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At least 109 records · Page 6Linked to original sources
PubMed2004

Cardiotocography and medicolegal issues.

Obstetric litigation is on the increase. A review of litigation cases reveals that the majority of claims relating to the intrapartum period arise because the cardiotocograph- (CTG) was misinterpreted or because inappropriate action was taken in the presence of fetal heart rate abnormalities. Compulsory education and training in the interpretation of CTGs and in best practice are key factors in minimizing the threat of litigation. Newer methods, such as pulse oximetry or fetal electrocardiogram waveform analysis, can act as adjuncts to CTG and help to avoid birth asphyxia and hence litigation.

Asphyxia Neonatorum↗
PubMed1997

Chaos theory and power spectrum analysis in computerized cardiotocography.

Power spectrum and chaos theory analysis, methods recently applied to fetal surveillance, may offer an effective tool for recognising fetal hypoxia and consequential collapse of fetal homeostasis earlier than at present. However, strict continuity and high precision of input data is an indispensable prerequisite. If one overlooks this requirement the results may be misleading. The aim of the present work was to find a method that provides strictly continuous and highly precise beat-to-beat FHR data values. It was found that only the determination of heart beat intervals between successive R peaks, using the digital FECG recording technique developed here, meets the necessary requirements for power spectrum and chaos theory analysis.

Cardiotocography↗
PubMed1997

The efficacy of intrapartum fetal surveillance when fetal pulse oximetry is added to cardiotocography.

OBJECTIVE: To determine if oxygen saturation measurement with pulse oximetry (SpO2) in combination with cardiotocograghy (CTG), improves the assessment of the intrapartum fetal condition. STUDY DESIGN: Four expert obstetricians individually evaluated 119 cases that were monitored during labor: during the first session the CTG data were available, and in the second session CTG and SpO2 data were evaluated. They were instructed to indicate the need for intervention and to estimate the umbilical artery pH. RESULTS: In the non-acidotic group (umbilical artery pH > or = 7.15, n = 112) the average(+/-S.D.) number of interventions decreased from 27(+/-17) to 16(+/-9) when SpO2 was available. This reduction in number of interventions resulted in an significantly increased specificity for two referees. In the acidotic group (n = 7) the average number of interventions also decreased, from 6(+/-2) to 4(+/-2), and as a consequence the sensitivity decreased. The pH estimate based on CTG + SpO2 was higher in both acidotic and non-acidotic fetuses than the estimated pH based on CTG alone. CONCLUSION: In this study all referees intervened less frequently when SpO2 was used as an adjunct to CTG. This resulted in fewer unnecessary operative interventions, but may also lead to unidentified fetal acidosis. The number of acidotic newborns (n = 7) was too small, however, to draw definite conclusions. Larger studies should address the efficacy of SpO2 in detecting fetal compromise before clinical use can be advocated.

Cardiotocography↗
PubMed1998

Towards multi-patient leadless and wireless cardiotocography via RF telemetry.

During labour the condition of the fetus is monitored by a cardiotocograph which displays fetal heart rate and a measure of uterine contractions. Ultrasound and tocodynamometer transducers are placed on the mother's abdomen and connected to a bedside monitor and display unit via a cable. This paper describes a prototype wireless system aimed at demonstrating the potential elimination of the cable which is undesirable in a number of respects. The radio link utilised operates at a frequency of 418 MHz with data compression and time division multiplexing (TDM) employed to allow up to 10 units to operate simultaneously on the same frequency in the same area. Data compression is achieved by extracting the Doppler ultrasound signal envelope and representing the frequency content of the signal using a zero crossing counting technique. Two Medium Access Control (MAC) protocols were considered, with a synchronised time division multiplexing system shown to offer greater throughput and resistance to interference than Carrier Sense Multiple Access (CSMA). This wireless RF telemetry system could be readily adapted for other multi-patient monitoring applications.

Cardiotocography↗
PubMed1996

[Prognostic value of cardiotocography in pregnancy with pathologic Doppler findings].

Absent (absent-EDF) or reversed (RF) end-diastolic flow in Doppler velocimetry in the umbilical artery and fetal aorta indicates highly disturbed fetoplacental perfusion, which often occurs early in pregnancy. Perinatal mortality and morbidity is very high. In this situation it is not clear how long pregnancy can be continued to achieve better conditions for the preterm fetus. This study was performed to investigate the value of fetal heart rate recordings (FHR) in patients with absent EDF or RF as a parameter to determine the optimum time of delivery. 25 pregnancies with absent (n = 21) or reversed end-diastolic velocity (n = 4) were analysed. Gestational age was between 24 and 34 weeks. 17 children showed compensatory dilatation of the middle cerebral artery (68%). 15 (60%) were growth retarded, 8 of them below the 3% percentile, while 3 had normal weight. Maximum time interval until delivery was 18 days, median was 2 days. Five children died before, 2 during delivery. As none died after delivery, perinatal mortality was 28%. 4 of the survivers (22%) showed arterial acidosis. Only three children had completely normal fetal heart rate recordings on the day of diagnosis of absent EDF or RF. All others showed at least suspicious FHR (according to Hammacher), 8 of them (32%) even pathological FHR, including all children who died later. Early suspicious changes in FHR were the reduction in frequency and amplitude of oscillation, while decelerations occurred later. Additional unfavourable parameters in FHR were roundings of the oscillatory inversions as well as missing reactivity to fetal movements. Fetal heart rate monitoring is a reliable tool for determination of the optimum time of delivery in children with absent EDF or RF. The decision has to be made in relation to the gestational age. If possible, the fetus should be born before FHR becomes pathological. In this manner perinatal mortality and morbidity should be kept at a low level even in high-risk patients with absent EDF or RF.

