Infant outcome at four years of age after intrapartum sampling of scalp blood lactate for fetal assessment. A cohort study

Can lactate be valuable in early diagnosis and prognosis of neonatal sepsis?

Background

Sepsis monitoring tissue perfusion is crucial for detecting circulatory failure early, implementing the right treatments, and assessing response. Insufficient oxygenation leads to a rise in lactate level and has been shown to be useful in predicting mortality and morbidity in newborns. There have not been many studies on how lactate measurement affects neonatal sepsis diagnosis and prognosis.

Aim

The aim of our study was to determine the impact of lactate on early diagnosis and prognosis in neonatal sepsis.

Materials and Methods

Eighty-seven newborns diagnosed with neonatal sepsis at a neonatal intensive care unit between January 2010 and July 2021 were included in the study. Venous blood gas, lactate, and C-reactive protein (CRP) levels and complete blood count on the first, second, and third day of hospitalization were noted. Lactate values were correlated with other variables to determine the impact of hyperlactatemia on morbidity and to determine factors affecting the length of stay. IBM SPSS Statistics version 22.0 for Windows was used to analyze the data (SPSS Inc., Chicago, IL, United States).

Results

A strong negative correlation between lactate and oxygenation and perfusion indicators (HCO3, BE, PaO2) during the therapeutic process was observed. With treatment, the initial measured lactate value decreased, and a significant increase in CRP and oxygen saturation was observed, which was interpreted as the observation of an early lactate response to infection before a CRP response. The initial lactate level, as well as the change in lactate levels, was not, however, significantly correlated with the length of stay.

Conclusion

Lactate can be used in the early diagnosis of neonatal sepsis and for determining prognosis.

Proposed cutoff for fetal scalp blood lactate in intrapartum fetal surveillance based on neonatal outcomes: a large prospective observational study

OBJECTIVE

Determination of lactate in fetal scalp blood (FBS) during labour has been recognised since the 1970s. The internationally accepted cutoff of >4.8 mmol/l indicating fetal acidosis is exclusive for the point-of-care device (POC) LactatePro™, which is no longer in production. The aim of this study was to establish a new cutoff for scalp lactate based on neonatal outcomes with the use of the StatstripLactate^® /StatstripXpress^® Lactate system, the only POC designed for hospital use.

DESIGN

Observational study.

SETTING

January 2016 to March 2020 labouring women with indication for FBS were prospectively included from seven Swedish and one Australian delivery unit.

POPULATION

Inclusion criteria: singleton pregnancy, vertex presentation, ≥35⁺⁰  weeks of gestation.

METHOD

Based on the optimal correlation between FBS lactate and cord pH/lactate, only cases with ≤25 minutes from FBS to delivery were included in the final calculations.

MAIN OUTCOME MEASURES

Metabolic acidosis in cord blood defined as pH <7.05 plus BD_ecf >10 mmol/l and/or lactate >10 mmol/l.

RESULTS

A total of 3334 women were enrolled of whom 799 were delivered within 25 minutes. The areas under the receiver operating characteristics curves (AUC) and corresponding optimal cutoff values were as follows; metabolic acidosis AUC 0.87 (95% CI 0.77-0.97), cutoff 5.7 mmol/l; pH <7.0 AUC 0.83 (95% CI 0.68-0.97), cutoff 4.6 mmol/l; pH <7.05 plus BD_ecf ≥12 mmol/l AUC 0.97 (95% CI 0.92-1), cutoff 5.8 mmol/l; Apgar score <7 at 5 minutes AUC 0.74 (95% CI 0.63-0.86), cutoff 5.2 mmol/l; and pH <7.10 plus composite neonatal outcome AUC 0.76 (95% CI 0.67-0.85), cutoff 4.8 mmol/l.

CONCLUSION

A scalp lactate level <5.2 mmol/l using the StatstripLactate^® /StatstripXpress^® system will safely rule out fetal metabolic acidosis.

TWEETABLE ABSTRACT

Scalp blood lactate <5.2 mmol/l using the StatstripLactate^® /StatstripXpress system has an excellent ability to rule out fetal acidosis.

Fetal lactate levels align with the stage of labour

AIM

To evaluate the association between lactate concentrations in fetal blood samples and the different advanced labour stages.

