Brief Summary

Spinal anesthesia is the most common anesthetic technique for elective Cesarean delivery (CD), but the most frequent unwanted side effect is hypotension, which can cause nausea and vomiting, as well as effects on the fetus. Prevention and treatment of maternal hypotension includes intravenous fluids and vasopressors. Phenylephrine is the most common vasopressor used for this purpose. However, it has been shown to reduce maternal heart rate and cardiac output, which may be a concern in an already compromised fetus. Norepinephrine is commonly used in high concentrations in intensive care and recent studies have suggested that in low concentrations it may be a better alternative to phenylephrine in elective CD, as it does not reduce the maternal heart rate or cardiac output. The optimum bolus dose of norepinephrine to prevent hypotension after spinal anesthesia in elective CD has not been elucidated. The investigators propose this study to determine the dose that would be effective in 90% of patients (ED90). A previous study by Ngan Kee et al, using continuous infusion of norepinephrine to prevent hypotension in elective CD, suggested a potency ratio for norepinephrine to phenylephrine of approximately 16:1. Hence, the investigators hypothesise that the ED90 will be approximately 6 µg, given that the current phenylephrine bolus dose at the investigators' institution is approximately 100 µg.

Trial Health

On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment

participants targeted

Target at P25-P50 for not_applicable

Timeline

Completed

Started Jan 2016

Shorter than P25 for not_applicable

Geographic Reach

1 country

1 active site

Status

completed

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

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Study Timeline

Key milestones and dates

3 months study duration

Study Start

First participant enrolled

January 1, 2016

Completed

4 days until next milestone

First Submitted

Initial submission to the registry

January 5, 2016

Completed

8 days until next milestone

First Posted

Study publicly available on registry

January 13, 2016

Completed

2 months until next milestone

Primary Completion

Last participant's last visit for primary outcome

March 1, 2016

Completed

1 month until next milestone

Study Completion

Last participant's last visit for all outcomes

April 1, 2016

Completed

Last Updated

August 31, 2016

Status Verified

August 1, 2016

Enrollment Period

2 months

First QC Date

January 5, 2016

Last Update Submit

August 29, 2016

Conditions

Hypotension

Keywords

vasopressorblood pressureCesarean sectionspinal anesthesia

Outcome Measures

Primary Outcomes (1)

Systolic blood pressure
The primary outcome of this study will be the success/response of the norepinephrine dose to maintain the systolic blood pressure at or above 80% of baseline, from induction of spinal anesthesia to delivery of the fetus.
30 minutes

Secondary Outcomes (15)

Presence of Nausea
30 minutes
Presence of Vomiting
30 minutes
Hypertension: Systolic blood pressure at or above 120% of baseline
30 minutes
Bradycardia: Heart rate less than 50 bpm
30 minutes
Upper sensory level of anesthetic block, assessed by pinprick upon delivery
30 minutes
+10 more secondary outcomes

Study Arms (6)

Norepinephrine 3 micrograms/mL

ACTIVE COMPARATOR

1mL of a solution of norepinephrine, containing 3 micrograms/mL in normal saline, will be given intravenously to a patient if her blood pressure decreases from baseline.