Early prediction of gestational diabetes mellitus using maternal demographic and clinical risk factors

OBJECTIVE

To build and validate an early risk prediction model for gestational diabetes mellitus (GDM) based on first-trimester electronic medical records including maternal demographic and clinical risk factors.

METHODS

To develop and validate a GDM prediction model, two datasets were used in this retrospective study. One included data of 14,015 pregnant women from Máxima Medical Center (MMC) in the Netherlands. The other was from an open-source database nuMoM2b including data of 10,038 nulliparous pregnant women, collected in the USA. Widely used maternal demographic and clinical risk factors were considered for modeling. A GDM prediction model based on elastic net logistic regression was trained from a subset of the MMC data. Internal validation was performed on the remaining MMC data to evaluate the model performance. For external validation, the prediction model was tested on an external test set from the nuMoM2b dataset.

RESULTS

An area under the receiver-operating-characteristic curve (AUC) of 0.81 was achieved for early prediction of GDM on the MMC test data, comparable to the performance reported in previous studies. While the performance markedly decreased to an AUC of 0.69 when testing the MMC-based model on the external nuMoM2b test data, close to the performance trained and tested on the nuMoM2b dataset only (AUC = 0.70).

Transferring an extremely premature infant to an extra-uterine life support system: a prospective view on the obstetric procedure

To improve care for extremely premature infants, the development of an extrauterine environment for newborn development is being researched, known as Artificial Placenta and Artificial Womb (APAW) technology. APAW facilitates extended development in a liquid-filled incubator with oxygen and nutrient supply through an oxygenator connected to the umbilical vessels. This setup is intended to provide the optimal environment for further development, allowing further lung maturation by delaying gas exposure to oxygen. This innovative treatment necessitates interventions in obstetric procedures to transfer an infant from the native to an artificial womb, while preventing fetal-to-neonatal transition. In this narrative review we analyze relevant fetal physiology literature, provide an overview of insights from APAW studies, and identify considerations for the obstetric procedure from the native uterus to an APAW system. Lastly, this review provides suggestions to improve sterility, fetal and maternal well-being, and the prevention of neonatal transition.

Detection of postpartum uterine activity with electrohysterography

OBJECTIVE

Uterine contractions are essential for childbirth, but also for expulsion of the placenta and for limiting postpartum blood loss. Postpartum hemorrhage is associated with almost 25% of the maternal deaths worldwide and the leading cause of maternal death in most low-income countries. Little is known about the physiology of the uterus postpartum, particularly due to the lack of an accurate measurement tool. The primary objective of this pilot study is to explore the potential of using electrohysterography to detect postpartum uterine contractions. If postpartum uterine activity can be objectified, this could contribute to understanding the physiology of the uterus and improve diagnosis and treatment of postpartum hemorrhage.

STUDY DESIGN

In this observational study we included women aiming for a vaginal birth in two large maternity clinics in the Netherlands, Amphia Hospital Breda (group A, N2018-0161) and Máxima Medical Center Veldhoven (group B, N17.149). An electrode patch was placed on the maternal abdomen to record real-time electrical uterine activity until one hour postpartum continuously. In group A, the placement of the patch was lower than in group B. For analysis, tracings were divided into five different phases (1: dilatation until start pushing, 2: from start pushing until childbirth, 3: from childbirth until placental expulsion, 4: first hour after placental expulsion and 5: after one hour postpartum). Readability, signal quality and contraction frequency per hour were assessed. Additionally, patient satisfaction was evaluated through a survey.

RESULTS

In total 91 pregnant women were included of whom 45 in group A and 46 women in group B. Complete registrations were obtained throughout the five labor phases with very little artefacts or signal loss. The readability of the tracings decreased after childbirth. A significantly better readability was found in tracings where the patch placement was lower on the abdomen for phases 4 and 5. Contraction frequency was highest during phase 2 and decreased towards phase 5. Women rated the satisfaction with electrohysterography as high and mostly did not notice the patch.

CONCLUSION

It is possible to detect uterine activity postpartum with electrohysterography. Further investigation is recommended to improve diagnosis and treatment of postpartum hemorrhage.

