Baillière's Clinical Obstetrics and Gynaecology, 1990
Summary Important biological signals from the fetus, including fetal heart rate and fetal movemen... more Summary Important biological signals from the fetus, including fetal heart rate and fetal movement, were obtained electronically by recent medical engineering techniques and processed (usually) via analogue-to-digital converter followed by analysis on a personal computer. The knowledge of obstetrical experts was analysed and used in computer processing. Fetal heart rate changes were initially studied by the use of a minicomputer, programmed to provide automatic quantification of the signal and diagnosis of fetal distress. The program was memorized by programmable read only memory (PROM) and used in a clinical system. The results obtained by the system were used in many obstetrical research studies, and automatic diagnosis was used in clinical practice. An ultrasonic Doppler fetal actocardiograph was also created. The amplitude and interval of the electrical deflections produced by fetal movement were analysed. Fetal behavioural states were automatically recognized in this way. Cross-correlational analysis of fetal heart rate and fetal movement showed a close relationship between the two phenomena.
The aim of this study was to analyze maternal and child health indicators and infant mortality ra... more The aim of this study was to analyze maternal and child health indicators and infant mortality rate (IMR) at the cities located at the 18th Health Division (HD) in Parana State, Brazil. In this ecological study we analyzed all live births and infant deaths which occurred from 2000 to 2009 at the 18th HD, collecting data from the Mortality Information Database and the Live Births Information Database. The variables assessed were grouped into maternal, pregnancy and delivery, and neonatal variables. The analysis was conducted using the mean percentage of each variable and the IMR calculated for both periods: from 2000 to 2004 and from 2005 to 2009. The IMR was reduced considerably, following Brazil's and Paraná State's trend. Maternal indicators went down regarding the mean percentage of teenage mothers and low education, whereas they went up regarding mother with 35 years old or older and mothers without a partner. Pregnancy indicators showed increased prematurity and cesarea...
The journal of maternal-fetal & neonatal medicine : the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians, Jan 3, 2016
SisPorto 4.0 is the most recent version of a program for computer analysis of cardiotocographic s... more SisPorto 4.0 is the most recent version of a program for computer analysis of cardiotocographic signals and ST events, which has been adapted to the 2015 International Federation of Gynecology and Obstetrics (FIGO) guidelines for intrapartum fetal monitoring. This paper provides a detailed description of the analysis performed by the system, including the signal processing algorithms involved in identification of basic CTG features and the resulting real-time alerts.
European Journal of Obstetrics & Gynecology and Reproductive Biology, 2016
To establish reference values for cardiotocographic (CTG) parameters from 24 to 41 weeks of gesta... more To establish reference values for cardiotocographic (CTG) parameters from 24 to 41 weeks of gestation in normal pregnancies. Retrospective cross-sectional study, using the first antepartum tracing of singleton fetuses with normal pregnancy outcomes (term birth, normal birthweight, normal umbilical artery pH and Apgar scores, no intensive care unit admission). Cases were consecutively selected from a hospital electronic patient record, and analyzed using the OmniviewSisPorto 3.7 system. Variables were compared between male and female fetuses, by gestational age, and percentile curves were constructed. A total of 9701 tracings (corresponding to 9701 fetuses) were analyzed. All CTG parameters changed significantly throughout gestation in both genders, with a decrease in baseline and decelerations, and an increase in average long-term variability (LTV), average short-term variability (STV), accelerations and uterine contractions. The mean baseline value decreased 9bpm, and its range almost doubled from 24 to 40 weeks. Until 30 weeks the lower percentiles for average LTV were below 5bpm, and the minimum value for average STV was never below 1bpm. The proportion of tracings without accelerations decreased from 30.1% at 24-25 weeks to 0.5% at 39 weeks. The median number of decelerations was practically zero for all gestational ages. All CTG variables, except decelerations and uterine contractions, showed statistically significant gender differences: baseline was consistently higher in females, while average LTV and average STV tended to be lower in females throughout most of pregnancy. Separate percentile curves were constructed for male and female fetuses. This study provides reference values for CTG parameters throughout pregnancy, derived from the largest dataset of healthy fetuses published to date. For the first time, gender differences were clearly demonstrated in fetal life, and percentile curves constructed separately for male and female fetuses.
