Cardiac Output Changes in Cesarean Section

Hemodynamic Instability Clinical Trial

Official title:

Comparison of Norepinephrine and Phenylephrine in Cesarean Section by Transesophageal Ultrasound

Clinical Trial Details — Status: Not yet recruiting

Administrative data

• NCT number: NCT02759510
• Other study ID #: Renji-2016035k
• Status: Not yet recruiting
• Phase: Phase 0
• First received: April 29, 2016
• Last updated: May 2, 2016
• Start date: June 2016
• Est. completion date: June 2017

Study information

• Verified date: April 2016
• Source: RenJi Hospital
• Contact: Qionghui Zhan, MD
• Phone: 8621-34506285
• Email: zhanqionghui328[@]163.com
• Is FDA regulated: No
• Health authority: China: Ethics Committee
• Study type: Interventional

Clinical Trial Summary

Since 2011, phenylephrine was recommended as the preferred drug to maintain blood pressure in obstetric anesthesia.Phenylephrine, an α adrenoceptor agonist, can induce peripheral vasoconstriction to maintain blood pressure, while reflexly decrease heart rate and result in cardiac output (CO) reduction.Norepinephrine acts not only as an α adrenoceptor receptor agonist, but also as a weaker β adrenergic receptor agonist. It can elevate blood pressure the same asphenylephrine, meanwhile produce positive inotropic effect including increasing heart rate.Thus, the administration of norepinephrine can maintain blood pressue and avoid the decline of CO. The purpose of this study is to evaluate the effect of norepinephrine and phenylephrine on maternal CO in cesarean section by transesophageal echocardiography.

Description:

Combined spinal epidural anesthesia (CSEA) is a commonly used anesthetic methods in cesarean section. The main problem of CSEA is hypotension, which will cause maternal nausea and vomiting, reduced uteroplacental blood flow and fetal acidosis. One of the important methods for prevention and treatment of hypotension after CSEA is to give vasoactive drugs.

Since 2011, phenylephrine was recommended as the preferred drug to maintain blood pressure in obstetric anesthesia.Phenylephrine, an α adrenoceptor agonist, can induce peripheral vasoconstriction to maintain blood pressure, while reflexly decrease heart rate and result in cardiac output (CO) reduction.Dyer et al. used bioimpedance technique to analyze the hemodynamic changes in normal pregnant women. A bolus of 80 ug phenylephrine was administrated when maternal mean arterial pressure decreased 20% after CSEA. It was found that cardiac output (CO) decreased significantly (14%) after phenylephrine administrationcompared with the baseline.And the decrease of CO induced by phenylephrine was in a dose dependent.All the studies referred above recruitednormal pregnant women, and the decreased CO did not have an adverse effect on neonatal birth. However, as we all know, the decrease of CO will influence uteroplacental blood, which may lead to adverse results in existed intrauterine distress fetal. All authors of those studies stressed that the decrease of CO induced by phenylephrine may increase the risks of fetal distress or other adverse consequences. So, it is crucial for obstetric anesthesiologist to choose a suitable vasoactive drugs, which can maintain both maternal blood pressure and uteroplacental perfusion in order to keep intrauterine environment steady.

Norepinephrine acts not only as an α adrenoceptor receptor agonist, but also as a weaker β adrenergic receptor agonist. It can elevate blood pressure the same asphenylephrine, meanwhile produce positive inotropic effect including increasing heart rate.Thus, the administration of norepinephrine can maintain blood pressue and avoid the decline of CO. And norepinephrine is superior to phenylephrine in the respect of organ perfusion.

There is little research about the administration of norepinephrine in obstetric anesthesia.Ngan Kee et al.compared phenylephrine (0.57μg/kg/min) with norepinephrine (0.035μg/kg/min) in the treatment of hypotension in obstetric anesthesia. CO monitored by a suprasternal Doppler ultrasound every 5 minutes. CO and heart rate was significantly higher in norepinephrine group than that in phenylephrine group, while peripheral vascular resistance was significantly lower in norepinephrine group than that in phenylephrine group. And the oxygen content in umbilical venous was significantly higher in norepinephrine group, which may be related to the norepinephrine induced lower peripheral vascular resistance and high cardiac output.Monitoring of CO can give a comprehensive understanding of hemodynamics in the pregnant. It enables obstetric anesthesiologist to use liquid expansion rationally and administrate vasoactive agents properly.Although the accuracy of suprasternal Doppler ultrasound was high in that study, the interval of 5min to monitor CO may miss the rapid changes in hemodynamics of pregnant women.In the present study, we will monitor CO continuously by a small diameter (6 mm) transesophageal echocardiography, which can be retained in the patient's esophagus.

The purpose of this study is to evaluate the effect of norepinephrine and phenylephrine on maternal CO in cesarean section by transesophageal echocardiography.Fetal umbilical cord blood, neonatal 1min Apgar score, 5 min Apgar scores and neonatal plasma catecholamine concentrations will be collected to understand the effects of norepinephrine and phenylephrine on fetal.

Recruitment information / eligibility

• Status: Not yet recruiting
• Enrollment: 106
• Est. completion date: June 2017
• Est. primary completion date: June 2016
• Accepts healthy volunteers: No
• Gender: Female
• Age group: 18 Years to 40 Years

Eligibility

Inclusion Criteria:

1. age >=18 years,<=40 years;

2. height 150-180 cm;

3. weight 55-80 kg;

4. full-term gestation (>36 wk and <41 wk)

5. singleton pregnancy undergoing elective cesarean section under CSEA

Exclusion Criteria:

1. contraindications to spinal anesthesia;

2. patients with any complicated pregnancy;

3. fetal compromise;

4. need of emergency;

5. in labor

Study Design

Allocation: Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Investigator), Primary Purpose: Treatment

Related Conditions & MeSH terms

• Cardiac Output, Low
• Cardiac Output,Low
• Hemodynamic Instability
• Obstetric Labor Complications
• Obstetrical Complication of Anesthesia

Intervention

Drug:
• Norepinephrine
Hypotension (systolic BP <80% of baseline) will be treated with intravenous boluses of norepinephrine 2 µg.
• Phenylephrine
Hypotension (systolic BP <80% of baseline) will be treated with intravenous boluses of phenylephrine 40 µg.

Locations

Country	Name	City	State
n/a

Sponsors (1)

Lead Sponsor	Collaborator
RenJi Hospital

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	cardiac output		from baseline (before spinal injection) until 10 minutes after spinal injection	Yes
Secondary	systolic blood pressure		from baseline (before spinal injection) until 10 minutes after spinal injection	Yes
Secondary	heart rate		from baseline (before spinal injection) until 10 minutes after spinal injection	Yes
Secondary	Apgar score		1 min and 5 min after delivery	Yes
Secondary	Umbilical cord arterial blood pH/BE/Lac		time at delivery	Yes
Secondary	umbilical plasma catecholamine concentration		time at delivery	Yes