Maternal and Neonatal Outcomes of the Use of Vasopressors to Treat Hypotension During Spinal Anesthesia for Cesarean
Information source: Instituto Materno Infantil Prof. Fernando Figueira
Information obtained from ClinicalTrials.gov on February 07, 2013
Link to the current ClinicalTrials.gov record.
Condition(s) targeted: Preeclampsia; Pregnancy Toxemias
Intervention: Metaraminol (Drug); Ephedrine (Drug)
Phase: Phase 3
Sponsored by: Instituto Materno Infantil Prof. Fernando Figueira
Official(s) and/or principal investigator(s):
Antonio Monteiro, MD, Study Director, Affiliation: Instituto de Medicina integral Professor Fernando Figueira
Flavia Orange, PhD, Phone: 558132668177, Email: firstname.lastname@example.org
Anesthesia for cesarean section has been a great challenge for the anesthesiologist, for
mother and fetus are closely related. So the challenge is to anesthetize the mother without
interfering with the physiology of the fetus. The spinal block, although safe, are not free
of complications if not treated properly, may be responsible for increased fetal morbidity.
Among the major side effects, there is hypotension, with potentially serious consequences
for the maternal-fetal dyad. Hypotension in pregnant women at low risk may not lead to major
damage, but a pregnant woman with low reserves, as is the case of pregnant women with
pre-eclampsia, any drop in blood pressure of the mother can bring harm to the welfare of
mother and fetus. Based on the above, the purpose of this study is to compare the effects of
maternal and perinatal treatment of hypotension with ephedrine or metaraminol in pregnant
women with severe preeclampsia undergoing cesarean section under spinal anesthesia. There
will be a randomized, double-blind, which will be included pregnant women with severe
preeclampsia with indication of cesarean section, gestational age above 34 weeks gestation
and only. Will be Excluded women with hemorrhagic syndromes of pregnancy, HELLP syndrome,
eclampsia, cardiovascular or cerebrovascular disease, fetal distress and absolute
contraindications to spinal anesthesia.
All patients are fully informed of the research objectives and will only be included in the
study if they agree to participate and sign the Instrument of Consent. The project was
designed following the recommendations of Resolution 196/96 of the National Health and the
Declaration of Helsinki for research involving human subjects (2000). In addition, the
project was submitted to the Ethics Committee in Research of the Institute of Integrative
Medicine Professor Fernando Figueira, is approved. The study will be conducted from June
2011 to July 2012. The study variables are: consumption of metaraminol and ephedrine before
and after birth, the occurrence of nausea and vomiting, incidence of maternal hypotension,
the occurrence of reactive hypertension, occurrence of bradycardia, pH of umbilical cord,
Apgar score 5 minutes, need for face mask ventilation and ICU admission.
Official title: Maternal and Neonatal Outcomes After the Use of Vasopressors to Correct Hypotension During Cesarean Section Under Spinal Anesthesia in Pregnant Women With Severe Preeclampsia: Randomized Clinical Trial
Study design: Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Single Group Assignment, Masking: Double Blind (Subject, Investigator), Primary Purpose: Treatment
Primary outcome: Incidence of maternal hypotension
Secondary outcome: Maternal and Neonatal outcomes
Ephedrine, a long time was considered the safest drug for both mother and fetus during the
treatment of hypotension in Caesarean section. However, recent evidence shows that contrary
to what was thought, ephedrine appears to increase fetal metabolism, decreasing the pH and
Recently, phenylephrine has been used in the treatment of hypotension during cesarean
delivery with better results in relation to acid-base parameters in umbilical cord blood.
However, few data are available on the use of phenylephrine in high-risk pregnancy, the
majority of studies in healthy pregnant women for elective caesarean section.
Although little scientific evidence regarding the use of metaraminol for treatment of
hypotension in Caesarean section, recent study demonstrated superiority of this drug
compared to ephedrine, checking a lower incidence of neonatal acidosis and better control of
blood pressure. The researchers also found differences in blood gases from the umbilical
cord between the ephedrine and metaraminol groups larger than those already found in
previous studies comparing ephedrine and phenylephrine.
The pathophysiological changes in patients with pre-eclampsia can lead to intrauterine
growth restriction with chronic fetal distress, due to the limited uteroplacental flow,
which, in certain situations, may be reduced by 50% to 70%. Added to this, spinal anesthesia
may cause sudden hypotension and fetal acidosis more often, even in elective operations,
compared to epidural or general anesthesia, and that these changes may not have clinical
significance in healthy fetuses at term, but may be critical in situations where arterial
insufficiency uteroplacental and fetal distress already to present. It is believed,
therefore, important that treat or prevent hypotension in patients with severe preeclampsia
under spinal anesthesia.
Prevention of hypotension in patients with severe preeclampsia does not require large
amounts of intravenous fluids, but careful prophylaxis of postural hypotensive syndrome.
Despite the care, if hypotension occurs, aggressive treatment is mandatory in these patients
and fast in order to avoid worsening fetal distress and neonatal depression. Such patients
are more sensitive to vasopressors, therefore, small doses should be administered.
However, the biggest challenge of the anesthesiologist is to determine the ideal vasopressor
in pregnant women at high risk, able to adequately restore blood pressure levels without
determining deterioration of fetal status.
30 Reynolds and Seed in 2005 showed that ephedrine, administered in large doses, has
contributed to the adverse effects of spinal anesthesia (greater degree of fetal metabolic
acidosis), supporting the idea that ephedrine is not the vasopressor of choice for treatment
of maternal hypotension during cesarean section.
As a result, this study is to fill this knowledge gap, taking on great importance to
evaluate maternal and perinatal outcomes of pregnant women with severe preeclampsia to
receive ephedrine or metaraminol for treatment of maternal hypotension during caesarean
section under spinal anesthesia. Considering the importance of creating a protocol, since
the metaraminol, unlike phenylephrine, is widely available at our facility.
Minimum age: 18 Years.
Maximum age: 45 Years.
- Severe preeclampsia with indication of cesarean section
- Informed consent for study participation
- Age above 34 weeks gestational
- Single Pregnancy
- Hemorrhagic syndromes of pregnancy (placenta previa, DPPNI)
- Help Syndrome
- Cardiovascular or Cerebrovascular Disease
- Fetal distress Absolute contraindications to spinal anesthesia (coagulopathy, sepsis
- Pregnant unable to decide on participation in the study (unconscious, confused, coma,
Locations and Contacts
Flavia Orange, PhD, Phone: 558132668177, Email: email@example.com
Instituto de Medicina Integral Professor Fernando Figueira, Recife, Pernambuco 52050050, Brazil; Recruiting
Leila Katz, PhD, Phone: 558188585977, Email: firstname.lastname@example.org
Melania Amorim, PhD, Phone: 558188221514, Email: email@example.com
Flavia Orange, PhD, Principal Investigator
Starting date: June 2011
Last updated: October 13, 2011