Medical & biological engineering & computing, Jan 29, 2015
Fetal heart rate (FHR) monitoring is used routinely in labor, but conventional methods have a lim... more Fetal heart rate (FHR) monitoring is used routinely in labor, but conventional methods have a limited capacity to detect fetal hypoxia/acidosis. An exploratory study was performed on the simultaneous assessment of maternal heart rate (MHR) and FHR variability, to evaluate their evolution during labor and their capacity to detect newborn acidemia. MHR and FHR were simultaneously recorded in 51 singleton term pregnancies during the last two hours of labor and compared with newborn umbilical artery blood (UAB) pH. Linear/nonlinear indices were computed separately for MHR and FHR. Interaction between MHR and FHR was quantified through the same indices on FHR-MHR and through their correlation and cross-entropy. Univariate and bivariate statistical analysis included nonparametric confidence intervals and statistical tests, receiver operating characteristic curves and linear discriminant analysis. Progression of labor was associated with a significant increase in most MHR and FHR linear in...
Fetal heart rate monitoring is widespread all over the world. However, despite recent advances in... more Fetal heart rate monitoring is widespread all over the world. However, despite recent advances in analysis methods, there are still inherent technical limitations. One of the main challenges is to extract accurate and useful information from the external fetal ECG, which may provide a better non-invasive characterization of the fetal cardiovascular system during the third trimester of pregnancy. In this work, maternal ECG waves were first located using a wavelet transform based system previously developed and validated. Then, a similar strategy with adapted parameters for fetal physiology was applied to detect fetal QRS, excluding signal singularities associated to maternal heartbeats. Single lead based annotations were combined in a single annotator from which RR and HRV fetal measures could be taken. Data provided from PhysioNet 2013 Challenge was considered. The average scores were: 521.43 / 401,50 for event 4 and 32.99 / 29,70 for event 5 on set B /A respectively. The median rat...
2014 8th Conference of the European Study Group on Cardiovascular Oscillations (ESGCO), 2014
ABSTRACT Cardiotocography (CTG) is the most frequently used electronic fetal monitoring technique... more ABSTRACT Cardiotocography (CTG) is the most frequently used electronic fetal monitoring technique, both in the antepartum and intrapartum periods. A few systems for computer analysis of CTG tracings have been developed, but there is still a large room for improvement in their capacity to diagnose fetal hypoxia/acidosis. Research on fetal heart rate (FHR) analysis has shown that several factors are not commonly considered in such systems, and these can significantly influence the computation of FHR indices: among them are gender, gestational age and fetal behavioral states. A short review is provided on the influence of these factors in FHR analysis, particularly in linear (time- and frequency-domain) and nonlinear (entropy) indices. In conclusion, the effect of gender, gestational age and behavioral states on FHR analysis may need to be considered for the improvement of computer systems developed for that purpose.
Approximate entropy (ApEn) has been used by several researchers as a means to characterize the ir... more Approximate entropy (ApEn) has been used by several researchers as a means to characterize the irregularity of fetal heart rate (FHR), a major contributor to fetal risk assessment. The present work starts by analyzing the influence of accelerative and decelerative (AD) components of the FHR signal in the computation of ApEn. Having shown that the AD components may completely distort the ApEn evaluation we proceed to present two methods of eliminating the influence of the AD components: wavelet filtering; AD detection using specific algorithms based on well-established physiological criteria. We obtained good results with the first method when applied to simulated signals; however it proved unreliable in the practical application of discriminating normal from pathological fetal FHR. With the second method we were able to achieve this discrimination with high statistical significance.