Visualization of contractions: Evaluation of a new experience design concept to enhance the childbirth experience

BACKGROUND

The purpose of this study was to develop and evaluate an innovative design proposition intended to help enhance the childbirth experience. The innovation consists of a smartphone application for birth preparation during pregnancy with information and coaching, in addition to a wall projection at the labor ward that visualizes the progress of labor based on uterine monitoring data.

METHODS

We conducted a randomized controlled clinical pilot study. Singleton pregnant people pursuing a vaginal birth were recruited between 28 and 32 weeks of gestation and allocated to the intervention group (mobile application during the third trimester and wall projection at the labor ward) or to care as usual. Childbirth expectations and experiences were measured with validated questionnaires, which were completed at 32 and 36 weeks of gestation, immediately after birth, and at 4 weeks postpartum. Quantitative outcomes were analyzed and feedback about the proposition was evaluated using qualitative methods.

RESULTS

The qualitative feedback from patients was largely positive; however, we could not detect any significant differences between the intervention and control groups about fear of childbirth and other outcome measures.

CONCLUSION

In this pilot study, we evaluated a new experience design proposition for pregnancy and childbirth. This study generated data that will help to further improve and evaluate similar innovations in the future. This application may facilitate participatory care, promoting active involvement of parents in the healthcare processes of pregnancy and childbirth.

Simulation-Based Training in Emergency Obstetric Care in Sub-Saharan and Central Africa: A Scoping Review

Background

Every day approximately 810 women die from complications related to pregnancy and childbirth worldwide. Around two thirds of these deaths happen in sub-Saharan Africa. One of the strategies to decrease these numbers is improving the quality of care by emergency obstetric simulation-based training. The effectiveness of such training programs depends on the program's instructional design.

Objective

This review gives an overview of studies about emergency obstetric simulation-based training and examines the applied instructional design of the training programs in sub-Saharan and Central Africa.

Methods

We searched Medline, Embase and Cochrane Library from inception to May 2021. Peer-reviewed articles on emergency obstetric, postgraduate, simulation-based training in sub-Saharan and Central Africa were included. Outcome measures were categorized based on Kirkpatrick's levels of training evaluation. The instructional design was evaluated by using the ID-SIM questionnaire.

Findings

In total, 47 studies met the inclusion criteria. Evaluation on Kirkpatrick level 1 showed positive reactions in 18 studies. Challenges and recommendations were considered. Results on knowledge, skills, and predictors for these results (Kirkpatrick level 2) were described in 29 studies. Retention as well as decay of knowledge and skills over time were presented. Results at Kirkpatrick level 3 were measured in 12 studies of which seven studies demonstrated improvements of skills on-the-job. Improvements of maternal and neonatal outcomes were described in fifteen studies and three studies reported on cost-estimations for training rollout (Kirkpatrick level 4). Instructional design items were heterogeneously applied and described.

Conclusions

Results of 47 studies indicate evidence that simulation-based training in sub-Saharan and Central Africa can have a positive impact across all four levels of Kirkpatrick's training evaluation model. However, results were not consistent across all studies and the effects vary over time. A detailed description of instructional design features in future publications on simulation-based training will contribute to a deeper understanding of the underlying mechanisms that determine why certain training programs are more effective in improving maternal and neonatal healthcare outcomes than other.

Interprofessional Consensus Regarding Design Requirements for Liquid-Based Perinatal Life Support (PLS) Technology

Liquid-based perinatal life support (PLS) technology will probably be applied in a first-in-human study within the next decade. Research and development of PLS technology should not only address technical issues, but also consider socio-ethical and legal aspects, its application area, and the corresponding design implications. This paper represents the consensus opinion of a group of healthcare professionals, designers, ethicists, researchers and patient representatives, who have expertise in tertiary obstetric and neonatal care, bio-ethics, experimental perinatal animal models for physiologic research, biomedical modeling, monitoring, and design. The aim of this paper is to provide a framework for research and development of PLS technology. These requirements are considering the possible respective user perspectives, with the aim to co-create a PLS system that facilitates physiological growth and development for extremely preterm born infants.

