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Biomedical subjects

J Bernardes

Publications and source records attributed to J Bernardes.

34 records · Page 2Linked to original sources
PubMed1997

Antepartum fetal cerebral hemorrhage not predicted by current surveillance methods in cholestasis of pregnancy.

BACKGROUND: The reason for increased fetal mortality in cholestasis of pregnancy is not completely understood. Intracerebral hemorrhage due to coagulation disorders, similar to those reported in the mother, is a possible explanation. CASE: Antepartum fetal death occurred at 37 weeks in a primigravida with cholestasis of pregnancy. The woman was taking no medication. Autopsy revealed extensive cerebral hemorrhage. A cardiotocogram and biophysical profile performed 24 hours and 5 days, respectively, before fetal death had been normal. CONCLUSION: Antepartum fetal death may occur in patients with mild cholestasis who are taking no medication. Intracerebral hemorrhage is a possible cause, and this may be unpredictable with current methods of fetal surveillance. This possibility constitutes an argument in support of delivering these pregnancies as soon as lung maturity is achieved.

Adult↗
PubMed1992

[Automated analysis of cardiotocographic signals].

Cardiotocographic signals, used as a perinatal diagnostic tool, comprise fetal heart beat signals (FHR), uterine contractions (UC) and fetal movements (FM). Visual inspection of these three signals is limited, subjective, time consuming and with low reproducibility. The present paper illustrates an application of signal processing techniques to the automatic analysis of cardiotocographic signals, allowing to overcome visual inspection limitations. Porto system of cardiotocograms automatic analysis acquires the signals from a conventional cardiotocograph. The signals are stored and processed by a personal computer. System software allows the user to perform several operations such as signal acquisition, signal storage and retrieval from files, signal analysis and display. Signal analysis is preceded by various signal conditioning operations (filtering, spike removal, etc.) and consists in the estimation of several parameters with diagnostic value: FHR baseline; FHR accelerations and decelerations; uterine contractions; long and short term FHR variability. The system prototype is working on a routine basis at the Obstetrics Department of S. João Hospital (main Oporto Hospital) and is being evaluated using a large data set. A preliminary evaluation performed by 3 experts on a 50 cases set, yielded an agreement rate with computer measurements of 98% for the baseline, 72% to 82% for accelerations and decelerations and 76% for the uterine contractions.

Cardiotocography↗
PubMed1991

The Porto system for automated cardiotocographic signal analysis.

Cardiotocography (CTG) lacks reliability and reproducibility and these problems are believed to be overcome by computer analysis. In this article we describe a system developed for routine clinical automated CTG analysis based on a low cost personal computer. Presently the system has processed 70 ten minute tracings. Fetal heart rate baseline, acceleration--deceleration detection, and long term variability estimation were performed in a satisfactory way.

Cardiotocography↗
PubMedDate not supplied

SisPorto 2.0: a program for automated analysis of cardiotocograms.

OBJECTIVE: To describe the latest version of SisPorto, a program for automated analysis of cardiotocograms that closely follows the FIGO guidelines, analyses ante- and intrapartum tracings, performs no signal reduction, and has the possibility of simultaneously recording twins. METHODS: A detailed description of the program's processing algorithms and operation is provided, as well as the main results of the studies performed to-date with this system. RESULTS: Considering both current and previous versions of the program, SisPorto has been tested in over 6000 pregnancies. The system's FHR baseline was compared with an average of three experts' estimates, and the difference was under 8 bpm in all cases. A fair to good agreement was found with experts' identification of accelerations, decelerations, contractions, and normal/reduced variability (proportions of agreement 0.64-0.89). In a preliminary validity study (n = 85), a sensitivity of 100% and a specificity of 99% were obtained in prediction of poor neonatal outcome. The system is currently undergoing an international multicentre validation study. CONCLUSIONS: Although still at the research level, a considerable experience has now been gathered with this system. Promising results have been achieved in studies comparing SisPorto with experts' analysis and in those evaluating the validity of the system.

Algorithms↗