Objective: To compare fetal heart rate (FHR) signals acquired simultaneously by an external ultra... more Objective: To compare fetal heart rate (FHR) signals acquired simultaneously by an external ultrasound probe and a scalp electrode during the second stage of labor. Methods: This was a prospective observational study in a labor ward of a tertiary care university hospital. The population was women in labor with uneventful singleton pregnancies at term. Simultaneous external and internal FHR monitoring was performed in 67 consecutively recruited women during the second stage of labor. Cases were subsequently excluded if the trace length was under 40 min, cesarean birth occurred, or the interval between trace-end and birth exceeded 5 min, leaving a total of 33 traces for analysis. The last 40–60 min of these traces were analyzed by a computer system (Omniview-SisPorto® 3.5; Speculum®, Lisbon, Portugal) to quantify cardiotocographic parameters. Paired sample t-test and Bland-Altman limits of agreement (LoA) were used for statistical analysis, setting significance at 0.05. The main outco...
A variety of systems for centralised viewing of fetal signals during labour are currently availab... more A variety of systems for centralised viewing of fetal signals during labour are currently available, allowing simultaneous monitoring of multiple tracings in one or more locations. Display of maternal vital signs, ST signals and an electronic partogram are available in the majority of these systems. A few of them have incorporated computer analysis of cardiotocographic signals or combined cardiotocographic and ST data analysis. Computer analysis may elicit real-time alerts for healthcare professionals when changes associated with fetal hypoxia are detected. Central fetal monitoring systems have been installed in a large number of maternity hospitals in industrialised countries, but there is still limited evidence of their impact on perinatal indicators, on the behaviour of healthcare professionals and on related health costs.
Digital storage of cardiotocographic (CTG) tracings by fetal central monitoring systems (fCMS) ob... more Digital storage of cardiotocographic (CTG) tracings by fetal central monitoring systems (fCMS) obviates the need for printing, or alternatively, the tracings can be printed in regular paper instead of CTG thermal paper. We aimed at evaluating the impact of the introduction of the Omniview-SisPorto(®) system on CTG paper costs in a large university hospital. After introduction of the fCMS, there was an 87% reduction in median annual expenses with CTG paper in the labour ward (p = 0.011) and a 78% decrease in the prenatal clinic (p = 0.017), despite a more than 40% increase in the median number of observed women. Routine use of fCMS may provide an important reduction in hospital expenses associated with the use of thermal CTG paper, thus reducing the investment made in their acquisition and maintenance.
Baillière's Clinical Obstetrics and Gynaecology, 1990
Summary Important biological signals from the fetus, including fetal heart rate and fetal movemen... more Summary Important biological signals from the fetus, including fetal heart rate and fetal movement, were obtained electronically by recent medical engineering techniques and processed (usually) via analogue-to-digital converter followed by analysis on a personal computer. The knowledge of obstetrical experts was analysed and used in computer processing. Fetal heart rate changes were initially studied by the use of a minicomputer, programmed to provide automatic quantification of the signal and diagnosis of fetal distress. The program was memorized by programmable read only memory (PROM) and used in a clinical system. The results obtained by the system were used in many obstetrical research studies, and automatic diagnosis was used in clinical practice. An ultrasonic Doppler fetal actocardiograph was also created. The amplitude and interval of the electrical deflections produced by fetal movement were analysed. Fetal behavioural states were automatically recognized in this way. Cross-correlational analysis of fetal heart rate and fetal movement showed a close relationship between the two phenomena.
The aim of this study was to analyze maternal and child health indicators and infant mortality ra... more The aim of this study was to analyze maternal and child health indicators and infant mortality rate (IMR) at the cities located at the 18th Health Division (HD) in Parana State, Brazil. In this ecological study we analyzed all live births and infant deaths which occurred from 2000 to 2009 at the 18th HD, collecting data from the Mortality Information Database and the Live Births Information Database. The variables assessed were grouped into maternal, pregnancy and delivery, and neonatal variables. The analysis was conducted using the mean percentage of each variable and the IMR calculated for both periods: from 2000 to 2004 and from 2005 to 2009. The IMR was reduced considerably, following Brazil's and Paraná State's trend. Maternal indicators went down regarding the mean percentage of teenage mothers and low education, whereas they went up regarding mother with 35 years old or older and mothers without a partner. Pregnancy indicators showed increased prematurity and cesarea...