A review study of fetal circulatory models to develop a digital twin of a fetus in a perinatal life support system

BACKGROUND

Preterm birth is the main cause of neonatal deaths with increasing mortality and morbidity rates with decreasing GA at time of birth. Currently, premature infants are treated in neonatal intensive care units to support further development. However, the organs of, especially, extremely premature infants (born before 28 weeks of GA) are not mature enough to function optimally outside the womb. This is seen as the main cause of the high morbidity and mortality rates in this group. A liquid-filled incubator, a so-called PLS system, could potentially improve these numbers for extremely premature infants, since this system is designed to mimic the environment of the natural womb. To support the development and implementation of such a complex system and to interpret vital signals of the fetus during a PLS system operation, a digital twin is proposed. This mathematical model is connected with a manikin representing the digital and physical twin of the real-life PLS system. Before developing a digital twin of a fetus in a PLS system, its functional and technical requirements are defined and existing mathematical models are evaluated.

METHOD AND RESULTS

This review summarizes existing 0D and 1D fetal circulatory models that potentially could be (partly) adopted for integration in a digital twin of a fetus in a PLS system based on predefined requirements. The 0D models typically describe hemodynamics and/or oxygen transport during specific events, such as the transition from fetus to neonate. Furthermore, these models can be used to find hemodynamic differences between healthy and pathological physiological states. Rather than giving a global description of an entire cardiovascular system, some studies focus on specific organs or vessels. In order to analyze pressure and flow wave profiles in the cardiovascular system, transmission line or 1D models are used. As for now, these models do not include oxygen transport.

CONCLUSION

This study shows that none of the models identified in literature meet all the requirements relevant for a digital twin of a fetus in a PLS system. Nevertheless, it does show the potential to develop this digital twin by integrating (parts) of models into a single model.

Evaluating the Instructional Design and Effect on Knowledge, Teamwork, and Skills of Technology-Enhanced Simulation-Based Training in Obstetrics in Uganda: Stepped-Wedge Cluster Randomized Trial

BACKGROUND

Simulation-based training is a common strategy for improving the quality of facility-based maternity services and is often evaluated using Kirkpatrick's theoretical model. The results on the Kirkpatrick levels are closely related to the quality of the instructional design of a training program. The instructional design is generally defined as the "set of prescriptions for teaching methods to improve the quality of instruction with a goal of optimizing learning outcomes."

OBJECTIVE

The aim of this study is to evaluate the instructional design of a technology-enhanced simulation-based training in obstetrics, the reaction of participants, and the effect on knowledge, teamwork, and skills in a low-income country.

METHODS

A stepped-wedge cluster randomized trial was performed in a university hospital in Kampala, Uganda, with an annual delivery volume of over 31,000. In November 2014, a medical simulation center was installed with a full-body birthing simulator (Noelle S550, Gaumard Scientific), an interactive neonate (Simon S102 Newborn CPR Simulator, Gaumard Scientific), and an audio and video recording system. Twelve local obstetricians were trained and certified as medical simulation trainers. From 2014 to 2016, training was provided to 57 residents in groups of 6 to 9 students. Descriptive statistics were calculated for ten instructional design features of the training course measured by the 42-item ID-SIM (Instructional Design of a Simulation Improved by Monitoring). The Wilcoxon signed rank test was conducted to investigate the differences in scores on knowledge, the Clinical Teamwork Scale, and medical technical skills.

RESULTS

The mean scores on the ten instructional design features ranged from 54.9 (95% CI 48.5-61.3) to 84.3 (95% CI 80.9-87.6) out of 100. The highest mean score was given on the feature feedback and the lowest scores on repetitive practice and controlled environment. The overall score for the training day was 92.8 out of 100 (95% CI 89.5-96.1). Knowledge improved significantly, with a test score of 63.4% (95% CI 60.7-66.1) before and 78.9% (95% CI 76.8-81.1) after the training (P<.001). The overall score on the 10-point Clinical Teamwork Scale was 6.0 (95% CI 4.4-7.6) before and 5.9 (95% CI 4.5-7.2) after the training (P=.78). Medical technical skills were scored at 55.5% (95% CI 47.2-63.8) before and 65.6% (95% CI 56.5-74.7) after training (P=.08).

CONCLUSIONS

Most instructional design features of a technology-enhanced simulation-based training in obstetrics in a low-income country were scored high, although intervals were large. The overall score for the training day was high, and knowledge did improve after the training program, but no changes in teamwork and (most) medical technical skills were found. The lowest-scored instructional design features may be improved to achieve further learning aims.