Blood Flow Velocity↗
PubMed1991

[Pathologic Doppler flow findings and cardiotocography results].

Of 1950 pregnant patients (2870 Doppler ultrasound measurements) we observed, in a study group with highly abnormal Doppler-flow findings (n = 66, Feb. 1990), a correlation of Doppler flow and FHR-recordings. Among these 66 patients we retained 60 (91%) in the hospital. They had at least 2 FHR-recordings a day. The results of Doppler flow measurements in the fetal aorta and umbilical artery correlated well with diagnosis of IUGR. The comparison of the overall results of both fetal vessels did not indicate any significant difference. In 21% of all patients with highly abnormal Doppler flow findings, was no abnormal FHR record until delivery. 26% already showed an abnormal non-stress test before the first pathological Doppler assessment, in 44% abnormal FHR-recordings were observed later than the first abnormal Doppler flow finding in the course of pregnancy. The median interval was 13.5 days in cases with increased Doppler flow parameters but with detectable end-diastolic blood flow and was reduced to 8 days in cases with absent end-diastolic blood flow. In 9% of all cases, abnormal results were found with both methods on the same day. In 32% we observed a reproducible notch in Doppler flow velocimetry of uteroplacental vessels. The rate of congenital malformations was 14%. Thus abnormal Doppler flow signals can be estimated as "early" prognostic criterias for a compromised fetus at risk.

Birth Weight↗
PubMed1990

[Heat flux measurements of the fetal scalp and cardiotocography in predicting acidosis states sub partu--a comparison of 2 methods].

Although the efficacy of electronic foetal heart rate (FHR) monitoring and intermittent scalp blood sampling is well established, these methods still result in a considerable number of false positive and negative predictions. Consequently, methods, which improve the accuracy of prediction, are still under study. Heat flux measurements from the foetal scalp have been shown to relate to the metabolic condition of the foetus during delivery. In this study, we investigated the predictive power of measuring scalp heat flux and monitoring the FHR electronically, and the combination of both. In 136 foetuses the scalp heat flux was measured by means of a heat flux transducer, 2.5 cm in diameter, attached to the foetal scalp after the cervix had dilated to greater than 2.5 cm. Heat flux was regarded as abnormal, if the heat flux was less than 10 w/m2 or greater than 21 w/m2, or fell by more than 20% of its initial value during the last 30 min before delivery. FHR tracings were considered abnormal, if they resulted in therapeutic consequences like oxygen mask for the mother, scalp blood sampling or immediate operative delivery. Foetuses were considered acidotic, if their pH in the arterial cord blood was less than 7.20. Accuracy of prediction was described by appropriate parameters. The scalp heat flux method resulted in a higher specificity (80.4% vs. 72.5%), positive predictive value (59.2% vs. 51.7%), and overall accuracy (82% vs. 77%) than FHR monitoring. Sensitivity of FHR monitoring was slightly higher than the one of heat flux method (88.2% vs 85.3%). Combining both methods resulted in a sensitivity of 100% thus detecting all acidotic foetuses, but specificity fell to 62%.(ABSTRACT TRUNCATED AT 250 WORDS)

Acidosis↗
PubMed2005

Doppler, cardiotocography, and biophysical profile changes in growth-restricted fetuses.

OBJECTIVE: To assess from diagnosis to delivery the Doppler studies of the umbilical artery, middle cerebral artery, umbilical vein, ductus venosus, and amniotic fluid index of fetuses with idiopathic growth restriction. METHODS: A total of 145 singleton growth-restricted fetuses with abnormal umbilical artery pulsatility indexes were studied. Cesarean delivery was performed because of abnormal biophysical profile or nonreassuring fetal heart rate pattern. RESULTS: There were 4 fetal and 50 neonatal deaths. Two growth-restricted groups were identified: Group A (n = 44) included fetuses in whom all measures became abnormal preceding an abnormal biophysical profile or nonreassuring nonstress test. Group B (n = 101) included fetuses in whom 1 or more measures were normal at the time of cesarean delivery. There was no statistically significant difference in perinatal morbidity and mortality between the 2 groups. Neonatal death was increased in fetuses with umbilical artery reversed flow (odds ratio 2.34, 95% confidence interval 1.16-4.73; P < .05) and ductus venosus reversed flow (odds ratio 4.18, 95% confidence interval 2.01-8.69; P < .05). A significant correlation was also found between low birth weight and adverse perinatal outcome. CONCLUSION: In fetuses with idiopathic growth restriction, 1) low birth weight, 2) umbilical artery reversed flow, and 3) ductus venosus absent or reversed flow are associated with an increased perinatal morbidity and mortality.

Analysis of Variance↗
PubMed1995

The prediction of fetal acidosis at birth by computerised analysis of intrapartum cardiotocography.

OBJECTIVE: To assess the capability of a computer software interpretation program, using intrapartum fetal heart rate and intrauterine pressure as recorded in a cardiotocogram to predict fetal acidosis at birth. DESIGN AND SUBJECTS: A retrospective analysis of digitised fetal heart rate and uterine activity values obtained from 73 high risk women in labour. SETTING: Two university teaching hospitals. METHODS: A computer software program was constructed to analyse the digitised data and predict acidosis. The results of the analysis were compared with actual umbilical arterial blood pH and base excess at delivery. RESULTS: The software cardiotocogram interpreter was able to predict a pH of less than 7.15 with an accuracy of 77%, a sensitivity of 88% and specificity of 75% in this set of data. It was able to predict a base excess of less than -8 mmol/l with an accuracy of 81%, a sensitivity of 76% and specificity of 82%. CONCLUSIONS: A computerised method of analysing fetal heart rate and uterine activity using a simple algorithm has demonstrated a capability to predict fetal acidosis at the time of delivery. Further research in this area is warranted.

Acidosis↗