Publications by authors named "Johann Vargas-Calixto"

Article Synopsis
  • * Researchers analyzed data from around 41,000 term births, comparing 374 cases of HIE, 3,056 with fetal acidosis, and 37,546 healthy infants, using a random forest classifier for prediction.
  • * The system showed improved detection rates for HIE (61.8%) and fetal acidosis (48.3%) without increasing false positives in healthy infants, allowing for potential early clinical interventions.
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This article describes the methods used to build a large-scale database of more than 250,000 electronic fetal monitoring (EFM) records linked to a comprehensive set of clinical information about the infant, the mother, the pregnancy, labor, and outcome. The database can be used to investigate how birth outcome is related to clinical and EFM features. The main steps involved in building the database were: (1) Acquiring the raw EFM recording and clinical records for each birth.

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Article Synopsis
  • This study focuses on improving the detection of fetuses at risk for fetal acidosis or hypoxic-ischemic encephalopathy (HIE) during labor by analyzing fetal heart rate (FHR) and uterine pressure (UP) signals.
  • A random forest classifier was developed to give intervention recommendations based on feature data from FHR and UP collected in 20-minute intervals, showing a significant increase in identifying at-risk babies well before delivery.
  • The system identified more cases of HIE and acidosis, suggesting early intervention opportunities that could lower HIE rates, despite a slight rise in cesarean section rates among healthy births.
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Nulliparous pregnancies, those where the mother has not previously given birth, are associated with longer labors and hence expose the fetus to more contractions and other adverse intrapartum conditions such as chorioamnionitis. The objective of the present study was to test if accounting for nulliparity could improve the detection of fetuses at increased risk of developing hypoxic-ischemic encephalopathy (HIE). During labor, clinicians assess the fetal heart rate and uterine pressure signals to identify fetuses at risk of developing HIE.

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Visual assessment of the evolution of fetal heart rate (FHR) and uterine pressure (UP) patterns is the standard of care in the intrapartum period. Unfortunately, this assessment has high levels of intra- and inter-observer variability. This study processed and analyzed FHR and UP patterns using computerized pattern recognition tools.

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The research objective of our group is to improve the intrapartum detection of cardiotocography tracings associated with an increased risk of developing fetal acidosis and subsequent hypoxic-ischemic encephalopathy (HIE). The detection methods that we aim to develop must be sensitive to abnormal tracings without causing excessive unnecessary interventions. Past studies showed that the dynamic response of fetal heart rate (FHR) to uterine pressure (UP) during the intrapartum could be modelled using linear systems.

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Continuous electronic fetal monitoring and the access to databases of fetal heart rate (FHR) data have sparked the application of machine learning classifiers to identify fetal pathologies. However, most fetal heart rate data are acquired using Doppler ultrasound (DUS). DUS signals use autocorrelation (AC) to estimate the average heartbeat period within a window.

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Our research goal is to improve the intrapartum identification of tracings associated with severe acidosis at birth and subsequent hypoxic-ischemic encephalopathy so that timely interventions could avoid such complications without causing excessive unnecessary interventions in births with normal outcomes. The present study examines the evolution of fetal heart rate (FHR) features over the course of labor. We analyzed FHR signals collected in the last 6 hours before delivery in 21,853 births with normal neonatal outcomes and in 163 that developed hypoxic-ischemic encephalopathy (HIE) from 15 hospitals of Kaiser Permanente Northern California.

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