TRIAL REGISTRATION

ISRCTN Registry ISRCTN98617255; http://www.isrctn.com/ISRCTN98617255.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR2-10.1186/s12884-020-03050-3.

Changes in Maternal Heart Rate Variability in Response to the Administration of Routine Obstetric Medication in Hospitalized Patients: Study Protocol for a Cohort Study (MAMA-Heart Study)

Pregnancy is a period of continuous change in the maternal cardiovascular system, partly mediated by the autonomic nervous system. Insufficient autonomic adaptation to increasing gestation is associated with pregnancy complications, such as hypertensive disorders of pregnancy and preterm birth (both major causes of perinatal morbidity and mortality). Consequently, maternal heart rate variability (mHRV), which is a proxy measure for autonomic activity, is increasingly assessed in these cohorts to investigate the pathophysiology of their complications. A better pathophysiological understanding could facilitate the early detection of these complications, which remains challenging. However, such studies (typically performed in pregnancies leading to hospitalization) have generated conflicting findings. A probable reason for these conflicting findings is that these study cohorts were likely administered routine obstetric medications during the study period of which the effects on mHRV are largely unknown. Subsequently, we design a longitudinal, observational study to quantifying the effect of these medications-particularly corticosteroids, which are known to affect fetal HRV-on mHRV to improve the interpretation of past and future studies. We will enroll 61 women admitted to a tertiary obstetric unit with an indication to receive corticosteroids antenatally. Participants' mHRV will be continuously acquired throughout their hospitalization with wrist-worn photoplethysmography to facilitate a within-patient comparison of the effect of corticosteroids on mHRV.

Ethical Development of Artificial Amniotic Sac and Placenta Technology: A Roadmap

In this paper we present an initial roadmap for the ethical development and eventual implementation of artificial amniotic sac and placenta technology in clinical practice. We consider four elements of attention: (1) framing and societal dialogue; (2) value sensitive design, (3) research ethics and (4) ethical and legal research resulting in the development of an adequate moral and legal framework. Attention to all elements is a necessary requirement for ethically responsible development of this technology. The first element concerns the importance of framing and societal dialogue. This should involve all relevant stakeholders as well as the general public. We also identify the need to consider carefully the use of terminology and how this influences the understanding of the technology. Second, we elaborate on value sensitive design: the technology should be designed based upon the principles and values that emerge in the first step: societal dialogue. Third, research ethics deserves attention: for proceeding with first-in-human research with the technology, the process of recruiting and counseling eventual study participants and assuring their informed consent deserves careful attention. Fourth, ethical and legal research should concern the status of the subject in the AAPT. An eventual robust moral and legal framework for developing and implementing the technology in a research setting should combine all previous elements. With this roadmap, we emphasize the importance of stakeholder engagement throughout the process of developing and implementing the technology; this will contribute to ethically and responsibly innovating health care.

The use of a stronger instructional design by implementing repetitive practice in simulation-based obstetric team training: trainees’ satisfaction

Objective

This study compares satisfaction levels from multiprofessional obstetric care teams about simulation-based obstetric team training courses with and without the instructional design feature repetitive practice.

Methods

The present study is part of a multicentre cluster-randomised controlled trial (TOSTI trial) that investigated the effectiveness of a 1 day, multiprofessional, simulation-based obstetric team training. The initial training group received a training which was designed based on best practice. After 1 year, the control group received a training course in which the instructional design was changed by providing repetitive practice. All participants were asked to fill in a 29-item evaluation form with seven questions about baseline characteristics and 22 questions about training features. The questions about training features could be rated on a scale of 1 to 5. Finally, all participants were asked to rate the total training day on a scale of 1–10.

Results

The best practice group consisted of 471 trainees and the repetitive practice group of 549, including gynaecologists, residents, midwives and nurses. The best practice group rated the total training day significantly higher than the repetitive practice group (mean 8.8, SD 0.6 and mean 8.7, SD 0.6; p<0.003, Cohen’s d=0.19). Several training features were also scored higher in the best practice group.