METHODS

Eighteen-month prospective population-based clinical study of 187 singleton pregnant women in labour who were monitored by fetal blood sampling (FBS) because of non-reassuring intrapartum CTG results at Kuopio University Hospital, Finland. Peripheral lactate concentration and pH were analysed at different stages of labour and in umbilical arterial samples immediately after delivery.

RESULTS

FBS samples (N = 350) were obtained from 5.4 % of all women in labour during the study period, and 48 % had spontaneous delivery, 27 % had vacuum-assisted vaginal delivery, and 25 % had nonelective Caesarean delivery. FBS lactate levels increased 4-11% with every 1-2 cm of cervical dilation and 18 % from early labour to fully dilated cervix. In 42 women with at least two FBSs, lactate levels increased significantly from the early I stage of labour and up to a fully dilated cervix. Lactate values were significantly higher in umbilical arterial samples compared to FBSs. Sensitivity of the highest FBS lactate values for the detection of birth asphyxia were considerably low varying between 42.9-57.1%.

CONCLUSION

FBS lactate levels were related to the stage of labour during vaginal delivery attempt. Wide range of lactate levels during labour complicates its use as a predictor of birth asphyxia.

Intrapartum fetal blood sampling performed at early cervical dilatation and delivery outcomes

BACKGROUND

Intrapartum fetal blood sampling (FBS) is a fetal well-being diagnostic test for cardiotocogram abnormalities.

AIM

The aim of this study was to determine whether women who had their first FBS at <4 cm cervical dilation had an increased risk of operative delivery (caesarean section, instrumental delivery) compared to those women who had their first FBS ≥ 4 cm dilation.

MATERIALS AND METHODS

Retrospective cohort study involving labouring women who underwent FBS in a tertiary centre between 2015 and 2017. Women who had their first FBS at <4 cm dilation were compared to those who had their first FBS at ≥4 cm. The primary outcome was operative delivery (caesarean, instrumental delivery); secondary outcomes were neonatal complications. Univariate logistic regression was used to assess the association between degree of cervical dilation at first FBS and study outcomes.

RESULTS

Among 591 women, 39 (6.6%) had their first FBS at <4 cm cervical dilation. Women in the ≥4 cm group were less likely to have a total of ≥2 FBS (P = 0.003). There was no difference in the primary outcome between the two groups. Women who had the first FBS at <4 cm dilation were twice as likely to have a caesarean section delivery (odds ratio 2.06, 95% confidence interval 1.06-3.98), although 41% had a vaginal birth (instrumental and spontaneous). There were no differences in rates of resuscitation or admission to nursery between groups.

CONCLUSION

Women who had their first FBS < 4cm cervical dilation were twice as likely to have a caesarean section compared to women who had their first FBS ≥ 4 cm. However, 41% had a vaginal birth, and there were no differences in fetal outcomes.

Effectiveness of fetal scalp stimulation test in assessing fetal wellbeing during labor, a retrospective cohort study

BACKGROUND

It is discussed whether fetal scalp stimulation (FSS) test is a reliable complimentary tool to cardiotocography (CTG) to assess fetal wellbeing during labor. The test is based on the assumption that a well-oxygenated fetus, in contrast to the depressed fetus, will respond to a certain stimulus. The aim of this study was to investigate the effectiveness of the FSS-test.

METHODS

A retrospective observational study carried out Copenhagen University Hospital, Herlev, Denmark. Laboring women with singleton pregnancies in cephalic presentation after gestation week 33 and indication for fetal blood sampling (FBS) were eligible for inclusion. The FSS-test was classified as positive when an acceleration was absent at the time of FBS and negative when an acceleration was present. Lactate in scalp blood was measured by the point-of-care device LactatePro™ and pH in artery umbilical cord blood by the stationary blood gas analyzer ABL800. Lactate level < 4.2 mmol/L in scalp blood and arterial cord pH > 7.1 were cut-offs for normality.

