Fetal scalp blood pH sampling: its value in an active obstetric unit

A Nomogram Based on a Collagen Feature Support Vector Machine for Predicting the Treatment Response to Neoadjuvant Chemoradiotherapy in Rectal Cancer Patients

BACKGROUND

The relationship between collagen features (CFs) in the tumor microenvironment and the treatment response to neoadjuvant chemoradiotherapy (nCRT) is still unknown. This study aimed to develop and validate a perdition model based on the CFs and clinicopathological characteristics to predict the treatment response to nCRT among locally advanced rectal cancer (LARC) patients.

METHODS

In this multicenter, retrospective analysis, 428 patients were included and randomly divided into a training cohort (299 patients) and validation cohort (129 patients) [7:3 ratio]. A total of 11 CFs were extracted from a multiphoton image of pretreatment biopsy, and a support vector machine (SVM) was then used to construct a CFs-SVM classifier. A prediction model was developed and presented with a nomogram using multivariable analysis. Further validation of the nomogram was performed in the validation cohort.

RESULTS

The CFs-SVM classifier, which integrated collagen area, straightness, and crosslink density, was significantly associated with treatment response. Predictors contained in the nomogram included the CFs-SVM classifier and clinicopathological characteristics by multivariable analysis. The CFs nomogram demonstrated good discrimination, with area under the receiver operating characteristic curves (AUROCs) of 0.834 in the training cohort and 0.854 in the validation cohort. Decision curve analysis indicated that the CFs nomogram was clinically useful. Moreover, compared with the traditional clinicopathological model, the CFs nomogram showed more powerful discrimination in determining the response to nCRT.

CONCLUSIONS

The CFs-SVM classifier based on CFs in the tumor microenvironment is associated with treatment response, and the CFs nomogram integrating the CFs-SVM classifier and clinicopathological characteristics is useful for individualized prediction of the treatment response to nCRT among LARC patients.

Normalized spectral power of fetal heart rate variability is associated with fetal scalp blood pH

BACKGROUND

Spectral power of fetal heart rate variability is related to fetal condition. Previous studies found an increased normalized low frequency power in case of severe fetal acidosis.

AIMS

To analyze whether absolute or normalized low or high frequency power of fetal heart rate variability is associated with fetal scalp blood pH.

STUDY DESIGN

Prospective cohort study, performed in an obstetric unit of a tertiary care teaching hospital.

SUBJECTS

Consecutive singleton term fetuses in cephalic presentation that underwent one or more scalp blood samples, monitored during labour using ST-analysis of the fetal electrocardiogram. Ten-minute continuous beat-to-beat fetal heart rate segments, preceding the scalp blood measurement were used.

OUTCOME MEASURES

Absolute and normalized spectral power in the low frequency band (0.04-0.15 Hz) and in the high frequency band (0.4-1.5 Hz).

RESULTS

In total 39 fetal blood samples from 30 patients were studied. We found that normalized low frequency and normalized high frequency power of fetal heart rate variability is associated with fetal scalp blood pH. The estimated ß of normalized low frequency power was -0.37 (95% confidence interval -0.68 to -0.06) and the relative risk was 0.69 (95% confidence interval 0.51-0.94). The estimated ß of normalized high frequency power was 0.33 (95% confidence interval 0.01-0.65) and the relative risk was 1.39 (95% confidence interval 1.01-1.92).

CONCLUSIONS

Normalized low and normalized high frequency power of fetal heart rate variability is associated with fetal scalp blood pH.

A comparison of intrapartum automated fetal electrocardiography and conventional cardiotocography-a randomised controlled study

OBJECTIVE

To examine whether intrapartum monitoring by means of automatic ST analysis (STAN) of fetal electrocardiography could reduce the rate of neonatal acidemia and the rate of operative intervention during labour, compared with monitoring by means of cardiotocography (CTG).

DESIGN

Randomised controlled trial.

SETTING

Labour ward in tertiary-level university hospital.

SAMPLE

A total of 1483 women in active labour with singleton term fetus in cephalic presentation.

METHODS

Women were randomly assigned to be monitored either by STAN or by CTG. Fetal blood sampling (FBS) was optional in both groups.

MAIN OUTCOME MEASURES

Neonatal acidemia (umbilical artery pH <7.10), neonatal metabolic acidosis (umbilical artery pH <7.05 and base excess <-12 mmol/l) and operative interventions: caesarean section rate, vacuum outlet (VO) rate and FBS rate.

RESULTS

There were no statistically significant differences between the STAN group and CTG group in the incidence of neonatal acidemia (5.8 versus 4.7%) or metabolic acidosis (1.7 versus 0.7%). The caesarean section rate (6.4 versus 4.7%) and the VO rate (9.5 versus 10.7%) were also similar in the STAN and CTG groups. The incidence of FBS was lower (P < 0.001) in the STAN group (7.0%) than in the CTG group (15.6%).

CONCLUSIONS

Intrapartum fetal monitoring by means of automatic STAN did not improve the neonatal outcome or decrease the caesarean section rate. However, the need for FBS during labour was lower in the STAN group.

Vibroacoustic and scalp stimulation

Both VAS and scalp stimulation are useful in the evaluation of fetal compromise by decreasing the number of falsely abnormal FHR tests and limiting the number of unnecessary interventions, thus improving the efficiency of antepartum and intrapartum FHR monitoring. As is true for all types of fetal assessment using FHR monitoring, VAS and scalp stimulation have limitations, and a lack of response to these methodologies does not necessarily indicate fetal acidemia. When either VAS or scalp stimulation is employed, one must take into consideration their respective predictive values (see Table 1). Fetal VAS or scalp stimulation should be considered as one facet of comprehensive fetal evaluation. When these techniques are used in this manner, the clinician evaluating the fetus in the antepartum or intrapartum period may prevent unnecessary intervention and improve maternal and neonatal outcome.