Conclusion

This study showed that obstetric healthcare professionals rated a simulation-based obstetric team training course, with and without repetition of scenarios, both high. The training without the repetitive elements gained higher scores for the total training dayand several, and several training features were scored higher. The difference between the mean scores and the effect sizes for the training features were small. This implies that repetitive practice can be integrated in simulation-based team training to optimise learning effects, with small effects on trainees satisfaction.

The effect of intrauterine resuscitation by maternal hyperoxygenation on perinatal and maternal outcome: a randomized controlled trial

BACKGROUND

Maternal hyperoxygenation is widely used during labor as an intrauterine resuscitation technique. However, robust evidence regarding its beneficial effect and potential side effects is scarce, and previous studies show conflicting results.

OBJECTIVE

To assess the effect of maternal hyperoxygenation upon suspected fetal distress during the second stage of term labor on fetal heart rate, neonatal outcome, maternal side effects, and mode of delivery.

MATERIALS AND METHODS

In a single-center randomized controlled trial in a tertiary hospital in The Netherlands, participants were randomized in case of an intermediary or abnormal fetal heart rate pattern during the second stage of term labor, to receive either conventional care or 100% oxygen at 10 L/min until delivery. The primary outcome was the change in fetal heart rate pattern. Prespecified secondary outcomes were Apgar score, umbilical cord blood gas analysis, neonatal intensive care unit admission, perinatal death, free oxygen radical activity, maternal side effects, and mode of delivery. We performed subgroup analyses for intermediary and abnormal fetal heart rate, and for small for gestational age fetuses.

RESULTS

From March 2016 through April 2018, a total of 117 women were included. Fetal heart rate patterns could be analyzed in 71 women. Changes in fetal heart rate (defined as improvement, equal, or deterioration) in favor of maternal hyperoxygenation were significant (odds ratio, 5.7; 95% confidence interval, 1.7-19.1) using ordinal logistic regression. Apgar score, umbilical cord blood gas analysis, free oxygen radicals, and mode of delivery showed no significant differences between the intervention and control group. Among women with an abnormal fetal heart rate, there were fewer episiotomies on fetal indication in the intervention group (25%) than in the control group (65%, P < .01).

CONCLUSION

Maternal hyperoxygenation has a positive effect on the fetal heart rate in the presence of suspected fetal distress during the second stage of labor. There was no significant difference in the mode of delivery or neonatal outcome; however, significantly fewer episiotomies on fetal indication were performed following maternal hyperoxygenation in the subgroup with abnormal fetal heart rate pattern.

Comparison of the psychological and physiological effects on students of a video-assisted or text introduction to a simulated task

Introduction

The use of different methods for introducing the scenario in simulation-based medical education has not been investigated before and may be a useful element to optimise the effectiveness of learning. The aim of this study was to compare an immersive video-assisted introduction to a minimal text-based one, with regard to emotional assessment of the situation.

Methods

In this pilot study, 39 students participated in a medical simulated scenario. The students were randomly assigned to an experimental group (video-assisted introduction) or a control group (minimal textual introduction) and both were followed by performing surgery on LapSim (Surgical Science, Gothenburg, Sweden). The emotional assessment of the situation, cognitive appraisal, was defined as the ratio of the demands placed by an individual’s environment (primary appraisal) to that person’s resources to meet the demands (secondary appraisal). Secondary outcomes were anxiety (State-Trait Anxiety Inventory), physiological parameters (heart rate, heart rate variability, skin conductance, salivary cortisol), engagement (Game Engagement Questionnaire), motivation (Intrinsic Motivation Inventory) and performance (mean score in percentage calculated by LapSim of predefined levels).

Results

Participants in the immersive video group (n=17) were overloaded in terms of their perceived demands (a ratio of 1.17, IQR 0.30) compared with those in the control group (a ratio of 1.00, IQR 0.42, n=22) (P=0.01). No significant differences were found between the groups in secondary outcomes. Both groups showed an increase of anxiety after the introduction method. In the experimental group, this score increased from 9.0 to 11.0, and in the textual group from 7.5 to 10.5, both P<0.01.

Discussion

This study shows that the method of introducing a simulated scenario may influence the emotional assessment of the situation. It may be possible to make your simulation introduction too immersive or stimulating, which may interfere with learning. Further research will be necessary to investigate the impact and usefulness of these findings on learning in simulation-based medical education.