RESULTS

Three hundred eighty-five women were included. The cohort was divided by the FBS-to-delivery time: Group 1 (n = 128) ≤ 20 min, Group 2 (n = 117) 21-59 min and Group 3 (n = 140) ≥ 60 min. The proportion of FSS-positive tests differed significantly between the groups (p < 0.000). In Group 1 the sensitivity, specificity and likelihoods for scalp lactate ≥4.2 mmol/L were 81.5 (95% CI 67-90.1), 13.3 18.5 (95% CI 5.9-24.6), LHR+ 0.94 (95% CI 0.8-1.1) and LHR - 1.4 (95% CI 0.6-3.2) and for umbilical artery pH ≤ 7.10 the values were 82.6% (95% CI 61.2-95.1), 16% (95% CI 9.4-24.7), 1.0 (95% CI 0.8-1.2) and 1.1 (95% CI 0.4-3) respectively. Regardless of the FBS-to-delivery time the LHR+ for lactate ≥4.2 mmol/L increased to 1.38 (95% CI 1.2-1.6).

CONCLUSION

The effectiveness of scalp stimulation test was poor for both ruling in and out fetal hypoxia during labor. Absence of a provoked acceleration seems to be a normal phenomenon in the second stage of labor.

Blood Glucose and Lactate Levels and Cerebral Oxygenation in Preterm and Term Neonates-A Systematic Qualitative Review of the Literature

Background: Cerebral oxygenation monitored non-invasively by near-infrared spectroscopy (NIRS) is of increasing interest in neonatal care. Cerebral oxygenation is determined by cerebral oxygen delivery and cerebral oxygen consumption. Oxygen delivery as well as oxygen consumption might be influenced by metabolic parameters like blood glucose and lactate. Objective: The aim of the present systematic qualitative review is therefore to identify and summarize all studies, which describe cerebral oxygenation measured with NIRS and blood glucose and/or blood lactate levels in neonates. Data sources: A systematic search of Ovid Embase and PubMed was performed. Search terms included near-infrared spectroscopy, fractional tissue oxygen extraction, cerebral tissue oxygen saturation, regional cerebral tissue oxygen saturation, oxygenation, term, and preterm neonates, cesarean delivery, transition, after-birth, newborn, vaginal delivery, cesarean delivery, baby, neonatal transition, metabolism, lactate, glucose, and blood glucose level. Study selection/data synthesis: Studies analyzing cerebral oxygenation and blood glucose and/or blood lactate levels in neonates were included. Animal studies, duplicates, or studies in non-English language were excluded. Results: Twenty-five studies were identified that describe blood glucose and/or blood lactate levels as primary or secondary outcome parameters with additional measured cerebral oxygenation by NIRS in neonates. Twelve studies were included with blood glucose measurements: four described an association between blood glucose levels and cerebral oxygenation, two show no association, and six do not report on possible associations. Eighteen studies were included with lactate measurements: one describe an association between lactate levels and cerebral oxygenation, while three show no association and 14 do not report on possible associations. Discussion: The influence of blood glucose and blood lactate levels on the cerebral oxygenation in neonates is still controversial. However, there seems to be an association between cerebral oxygenation and the metabolic parameter blood glucose and lactate, which need further investigation.

Foetal scalp blood sampling and ST-analysis of the foetal ECG for intrapartum foetal monitoring: a restricted systematic review

BACKGROUND

To investigate if foetal scalp blood sampling (FBS) is useful in preventing foetal metabolic acidosis in labour when ST-analysis of the foetal ECG (STAN ® ) is already being used as a second line technique for intrapartum foetal monitoring with cardiotocography (CTG).

DESIGN

Restricted systematic review.

METHODS

Based on a literature search in July 2019, a restricted systematic review was performed. Studies comparing CTG+STAN ® +FBS with CTG+STAN ® , CTG+FBS or CTG only were included. Observational studies allowing FBS in addition to STAN ® reporting the indications, results and neonatal outcomes were included as well.

RESULTS

Five randomised controlled trials (RCT) and seven observational trials were analysed. Based on the analysis of data coming from one RCT, FBS identifies foetal acidosis in 9.9% when performed in specific situations. Similarly, in observational trials it was found that in up to 10% of cases where STAN ® registration was less reliable, FBS suggested foetal acidosis. However, there is no evidence that FBS in these cases was capable of preventing metabolic acidosis or its neurological consequences.

CONCLUSION

Based on the available literature, no recommendations in favour of combining FBS with STAN ® monitoring can be made.