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J Bernardes

Publications and source records attributed to J Bernardes.

At least 19 recordsLinked to original sources
PubMed2000

An interactive web site for research on fetal heart rate monitoring.

BACKGROUND: Traditional methods of exchange of research information may not be rapid enough, especially for international multicenter studies or when discussing controversial issues such as the value of fetal monitoring. The Internet is a useful tool that provides numerous opportunities for immediate communication within a large and diverse community of researchers. METHOD: A Web site at http://www.sisporto.med.up.pt was developed for a multicenter research project with interlinked pages on automated fetal heart rate (FHR) monitoring. It includes background knowledge about the subject, detailed information about the project, and a few interactive pages. These pages allow online discussions, simulations of data analysis, and download of data for local FHR analysis. EXPERIENCE: The Web site has been accessed from all over the world. In particular, participating research centers have had easy and fast access to background project information, and a few other clinicians and researchers participated in our online discussions and used the simulation tools or the data provided for analysis of typical FHR patterns. CONCLUSION: Web sites can be useful in multicenter research projects and for scientific information exchange.

Female↗
PubMed2000

Fetal heart rate baselines in twins. Interobserver agreement in antepartum estimation.

OBJECTIVE: To assess interobserver agreement in antepartum estimation of fetal heart rate (FHR) baselines in twins. STUDY DESIGN: Two residents and one specialist in obstetrics and gynecology, all with special interest in FHR monitoring, independently estimated baselines in 162 consecutive antepartum FHR tracings recorded in 24 twins. Tracings were obtained with a dual-channel fetal monitor for the simultaneous recording of both twins' heart rates. Baselines were estimated, as single values corresponding to the mean of the lowest stable FHR segment, in the absence of fetal movements and uterine contractions, within physiologic limits (110-150 beats per minute [bpm]). If these criteria were not met, the possibility of persistent bradycardia or tachycardia was considered, and if this was confirmed in a tracing with at least 40 minutes, a baseline < 110 or > 150 bpm was chosen. Interobserver agreement was assessed by the proportions of agreement (PA), kappa statistic (K) and intraclass correlation coefficient (ICCC), with 95% confidence intervals (CIs). RESULTS: Interobserver agreement was excellent, with a PA of 0.90 (95% CI: 0.89-0.91), K of 0.88 (95% CI: 0.84-0.92) and ICCC of 0.91 (95% CI: 0.88-0.94). CONCLUSION: Interobserver agreement in antepartum estimation of fetal heart rate baselines in twins was excellent with the baseline concept used in this study.

Adult↗
PubMed1999

Inconsistencies in classification by experts of cardiotocograms and subsequent clinical decision.

Inter-observer agreement in the interpretation according to the FIGO guidelines of 33 cardiotocographic tracings by experts and subsequent clinical decision was evaluated, using the kappa statistic (K) and the proportions of agreement (Pa). Overall agreement in the classification of tracings was fair (K = 0.48) and was better for normal (Pa = 0.62), than for suspicious (Pa = 0.42) or pathologic tracings (Pa = 0.25). Overall agreement on clinical decision was slightly higher (K = 0.59), but mostly was centred on the decision to take 'no action' (Pa = 0.79). Experts especially disagreed over the decisions to 'monitor closely' (Pa = 0.14) or to 'intervene immediately' (Pa = 0.38). These limitations should be taken into account in clinical audits and in medical jurisprudence.

Cardiotocography↗
PubMed1998

Classification of foetal heart rate sequences based on fractal features.

Visual inspection of foetal heart rate (FHR) sequences is an important means of foetal well-being evaluation. The application of fractal features for classifying physiologically relevant FHR sequence patterns is reported. The use of fractal features is motivated by the difficulties exhibited by traditional classification schemes to discriminate some classes of FHR sequence and by the recognition that this type of signal exhibits features on different scales of observation, just as fractal signals do. To characterise the signals by fractal features, two approaches are taken. The first modes the FHR sequences as temporal fractals. The second uses techniques from the chaos-theory field and aims to model the attractor based on FHR sequences. The fractal features determined by both approaches are used to design a Bayesian classification scheme. Classification results for three classes are presented; they are quite satisfactory and illustrate the importance of this type of methodology.

Bayes Theorem↗
PubMed1998

Objective computerized fetal heart rate analysis.

OBJECTIVE: To assess the validity of a computerized methodology for cardiotocogram analysis based on a recently described reproducible visual estimation of the baseline. METHODS: Forty-two antepartum and 43 intrapartum cardiotocograms (CTGs) acquired by a personal computer were selected. Antepartum tracings were performed in the 48 h that preceded an elective cesarean section, and intrapartum tracings were performed until delivery. FHR baselines were estimated by an expert, according to an objective and reproducible methodology. Using these baselines, automated detection of accelerations and decelerations and estimation of variability was performed by the personal computer. A quantitative adaptation of the FIGO guidelines for fetal monitoring was used to classify tracings. Perinatal outcome was classified according to the Apgar score and umbilical arterial pH. Validity was then assessed by the proportions of agreement (PA), kappa statistic (K), sensitivity and specificity, with 95% confidence intervals (95% CI). Cases showing a disagreement between CTG and perinatal classification were reviewed and an adjustment in baseline definition was tested. RESULTS: The initial overall PA and kappa between CTG and perinatal classification were, respectively, 0.79 (95% CI: 0.69-0.87) and 0.62 (95% CI: 0.41-0.83). The overall PA and K, after baseline adjustment were, respectively, 0.89 (95% CI: 0.81-0.95) and 0.78 (95% CI: 0.58-0.98). Sensitivities and specificities ranged between 79% (95% CI: 60-92%) and 100% (95% CI: 95-100%). CONCLUSIONS: Good clinical prediction may be possible with an objective methodology for cardiotocogram analysis based on a recently described reproducible baseline estimation.

Cardiotocography↗
PubMed1998

Semiautomated ultrasonographic measurement of fetal nuchal translucency using a computer software tool.

Nuchal translucency (NT) thickness measurement has been recently proposed as a part of routine ultrasound scanning during the late first trimester of pregnancy, for the early screening of chromosomal abnormalities. Manual determination of NT is currently performed using electronic calipers placed by the operator in the middle of two echogenic lines displayed on the screen. Therefore, intraobserver and interobserver repeatability can be questioned. This paper presents a software tool that has been developed for achieving this goal in a semiautomatic way, improving the reproducibility of the method.

Chromosome Aberrations↗
PubMed1997

Evaluation of interobserver agreement of cardiotocograms.

OBJECTIVE: To evaluate interobserver agreement in visual analysis of each cardiotocographic event. METHODS: Three experts independently divided 16 antepartum and 17 intrapartum cardiotocograms into baseline segments, accelerations and decelerations, according to the FIGO guidelines. Baseline segments were further classified as having normal, reduced or increased variability and decelerations as early, late and variable. Uterine activity was divided into tonus and contractions. Agreement was assessed by the proportions of agreement (pa) with 95% confidence intervals. RESULTS: Reproducibility in assessment of baseline segments with normal variability, accelerations and uterine activity was acceptable (pa = 0.56-0.71) whereas that of other segments was not (pa = 0.14-0.45). CONCLUSIONS: Analysis of most cardiotocographic events is poorly reproducible, even when experts use the FIGO guidelines. This may be explained by some still ambiguous guidelines, by eyeball limitations in evaluation of subtle events, and by the incapacity of busy clinicians to assess complex and multiple cardiotocographic events in a systematic and disciplined fashion.

Cardiotocography↗