Clinical Use of Electrohysterography During Term Labor: A Systematic Review on Diagnostic Value, Advantages, and Limitations

Importance

Real-time electrohysterography (EHG)-based technologies have recently become available for uterine monitoring during term labor. Therefore, obstetricians need to be familiar with the diagnostic value, advantages, and limitations of using EHG.

Objective

The aims of this study were to determine the diagnostic value of EHG in comparison to (1) the intrauterine pressure catheter (IUPC), (2) the external tocodynamometer (TOCO), and (3) in case of maternal obesity; (4) to evaluate EHG from users' and patients' perspectives; and (5) to assess whether EHG can predict labor outcome.

Evidence Acquisition

A systematic review was performed in the MEDLINE, EMBASE, and Cochrane library in October 2017 resulting in 209 eligible records, of which 20 were included.

Results

A high sensitivity for contraction detection was achieved by EHG (range, 86.0%-98.0%), which was significantly better than TOCO (range, 46.0%-73.6%). Electrohysterography also enhanced external monitoring in case of maternal obesity. The contraction frequency detected by EHG was on average 0.3 to 0.9 per 10 minutes higher compared with IUPC, which resulted in a positive predictive value of 78.7% to 92.0%. When comparing EHG tocograms with IUPC traces, an underestimation of the amplitude existed despite that patient-specific EHG amplitudes have been mitigated by amplitude normalization. Obstetricians evaluated EHG tocograms as better interpretable and more adequate than TOCO. Finally, potential EHG parameters that could predict a vaginal delivery were a predominant fundal direction and a lower peak frequency.

Conclusions and Relevance

Electrohysterography enhances external uterine monitoring of both nonobese and obese women. Obstetricians consider EHG as better interpretable; however, they need to be aware of the higher contraction frequency detected by EHG and of the amplitude mismatch with intrauterine pressure measurements.

An empirical model for educational simulation of cervical dilation in first-stage labor

Background

Several models for educational simulation of labor and delivery were published in the literature and incorporated into a commercially available training simulator (CAE Healthcare Lucina). However, the engine of this simulator does not include a model for the clinically relevant indicators: uterine contraction amplitude and frequency, and cervical dilation. In this paper, such a model is presented for the primigravida in normal labor.

Methods

The conceptual and mathematical models represent oxytocin release by the hypothalamus, oxytocin pharmacokinetics, and oxytocin effect on uterine contractions, cervical dilation, and (positive) feedback from cervical dilation to oxytocin release by the hypothalamus.

Results

Simulation results for cervical dilation are presented, together with target data for a normal primigravida. Corresponding oxytocin concentrations and amplitude and frequency of uterine contractions are also presented.

Conclusion

An original empirical model for educational simulation of oxytocin concentration, uterine contractions, and cervical dilation in first-stage labor is presented. Simulation results for cervical dilation match target data for a normal patient. The model forms a basis for taking into account more independent variables and patient profiles and can thereby considerably expand the range of training scenarios that can be simulated.

Assessment tool for the instructional design of simulation-based team training courses: the ID-SIM

Introduction

To achieve an expert performance of care teams, adequate simulation-based team training courses with an effective instructional design are essential. As the importance of the instructional design becomes ever more clear, an objective assessment tool would be valuable for educators and researchers. Therefore, we aimed to develop an evidence-based and objective assessment tool for the evaluation of the instructional design of simulation-based team training courses.

Methods

A validation study in which we developed an assessment tool containing an evidence-based questionnaire with Visual Analogue Scale (VAS) and a visual chart directly translating the results of the questionnaire. Psychometric properties of the assessment tool were tested using five descriptions of simulation-based team training courses. An expert-opinion-based ranking from poor to excellent was obtained. Ten independent raters assessed the five training courses twice, by using the developed questionnaire with an interval of 2 weeks. Validity and reliability analyses were performed by using the scores from the raters and comparing them with the expert’s ranking. Usability was assessed by an 11-item survey.

