Metabolic Acidosis of Newborn Clinical Trial
Official title:
Cardiotocography Combined With ST-analysis Versus Cardiotocography Combined With Scalp-pH in Deliveries With Abnormal CTG - A Randomised Trial
Hypothesis:
STAN monitoring will reduce the number of interventions because of suspected fetal asphyxia
and reduce the number of newborns with metabolic acidosis.
Primary endpoint:
1) Frequency of metabolic acidosis in the two groups, defined by pH in umbilical cord artery
< 7.05 and standard base excess <-10.
Secondary endpoints:
1. Number of intervention (VE and caesarean section) in the two groups
2. Number of pH measurements in the two groups
3. Number of neonates admitted to the neonatal department because of suspected asphyxia in
the two groups
The aim of fetal surveillance is to identify those fetuses at risk for developing damage in
newborn to term or long term damage caused by lack of oxygen during birth process.
Approximately 1/10 of all cases of paralysis due to brain damage (cerebral palsy) is
believed to be caused by lack of oxygen during birth. These can be avoided if the
investigators intervene actively in the birth before damage occurs.
CardioTocoGraphy (CTG = detection of fetal heart rate pattern and maternal uterine
contractions via electrodes on the maternal abdomen and fetal scalp) is a widely used method
of fetal surveillance. However, it can be difficult to interpret a CTG, and uncertainty in
CTG interpretation may therefore lead to increase in the number of deliveries with vacuum
suction and caesarean section. Interpretation of CTG can be improved by analyzing the
acidity of a blood sample taken from the skin of the fetal scalp. Such a scalp pH analysis
shows indirectly the fetus gets enough oxygen. Scalp pH measurement requires expertise and
requires repeated measurements if the abnormal heart rate pattern persists. This method is
the normal routine at the maternity ward at Hvidovre Hospital / Roskilde County Hospital.
The problem seems to be partially alleviated by using a newly developed method for fetal
surveillance called STAN (ST analysis). By STAN continuously recorded both CTG and fetal ECG
(electrocardiography = recording of the electrical heart activity). Simultaneously analyzes
a portion of the fetal ECG, namely ST-part because hypoxia leads to changes in it. The
technique is easy to use, since it only requires one electrode on the fetal scalp that is
placed in the same way as in ordinary CTG registration.
The value of STAN (ST analysis) was assessed in 2 randomized trials and shows: 1) A
reduction in the incidence of severe hypoxia in fetuses during labor and 2) A reduction in
frequency of redemption with suction and caesarean section due to lack of oxygen during the
birth process.
Within the last year however, there is substantial new information regarding. STAN. The
Swedish Social Board has published a newsletter (17) which describes a possible risk of
birth of asphyxiated children, some died and others have cerebral palsy. A new Finnish study
(18) suggests that there may be an increased risk of (moderate) acidosis after using STAN.
The above has led to considerable debate, not just in Sweden but also throughout Europe.
This has led to the Swedish, Danish (Newsletter 1, Annex 1b) and the common Nordic reference
group for STAN orally has announced new clinical guidelines for STAN application. A recently
held workshop in Utrecht, Holland will generate joint European guideline, these will be
sought published. Against this background it has been necessary to develop new guidelines
for the complement of scalp pH in the STAN arm of this project (Annex 1a)
Common to the above studies is that there is consistently applied scalp pH before STAN
monitoring begins. It is therefore important to elucidate whether, through the use of STAN
monitoring is needed (more than 1) FBS - and if so to what extent FBS is required.
STAN method currently winning widespread in Denmark and internationally (FDA has just
approved), notwithstanding that it is not scientifically proven that fetal monitoring with
STAN is better than the current monitoring method with scalp pH measurement. It is therefore
important to get this resolved in a randomized study in the relative expensive STAN
apparatus introduced in several places in Denmark.
This study will provide an opportunity to highlight these issues and can prepare on our way
to use STAN to prevent or significantly reduce these risks and thus justify continued STAN
use or the continued spread of STAN should not by advised.
If STAN by our method proves to be comparable with clean scalps pH measurement as an adjunct
to CTG, it will be a significant advance in fetal monitoring technology, taking thus will
have a primarily non-invasive, safe and continuous method cause less inconvenience to both
mother and child.
The study was approved by the Ethical nominee directors.
The study will include all women > 18 years in labour with a fetus in the cephalic
presentation with a gestational age of more than 36 weeks + 0, where there is the monitoring
with CTG.
Women who develop CTG changes that are interpreted as abnormal (according to STAN
(FIGO)-guidelines and the scalp pH is normal, could be included in the study. Women will be
randomised by telephone(electronic)to surveillance with eighter STAN monitoring or with CTG
and scalp pH. In the latter group STAN results will be blinded (hidden) for later analysis.
There are estimated to be 1200 women in the study and the study is expected to run for 2-3
years, preceded by a pilotproject.
During the pilot project we will follow the department's usual procedures for monitoring,
but to CTG using the STAN device with blinded/concealed ST analysis. There is expected to be
100 patients in the pilotproject. The aim is to investigate whether the calculations in the
survey stick and simultaneously train staff at the maternity ward in STAN equipment and
procedures and make them familiar with the work.
The advantage in conducting the study at the maternity ward at Hvidovre hospital is that it
is the largest birthplace in Denmark with nearly 6,000 births annually, with perhaps the
highest use of scalp pH measurements during labor. In addition, nearly 3,000 births annually
at Roskilde County Hospital, a total of 9,500 births. In addition, department and project
managers areexperienced in scientific studies on fetal monitoring.
Project participants have on their own initiative, initiated this project and has no
financial interest in the instrument companies that produce the used equipment/ appliances/
monitors.
The project has been allocated 2.5 million DKr in funding for the project from Elsass
Foundation, a private foundation with no financial interest in the project equipment/
appliances/ monitors.
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Allocation: Randomized, Endpoint Classification: Safety Study, Intervention Model: Parallel Assignment, Masking: Open Label, Primary Purpose: Treatment