The journal of maternal-fetal & neonatal medicine : the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians, Jan 3, 2016
SisPorto 4.0 is the most recent version of a program for computer analysis of cardiotocographic s... more SisPorto 4.0 is the most recent version of a program for computer analysis of cardiotocographic signals and ST events, which has been adapted to the 2015 International Federation of Gynecology and Obstetrics (FIGO) guidelines for intrapartum fetal monitoring. This paper provides a detailed description of the analysis performed by the system, including the signal processing algorithms involved in identification of basic CTG features and the resulting real-time alerts.
European Journal of Obstetrics & Gynecology and Reproductive Biology, 2016
To establish reference values for cardiotocographic (CTG) parameters from 24 to 41 weeks of gesta... more To establish reference values for cardiotocographic (CTG) parameters from 24 to 41 weeks of gestation in normal pregnancies. Retrospective cross-sectional study, using the first antepartum tracing of singleton fetuses with normal pregnancy outcomes (term birth, normal birthweight, normal umbilical artery pH and Apgar scores, no intensive care unit admission). Cases were consecutively selected from a hospital electronic patient record, and analyzed using the OmniviewSisPorto 3.7 system. Variables were compared between male and female fetuses, by gestational age, and percentile curves were constructed. A total of 9701 tracings (corresponding to 9701 fetuses) were analyzed. All CTG parameters changed significantly throughout gestation in both genders, with a decrease in baseline and decelerations, and an increase in average long-term variability (LTV), average short-term variability (STV), accelerations and uterine contractions. The mean baseline value decreased 9bpm, and its range almost doubled from 24 to 40 weeks. Until 30 weeks the lower percentiles for average LTV were below 5bpm, and the minimum value for average STV was never below 1bpm. The proportion of tracings without accelerations decreased from 30.1% at 24-25 weeks to 0.5% at 39 weeks. The median number of decelerations was practically zero for all gestational ages. All CTG variables, except decelerations and uterine contractions, showed statistically significant gender differences: baseline was consistently higher in females, while average LTV and average STV tended to be lower in females throughout most of pregnancy. Separate percentile curves were constructed for male and female fetuses. This study provides reference values for CTG parameters throughout pregnancy, derived from the largest dataset of healthy fetuses published to date. For the first time, gender differences were clearly demonstrated in fetal life, and percentile curves constructed separately for male and female fetuses.
Medical & biological engineering & computing, Jan 29, 2015
Fetal heart rate (FHR) monitoring is used routinely in labor, but conventional methods have a lim... more Fetal heart rate (FHR) monitoring is used routinely in labor, but conventional methods have a limited capacity to detect fetal hypoxia/acidosis. An exploratory study was performed on the simultaneous assessment of maternal heart rate (MHR) and FHR variability, to evaluate their evolution during labor and their capacity to detect newborn acidemia. MHR and FHR were simultaneously recorded in 51 singleton term pregnancies during the last two hours of labor and compared with newborn umbilical artery blood (UAB) pH. Linear/nonlinear indices were computed separately for MHR and FHR. Interaction between MHR and FHR was quantified through the same indices on FHR-MHR and through their correlation and cross-entropy. Univariate and bivariate statistical analysis included nonparametric confidence intervals and statistical tests, receiver operating characteristic curves and linear discriminant analysis. Progression of labor was associated with a significant increase in most MHR and FHR linear in...
Fetal heart rate monitoring is widespread all over the world. However, despite recent advances in... more Fetal heart rate monitoring is widespread all over the world. However, despite recent advances in analysis methods, there are still inherent technical limitations. One of the main challenges is to extract accurate and useful information from the external fetal ECG, which may provide a better non-invasive characterization of the fetal cardiovascular system during the third trimester of pregnancy. In this work, maternal ECG waves were first located using a wavelet transform based system previously developed and validated. Then, a similar strategy with adapted parameters for fetal physiology was applied to detect fetal QRS, excluding signal singularities associated to maternal heartbeats. Single lead based annotations were combined in a single annotator from which RR and HRV fetal measures could be taken. Data provided from PhysioNet 2013 Challenge was considered. The average scores were: 521.43 / 401,50 for event 4 and 32.99 / 29,70 for event 5 on set B /A respectively. The median rat...
