Clinical Trial Details
— Status: Withdrawn
Administrative data
NCT number |
NCT03996317 |
Other study ID # |
5190191 |
Secondary ID |
|
Status |
Withdrawn |
Phase |
N/A
|
First received |
|
Last updated |
|
Start date |
June 2021 |
Est. completion date |
December 30, 2022 |
Study information
Verified date |
August 2021 |
Source |
Loma Linda University |
Contact |
n/a |
Is FDA regulated |
No |
Health authority |
|
Study type |
Interventional
|
Clinical Trial Summary
Hyperoxygenation for resuscitation of abnormal fetal heart rate tracings has been routine
obstetric practice. However, there have not been any studies to support this practice. Recent
literature have either found no associated benefit to intrapartum maternal oxygen
administration, or in a number of studies demonstrated higher risk of neonatal complications.
Despite these studies, the evidences have not been adequate to change the clinical practice
because the majority of these studies either focused on biological differences rather than
clinical outcomes data or were retrospective rather than randomized trials. Therefore, the
investigators propose a large single center randomized clinical trial to determine the
effects of maternal hyperoxygenation therapy for the treatment of fetal heart rate tracing
abnormalities.
Description:
Continuous fetal heart rate tracing is part of the standard practice during intrapartum
obstetric management. The goal of fetal heart rate monitoring is to identify early signs of
fetal distress during labor, initiate effective interventions to improve fetal outcomes and
reduce the risk of cesarean and operative vaginal delivery, and when interventions fail to
improve the fetal status, to help guide the decision to proceed with operative delivery in
order to minimize fetal/neonatal morbidity as a result of fetal intolerance to labor.
There are four major components to fetal heart tracing that guide obstetric management:
baseline, variability, acceleration, and deceleration (uterine contraction pattern is also
assessed to guide management). When one or more of these components are outside of normal
values, it may be associated with fetal hypoxemia/acidemia. The typical management of these
abnormal findings include maternal reposition, IV fluid bolus, increase maternal blood
pressure, stopping uterine contractions, amnioinfusion, and maternal oxygen. The goal of
therapy is to increase maternal blood flow to the uterus and therefore improve
maternal-placental perfusion, increase oxygen delivery to and carbon dioxide removal from the
fetus.
Maternal oxygenation is part of the standard management of fetal tracing abnormalities
nationwide, and is part of the American College of Obstetricians and Gynecologists (ACOG)
guideline for this specific indication. Its use intuitively make sense, as one of the major
concerns with fetal tracing abnormalities is the development of fetal hypoxemia leading to
anaerobic metabolism and the ensuing development of metabolic acidosis. However, clinical
evidence to support its use is lacking. This is partly due to the long-ingrained culture of
routine oxygen delivery on Labor and Delivery across the country, therefore no clinical
trails were considered until recently. More importantly, from a physiologic standpoint, the
fetal hemoglobin has significantly higher oxygen affinity compared to adult hemoglobin.
Therefore, increasing maternal oxygen saturation does not lead to significant change in fetal
oxygen saturation in general. In addition, some of the reasons for the development of fetal
hypoxemia and acidemia are due to placental insufficiency or umbilical cord compression. In
these circumstances, there is limited oxygen delivery in the fetal circulation at the
maternal-fetal interface and therefore maternal oxygen therapy will have limited effects on
fetal oxygenation.
Furthermore, there is growing concern regarding the potential risks associated with
supraphysiologic oxygen levels. At a cellular level, hyperoxygenation increased the
production of oxygen free radicals, which results in cell damage. This is reflected in the
neonatal literature regarding hyperoxygenation during neonatal resuscitation, including
higher risk for respiratory and neurologic complications, the American Academy of Pediatrics
(AAP) no longer recommend initial neonatal hyperoxygenation during resuscitation. There are
similar concerns in oxygen use during obstetric management in recent literature. A number of
studies have demonstrated higher risk of neonatal complications associated with maternal
intrapartum hyperoxygenation (3-6). However, the evidences have not been adequate to change
the clinical practice because the majority of these studies either focused on biological
differences rather than clinical outcomes data or were retrospective rather than randomized
trials.
Given the ingrained nature of maternal oxygen therapy, the lack of clinical evidence in favor
of its use, and concerns regarding potential harm, large scale clinical trials are needed to
assess the risks and benefits of the current standard practice. Therefore, the investigators
propose a large single center randomized clinical trial to determine the effects of maternal
hyperoxygenation therapy for the treatment of fetal heart rate tracing abnormalities.
Trial interventions include the following:
Fetal heart rate abnormalities include one or more of the following:
Recurrent decelerations: more than 2 in a 20 minute period Minimal or absent variability
Fetal bradycardia Fetal tachycardia
Routine fetal resuscitation measures will be taken for fetal heart rate abnormalities at the
discretion of the obstetric team. These may include:
Maternal repositioning IV fluid bolus Anesthesiology management of hypotension Stopping
oxytocin infusion Administering Terbutalin Amnioinfusion Operative vaginal delivery Cesarean
delivery In addition to above management options, patient will be assigned to one of two
treatment arms through computerized randomization Treatment arm 1 Routine labor management at
the discretion of the obstetric team Maternal oxygenation with 10L non-rebreather mask will
be given with any above fetal heart rate abnormalities.
Maternal oxygenation is discontinued at the resolution of fetal tracing abnormality or after
delivery.
Treatment arm 2 Routine labor management at the discretion of the obstetric team Maternal
oxygenation is withheld unless indicated for maternal pulse oximetry is less than 92%