Is intrapartum vibratory acoustic stimulation a valid alternative to fetal scalp pH determination?

OBJECTIVES

To determine the association between fetal heart rate accelerations, whether spontaneous or induced by vibratory acoustic stimulation, and subsequent scalp pH values in presence of a suspicious intrapartum fetal heart rate tracing, and thereby assess the ability of accelerations to predict a concurrent normal fetal scalp blood pH.

DESIGN

Prospective observational study of 253 labours involving 421 pH samples.

SETTING

Tertiary care university hospital of Genoeva.

INTERVENTION

Vibratory acoustic stimulation through the maternal abdominal wall for five seconds prior to fetal blood sampling.

MAIN OUTCOME MEASURES

Spontaneous fetal heart rate reactivity (accelerations) in the 10 min preceding vibratory acoustic stimulation, vibratory acoustic-induced reactivity prior to fetal blood sampling, and scalp pH value.

RESULTS

The positive predictive value of a reactive fetal heart rate response after vibratory acoustic stimulation was 78% (95% CI 73-84%) and 97% (95% CI 94-99%) for scalp pH values of > 7.25 and > or = 7.20, respectively. Similar observations occurred with spontaneous reactivity. Of concern, 7 out of 31 (23%) occasions where the scalp blood pH was less than 7.20 appeared to be associated with a normal fetal heart rate response to vibratory acoustic stimulation.

CONCLUSION

Fetal heart rate acceleration induced by vibratory acoustic stimulation was significantly associated with a normal scalp blood pH higher than 7.25. However, vibratory acoustic stimulation offers no advantage over observation of spontaneous fetal heart rate tracings and cannot safely replace fetal blood sampling during labour.

Clinical overview of cardiotocography

Twenty years after its widespread introduction, the role of continuous fetal heart rate and contraction monitoring in labour (cardiotocography, CTG) remains uncertain. Although a normal pattern is very reassuring about fetal condition, the predictive value of an abnormal pattern is low. In most studies the use of CTG has been associated with an increase in intervention in labour, particularly caesarean section, without clear evidence of benefit. Fetal blood sampling is the most useful associated technique for minimizing unnecessary intervention. The relationship between fetal heart rate, fetal blood pH changes and long-term outcome remains obscure and further work to clarify this relationship is urgently needed.

Fetal acidaemia, the cardiotocograph and the T/QRS ratio of the fetal ECG in labour

OBJECTIVE

To relate the T/QRS ratio of the fetal electrocardiogram (ECG) to the cardiotocogram (CTG) and fetal pH during labour.

DESIGN

Prospective data collection from selected monitored labours.

SETTING

A postgraduate teaching hospital delivery suite.

SUBJECTS

113 women in labour at term.

MAIN OUTCOME MEASURES

Correlation of fetal T/QRS ratio values with pH values at the time of fetal blood sampling and at birth (umbilical artery blood). Comparison of the predictive values of raised T/QRS ratio and a pathological CTG for fetal acidemia.

RESULTS

Complete data sufficient for analysis was available for 51 fetal scalp blood samples and 93 umbilical artery pH samples. The median (range) of T/QRS ratio values before birth of 88 babies not requiring admission to the neonatal unit was 0.13 (0.00-0.32) with a 97.5th centile value of 0.28. T/QRS ratios did not correlate with fetal scalp pH values. Fetal scalp acidaemia (pH less than 7.20) was detected with rates of 50 and 13% respectively by a pathological CTG and by a T/QRS ratio above 0.28, the positive predictive values being 40% and 50%, respectively. There was a significant correlation between increasing T/QRS ratio and falling pH. Detection rates (sensitivities) for umbilical artery acidaemia (pH less than 7.12) were 76% and 29% whereas positive predictive values were 38% and 71% respectively for a pathological CTG and a T/QRS ratio above 0.28.

CONCLUSION

A raised T/QRS ratio (greater than 0.28) had a considerably lower detection rate for fetal acidaemia during labour than a pathological CTG.

Impact of routine fetal monitoring during labor on fetal outcome with long-term follow-up

A computerized system for the storage of antenatal, intrapartal, and neonatal data has been used since 1973. The present study evaluated the influence of changed neonatal and obstetric practices, with special regard to routine fetal monitoring. Three periods were studied: 1973-1974 (6,542 deliveries, only selected high-risk patients monitored); 1975-1976 (6,857 deliveries, high-risk patients monitored); 1977-1979 (9,638 deliveries, 90% monitored). The numbers of infants with an Apgar score less than 7 at 1 and 5 min were similar in 1973-1974 and 1975-1976, but the number was significantly reduced in 1977-1979. During the years studied, all but eight infants with an Apgar score less than 7 at 5 min participated in a scheduled long-term follow-up (at least 14 mo). In 1973-1974, 25 infants (35.2%) demonstrated neurological handicaps. In 1975-1976, 14 infants (19.2%) had sequelae; in 1977-1979, only three infants (4.6%) were damaged. Trend analysis showed a significant reduction in the number of infants with neurological sequelae through the years; the reduction was significant for premature and low-risk infants but not for mature high-risk infants. The improved short-term and long-term fetal outcomes seem to be largely a result of routine fetal monitoring with all its implications for obstetric and neonatal management; the significant reduction in neurological sequelae, even after correction for other changes in obstetric routines, supports this suggestion.