2014 8th Conference of the European Study Group on Cardiovascular Oscillations (ESGCO), 2014
ABSTRACT Cardiotocography (CTG) is the most frequently used electronic fetal monitoring technique... more ABSTRACT Cardiotocography (CTG) is the most frequently used electronic fetal monitoring technique, both in the antepartum and intrapartum periods. A few systems for computer analysis of CTG tracings have been developed, but there is still a large room for improvement in their capacity to diagnose fetal hypoxia/acidosis. Research on fetal heart rate (FHR) analysis has shown that several factors are not commonly considered in such systems, and these can significantly influence the computation of FHR indices: among them are gender, gestational age and fetal behavioral states. A short review is provided on the influence of these factors in FHR analysis, particularly in linear (time- and frequency-domain) and nonlinear (entropy) indices. In conclusion, the effect of gender, gestational age and behavioral states on FHR analysis may need to be considered for the improvement of computer systems developed for that purpose.
Approximate entropy (ApEn) has been used by several researchers as a means to characterize the ir... more Approximate entropy (ApEn) has been used by several researchers as a means to characterize the irregularity of fetal heart rate (FHR), a major contributor to fetal risk assessment. The present work starts by analyzing the influence of accelerative and decelerative (AD) components of the FHR signal in the computation of ApEn. Having shown that the AD components may completely distort the ApEn evaluation we proceed to present two methods of eliminating the influence of the AD components: wavelet filtering; AD detection using specific algorithms based on well-established physiological criteria. We obtained good results with the first method when applied to simulated signals; however it proved unreliable in the practical application of discriminating normal from pathological fetal FHR. With the second method we were able to achieve this discrimination with high statistical significance.
Objective: To compare fetal heart rate (FHR) signals acquired simultaneously by an external ultra... more Objective: To compare fetal heart rate (FHR) signals acquired simultaneously by an external ultrasound probe and a scalp electrode during the second stage of labor. Methods: This was a prospective observational study in a labor ward of a tertiary care university hospital. The population was women in labor with uneventful singleton pregnancies at term. Simultaneous external and internal FHR monitoring was performed in 67 consecutively recruited women during the second stage of labor. Cases were subsequently excluded if the trace length was under 40 min, cesarean birth occurred, or the interval between trace-end and birth exceeded 5 min, leaving a total of 33 traces for analysis. The last 40–60 min of these traces were analyzed by a computer system (Omniview-SisPorto® 3.5; Speculum®, Lisbon, Portugal) to quantify cardiotocographic parameters. Paired sample t-test and Bland-Altman limits of agreement (LoA) were used for statistical analysis, setting significance at 0.05. The main outco...
A variety of systems for centralised viewing of fetal signals during labour are currently availab... more A variety of systems for centralised viewing of fetal signals during labour are currently available, allowing simultaneous monitoring of multiple tracings in one or more locations. Display of maternal vital signs, ST signals and an electronic partogram are available in the majority of these systems. A few of them have incorporated computer analysis of cardiotocographic signals or combined cardiotocographic and ST data analysis. Computer analysis may elicit real-time alerts for healthcare professionals when changes associated with fetal hypoxia are detected. Central fetal monitoring systems have been installed in a large number of maternity hospitals in industrialised countries, but there is still limited evidence of their impact on perinatal indicators, on the behaviour of healthcare professionals and on related health costs.
Digital storage of cardiotocographic (CTG) tracings by fetal central monitoring systems (fCMS) ob... more Digital storage of cardiotocographic (CTG) tracings by fetal central monitoring systems (fCMS) obviates the need for printing, or alternatively, the tracings can be printed in regular paper instead of CTG thermal paper. We aimed at evaluating the impact of the introduction of the Omniview-SisPorto(®) system on CTG paper costs in a large university hospital. After introduction of the fCMS, there was an 87% reduction in median annual expenses with CTG paper in the labour ward (p = 0.011) and a 78% decrease in the prenatal clinic (p = 0.017), despite a more than 40% increase in the median number of observed women. Routine use of fCMS may provide an important reduction in hospital expenses associated with the use of thermal CTG paper, thus reducing the investment made in their acquisition and maintenance.
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