Results

A 42-item questionnaire, using VAS, and a propeller chart were developed. The correlation between the expert-opinion-based ranking and the evaluators’ scores (Spearman correlation) was 0.95, and the variance due to subjectivity of raters was 3.5% (VTraining*Rater). The G-coefficient was 0.96. The inter-rater reliability (intraclass correlation coefficient (ICC)) was 0.91 (95% CI 0.77 to 0.99), and intra-rater reliability for the overall score (ICC) was ranging from 0.91 to 0.99.

Conclusions

We developed an evidence-based and reliable assessment tool for the evaluation of the instructional design of a simulation-based team training: the ID-SIM. The ID-SIM is available as a free mobile application.

Intrauterine resuscitation during the second stage of term labour by maternal hyperoxygenation versus conventional care: study protocol for a randomised controlled trial (INTEREST O2)

BACKGROUND

Perinatal asphyxia is, even in developed countries, one the major causes of neonatal morbidity and mortality. Therefore, if foetal distress during labour is suspected, one should try to restore foetal oxygen levels or aim for immediate delivery. However, studies on the effect of intrauterine resuscitation during labour are scarce. We designed a randomised controlled trial to investigate the effect of maternal hyperoxygenation on the foetal condition. In this study, maternal hyperoxygenation is induced for the treatment of foetal distress during the second stage of term labour.

METHODS/DESIGN

This study is a single-centre randomised controlled trial being performed in a tertiary hospital in The Netherlands. From among cases of a suboptimal or abnormal foetal heart rate pattern during the second stage of term labour, a total of 116 patients will be randomised to the control group, where normal care is provided, or to the intervention group, where before normal care 100% oxygen is supplied to the mother by a non-rebreathing mask until delivery. The primary outcome is change in foetal heart rate pattern. Secondary outcomes are Apgar score, mode of delivery, admission to the neonatal intensive care unit and maternal side effects. In addition, blood gas values and malondialdehyde are determined in umbilical cord blood.

DISCUSSION

This study will be the first randomised controlled trial to investigate the effect of maternal hyperoxygenation for foetal distress during labour. This intervention should be recommended only as a treatment for intrapartum foetal distress, when improvement of the foetal condition is likely and outweighs maternal and neonatal side effects.

TRIAL REGISTRATION

EudraCT, 2015-001654-15; registered on 3 April 2015. Dutch Trial Register, NTR5461; registered on 20 October 2015.

Simulation of fetal heart rate variability with a mathematical model

In the clinic, the cardiotocogram (CTG), the combined registration of fetal heart rate (FHR) and uterine contractions, is used to predict fetal well-being. Amongst others, fetal heart rate variability (FHRV) is an important indicator of fetal distress. In this study we add FHRV to our previously developed CTG simulation model, in order to improve its use as a research and educational tool. We implemented three sources of variability by applying either 1/f or white noise to the peripheral vascular resistance, baroreceptor output, or efferent vagal signal. Simulated FHR tracings were evaluated by visual inspection and spectral analysis. All power spectra showed a 1/f character, irrespective of noise type and source. The clinically observed peak near 0.1 Hz was only obtained by applying white noise to the different sources of variability. Similar power spectra were found when peripheral vascular resistance or baroreceptor output was used as source of variability. Sympathetic control predominantly influenced the low frequency power, while vagal control influenced both low and high frequency power. In contrast to clinical data, model results did not show an increase of FHRV during FHR decelerations. Still, addition of FHRV improves the applicability of the model as an educational and research tool.

A mathematical model to simulate the cardiotocogram during labor. Part B: Parameter estimation and simulation of variable decelerations

During labor and delivery the cardiotocogram (CTG), the combined registration of fetal heart rate (FHR) and uterine contractions, is used to monitor fetal well-being. In part A of our study we introduced a new mathematical computer model for CTG simulation in order to gain insight into the complex relation between these signals. By reducing model complexity and by using physically more realistic descriptions, this model was improved with respect to our previous model. Aim of part B of this study is to gain insight into the cascade of events from uterine contractions causing combined uterine flow reduction and umbilical cord compression, resulting in blood and oxygen pressure variations, which lead to changes in FHR via the baro- and chemoreflex. In addition, we extensively describe and discuss the estimation of model parameter values. Simulation results are in good agreement with sheep data and show the ability of the model to describe variable decelerations. Despite reduced model complexity, parameter estimation still remains difficult due to limited clinical data.

