The Oslo Stan vs Lactate Observational Study

The Oslo Stan vs Lactate Observational Study, an Observational Study Were we Compare the Clinical Performance of Two Adjunctive Methods to CTG in Intrapartum Fetal Monitoring

The main aim of the study is to compare the clinical performance of two adjunctive methods to CTG in intrapartum fetal monitoring: FBS with measurement of scalp lactate and ST analysis of the fetal ECG.

Study Overview

• Status: Completed
• Conditions: Fetal Monitoring
• Intervention / Treatment: Diagnostic test: STAN ( St wave analysis) and fetal blood sample-lactate

Detailed Description

We use Lactate as a standard adjunctive method in our hospital but we have STAN software available ( is demasked) in our CTG monitors. We will include all women in labour with an intern scalp monitoring and analyse the CTG, the lactate samples and the STAN signals in the same patient and

• Study the relationship between the decision-to-delivery interval and neonatal morbidity in deliveries monitored by scalp lactate measurement
• Compare the diagnostic capability of both methods to identify fetuses at risk of hypoxia
• Compare the false negative alerts from both methods
• Explore the temporal and quantitative relation between fetal lactate metabolism and ST interval changes of the fetal ECG

• Study Type: Observational
• Enrollment (Actual): 694

Contacts and Locations

Study Locations

• Norway
  • Oslo, Norway, 0424
    • Oslo University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 60 years (Adult)
• Accepts Healthy Volunteers: Yes

• Sampling Method: Probability Sample

Study Population

Women in labour who are monitored with CTG and FBS scalp lactate. CTG monitoring is achieved by an internal scalp electrode combined with a pressure-sensitive external contraction transducer. FBS is performed at the decision of the obstetrician. Capillary blood is obtained from the fetal head and analyzed with a bed-side test (Lactate Pro). The monitoring procedures described above are identical with the current clinical routine at the department.

The department utilizes S31 fetal monitors (Neoventa Medical AB©, Sweden), which are equipped with the hard and software tool for ST analysis. Once the scalp electrode is attached, ST analysis will be performed and recorded continuously. ST information is blinded in labor, i.e. clinical management will only be based on CTG and FBS if indicated.

Description

Inclusion Criteria:

• Singleton pregnancy
• Cephalic presentation
• Gestational age ≥36+0 weeks at delivery
• Presence of antpartum or intrapartum risk factors for fetal hypoxia according to Norwegian guidelines and therefore indication for electronic fetal monitoring with scalp electrode .

Exclusion Criteria:

• Multiple pregnancies
• Breech presentation
• Gestational age < 36+0 weeks
• Contraindications for placement of a scalp electrode (HIV or HBV or HCV pos)

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Fetus in labour at risk of acedimia; The Group of patients studied are fetuses in labour at risk of hypoxia with internal fetal monitoring and scalp lactate bloodsamples ( standard monitoring).	Diagnostic test: STAN ( St wave analysis) and fetal blood sample-lactate; The CTG will be analysed by an expert group additional to the standard procedure that have been done in Labour already. The STAN analysis will be decrypted/ demasked anonymously by the Company producing these machines.
Fetus in labour at risk of acedemia with STAN analysis; Same group of fetuses in labour at risk of hypoxia with internal fetal monitoring and STAN analysis(ST waveform analysis of the fetal electrocardiogram, opened after study inclusion finished)	Diagnostic test: STAN ( St wave analysis) and fetal blood sample-lactate; The CTG will be analysed by an expert group additional to the standard procedure that have been done in Labour already. The STAN analysis will be decrypted/ demasked anonymously by the Company producing these machines.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Is fetal hypoxia (defined as arterial umbilical cord pH < 7,1 postpartum) superiorly identified by fetal scalp blood sampling (lactate) or ST analysis of fetal ECG	Compare the diagnostic capability of both methods to identify fetuses at risk of hypoxia (i.e.umbilical artery blood pH ≤7.1); Compare FBS lactate with STAN in order to identify the superior method to avoid cord-blood acidosis at birth (i.e.umbilical artery blood pH >7.1); Compare the true negative alerts from both methods, specificity	2019-2022
Is cord blood acidosis, measured as pH in the umbilical artery postpartum affected by the "Decision-to-delivery interval" measured in minutes from Lactate warning until delivery.	To assess the effect of increasing time interval from the objective warning of intrapartum fetal hypoxia with fetal scalp lactate ≥ 4.8mmol/l to the end of operative delivery on the percentage of moderate cord-blood acidosis at birth (i.e., umbilical artery blood pH ≤ 7.1)	2019-2022

Collaborators and Investigators

• Sponsor: Oslo University Hospital
• Collaborators: Haukeland University Hospital
• Investigators: Study Director: Jacobsen F Anne Flem, MD, PhD, OUH

Study record dates

Study Major Dates

• Study Start (Actual): September 1, 2018
• Primary Completion (Actual): December 31, 2019
• Study Completion (Actual): October 31, 2023

Study Registration Dates

• First Submitted: December 12, 2019
• First Submitted That Met QC Criteria: February 26, 2021
• First Posted (Actual): March 3, 2021

Study Record Updates

• Last Update Posted (Actual): December 4, 2023
• Last Update Submitted That Met QC Criteria: December 1, 2023
• Last Verified: December 1, 2023

More Information

Terms related to this study

• Keywords: CTG; Fetal blood sampling - Lactate; ST waveform analysis
• Other Study ID Numbers: 2017/1561

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No