonding. Finally, we will study social changes in the perinatal period regarding partner relationship and well-being and performance at work. METHODS AND ANALYSIS: The Brabant study is a longitudinal, prospective cohort study of an anticipated 4000 pregnant women. Women will be recruited at 8-10 weeks gestation among community midwife practices in South-East Brabant in the Netherlands. Thyroid function parameters (TSH and fT4), thyroid peroxidase antibody and human chorionic gonadotrophin will be assessed at 12, 20 and 28 weeks gestation. Moreover, at these three time points women will fill out questionnaires assessing demographic and obstetric features, life style habits and psychological and social variables, such as depressive symptoms, personality, partner relationship quality and burnout. Data from the obstetric records will also be collected. ETHICS AND DISSEMINATION: The study has been approved by the Medical Ethical Committee of the Máxima Medical Center Veldhoven. Results will be submitted to peer-reviewed journals in the relevant fields and presented on national and international conferences.

Inter-electrode delay estimators for electrohysterographic propagation analysis.

Premature birth is a major cause of mortality and permanent dysfunctions. Several parameters derived from single channel electrohysterographic (EHG) signals have been considered to determine contractions leading to preterm delivery. The results are promising, but improvements are needed. As effective uterine contractions result from a proper action potential propagation, in this paper we focus on the propagation properties of EHG signals, which can be predictive of preterm delivery. Two standard delay estimators, namely maximization of the cross-correlation function and spectral matching, are adapted and implemented for the assessment of inter-electrode delays of propagating EHG signals. The accuracy of the considered standard estimators might be hampered by a poor inter-channel correlation. An improved dedicated approach is therefore proposed. By simultaneous adaptive estimation of the volume conductor transfer function and the delay, a dedicated method is conceived for improving the inter-channel signal similarity during delay calculation. Furthermore, it provides delay estimates without resolution limits and it is suitable for low sampling rates, which are appropriate for EHG recording. The three estimators were evaluated on EHG signals recorded on seven women. The dedicated approach provided more accurate estimates due to a 22% improvement of the initial average inter-channel correlation.

Burnout in medical residents: a questionnaire and interview study.

High burnout levels have been observed in medical residents. The purpose of this study is to assess the burnout rates and potential determinants of burnout in a sample of medical residents. In total, 58 medical residents working in a Dutch teaching hospital, received questionnaires at home, including the Maslach Burnout Inventory (MBI). In addition, they were asked for an in-depth interview to investigate the relevant indicators for developing burnout. In total, 47 residents responded (81%) from which 15 (31%) met the MBI criteria for burnout. Work-family conflict, work-related autonomy and level of work-engagement were significantly associated with burnout. Ten respondents were interviewed; none of those reported any serious burnout symptoms but two met the criteria for burnout. In this study, burnout rates from questionnaires and interviews in medical residents are not consistent. Regular burnout screenings and performing interviews are recommended in addition to burnout questionnaires, in order to efficiently identify residents at risk for burnout. This allows improved monitoring of a resident's mental state thus facilitating prevention of escalating burnout symptoms. Future research could focus on preventive factors for developing burnout.

Estimation of internal uterine pressure by joint amplitude and frequency analysis of electrohysterographic signals.

Monitoring the uterine contraction provides important prognostic information during pregnancy and parturition. The existing methods employed in clinical practice impose a compromise between reliability and invasiveness. A promising technique for uterine contraction monitoring is electrohysterography (EHG). The EHG signal measures the electrical activity which triggers the contraction of the uterine muscle. In this paper, a non-invasive method for intrauterine pressure (IUP) estimation by EHG signal analysis is proposed. The EHG signal is regarded as a non-stationary signal whose frequency and amplitude characteristics are related to the IUP. After acquisition in a multi-channel configuration, the EHG signal is therefore analyzed in the time-frequency domain. A first estimation of the IUP is then derived by calculation of the unnormalized first statistical moment of the frequency spectrum. The estimation accuracy is finally increased by identification of a second-order polynomial model. The proposed method is compared to root mean squared analysis and optimal linear filtering and validated by simultaneous measurement of the IUP on nine women during labor. The results suggest that the proposed EHG signal analysis provides an accurate estimate of the IUP.

Unlike Kangaroo care, mechanically simulated Kangaroo care does not change heart rate variability in preterm neonates.

BACKGROUND: While numerous positive effects of Kangaroo care (KC) have been reported, the duration that parents can spend kangarooing is often limited. AIM: To investigate whether a mattress that aims to mimic breathing motion and the sounds of heartbeats (BabyBe GMBH, Stuttgart, Germany) can simulate aspects of KC in preterm infants as measured by features of heart rate variability (HRV). METHODS: A within-subject study design was employed in which every routine KC session was followed by a BabyBe (BB) session, with a washout period of at least 2 h in between. Nurses annotated the start and end times of KC and BB sessions. Data from the pre-KC, KC, post-KC, pre-BB, BB and post-BB were retrieved from the patient monitor via a data warehouse. Five time-domain features of HRV were used to compare both types of intervention. Two of these features, the percentage of decelerations (pDec) and the standard deviation of decelerations (SDDec), were developed in a previous study to capture the contribution of transient heart rate decelerations to HRV, a measure of regulatory instability. RESULTS: A total of 182 KC and 180 BabyBe sessions were analyzed in 20 preterm infants. Overall, HRV decreased during KC and after KC. Two of the five features showed a decrease during KC, and all features decreased in the post-KC period (p ≤ 0.01). The BB mattress as employed in this study did not affect HRV. CONCLUSION: Unlike KC, a mattress that attempts to mimic breathing motion and heartbeat sounds does not affect HRV of preterm infants.