A mathematical model to simulate the cardiotocogram during labor. Part A: Model setup and simulation of late decelerations

The cardiotocogram (CTG) is commonly used to monitor fetal well-being during labor and delivery. It shows the input (uterine contractions) and output (fetal heart rate, FHR) of a complex chain of events including hemodynamics, oxygenation and regulation. Previously we developed a mathematical model to obtain better understanding of the relation between CTG signals and vital, but clinically unavailable signals such as fetal blood pressure and oxygenation. The aim of this study is to improve this model by reducing complexity of submodels where parameter estimation is complicated (e.g. regulation) or where less detailed model output is sufficient (e.g. cardiac function), and by using a more realistic physical basis for the description of other submodels (e.g. vessel compression). Evaluation of the new model is performed by simulating the effect of uterine contractions on FHR as initiated by reduction of uterine blood flow, mediated by changes in oxygen and blood pressure, and effected by the chemoreflex and baroreflex. Furthermore the ability of the model to simulate uterine artery occlusion experiments in sheep is investigated. With the new model a more realistic FHR decrease is obtained during contraction-induced reduction of uterine blood flow, while the reduced complexity and improved physical basis facilitate interpretation of model results and thereby make the model more suitable for use as a research and educational tool.

Insight into variable fetal heart rate decelerations from a mathematical model

During labor and delivery, variable decelerations in the fetal heart rate (FHR) are commonly seen on the cardiotocogram (CTG) that is used to monitor fetal welfare. These decelerations are often induced by umbilical cord compression from uterine contractions. Via changes in oxygenation and blood pressure, umbilical cord compression activates the chemo- and baroreceptor reflex, and thus affects FHR. Since the relation between the CTG and fetal oxygenation is complex, assessment of fetal welfare from the CTG is difficult. We investigated umbilical cord compression-induced variable decelerations with a mathematical model. For this purpose, we extended our model for decelerations originating from caput compression and reduced uterine blood flow with the possibility to induce umbilical venous, arterial and total cord occlusion. Model response during total occlusion is evaluated for varying contractions (duration and amplitude) and sensitivity of the umbilical resistance to the uterine pressure. A clinical scenario is used to simulate a labor CTG with variable decelerations. Simulation results show that fetal mean arterial pressure increases during umbilical cord occlusion, while fetal oxygenation drops. There is a clear relation between these signals and the resulting FHR. The extent of umbilical compression and thus FHR deceleration is positively related to increased contraction duration and amplitude, and increased sensitivity of the umbilical resistance to uterine pressure. No relation is found between contraction interval and FHR response, which can probably be ascribed to the lack of catecholamines in the model. The simulation model provides insight into the complex relation between uterine pressure, umbilical cord compression, fetal oxygenation, blood pressure and heart rate. The model can be used for individual learning, and incorporated in a simulation mannequin, be used to enhance obstetric team training.

Simulation of reflex late decelerations in labor with a mathematical model

Fetal welfare during labor and delivery is commonly monitored through the cardiotocogram (CTG), the combined registration of uterus contractions and fetal heart rate (FHR). From the CTG, the fetal oxygen state is estimated as the main indicator of the fetal condition, but this estimate is difficult to make, due to the complex relation between CTG and oxygen state. Mathematical models can be used to assist in the interpretation of the CTG, since they enable quantitative modeling of the flow of events through which uterine contractions affect fetal oxygenation and FHR. We propose a mathematical model to simulate reflex 'late decelerations', i.e. variations in FHR originating from uteroplacental flow reduction during uterine contractions and mediated by the baroreflex and the chemoreflex. Results for the uncompromised fetus show that partial oxygen pressures reduce in relation to the strength and duration of the contraction. Above a certain threshold, hypoxemia will evoke a late deceleration. Results for uteroplacental insufficiency, simulated by reduced uterine blood supply or reduced placental diffusion capacity, demonstrated lower baseline FHR and smaller decelerations during contraction. Reduced uteroplacental blood volume was found to lead to deeper decelerations only. The model response in several nerve blocking simulations was similar to experimental findings by Martin et al. [18], indicating a correct balance between vagal and sympathetic reflex pathways.