Variable Rate Phenylephrine Infusion for Prevention of Spinal-induced Hypotension for Cesarean Delivery

August 11, 2014 updated by: Sahar Sayyid, American University of Beirut Medical Center

Crystalloid Coload Combined With Variable Rate Phenylephrine Infusion for Prevention of Hypotension During Spinal Anesthesia for Elective Cesarean Delivery vs Crystalloid Coload Alone

Rapid administration of crystalloid immediately after induction of spinal anesthesia (coload) to be more effective in terms of managing hypotension as compared to administering crystalloid before spinal anesthesia (preload).

Phenylehrine infusion is a safe and effective way to reduce incidence and frequency of hypotension during SA for cesarean delivery. Hypotension was virtually eliminated by use of high-dose prophylactic phenylephrine infusion at a rate of 100 µg/min and rapid crystalloid coload up to two liters (administration at the time of SA). However, incidence of reactive hypertension was frequent up to 47% with decrease in maternal heart rate (HR). This may raise concern in patients in whom increase of blood pressure may be detrimental, like chronic hypertension and in the presence of a compromised uteroplacental blood flow. A recent study found that infusing phenylephrine at a fixed rate of 75 and 100 ug/min is associated with more episodes of hypertension than placebo or the lower infusion rates of 25 and 50 ug/min respectively. However, there was no reduction in the number of physician interventions (phenylephrine boluses and stopping the infusion) needed to maintain maternal systolic blood pressure within 20% of baseline among all groups. Prophylactic fixed rate infusions may have limited application in clinical practice, and a variable rate (i.e. modifying the rate according to hemodynamics) has been advocated. The bolus administration of phenylephrine to treat hypotension is still commonly used, but requests multiple interventions from the anesthesiologists and is time consuming.

Eighty patients scheduled for cesarean delivery under spinal anesthesia will be assigned to one of two groups. Immediately after spinal injection, rapid crystalloid colaod of lactated Ringer of 15 mL/kg over a period of 10-15 min will be initiated. Patients in Group I will receive infusion of normal saline (placebo) and patients in group II variable infusion rate of phenylephrine started at 0.75 ug/kg (close to the dose of 50 ug/min recommended for fixed infusion rate). The number of interventions needed to maintain maternal systolic blood pressure within 20% of baseline, hemodynamic performance, intraoperative nausea and vomiting, and umbilical cord blood gases will be compared between the two groups.

We will define a reliable and safe method to ensure maternal hemodynamic stability during spinal anesthesia for cesarean delivery with the least physician interference.

Study Overview

Status

Status

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Completed

Conditions

Conditions

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Intervention / Treatment

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Study Type

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Interventional

Enrollment (Actual)

Enrollment

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80

Phase

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  • Phase 4

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Eligibility Criteria

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Ages Eligible for Study

18 years to 50 years (Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

Female

Description

Inclusion Criteria:

  • Parturients beyond 37 weeks gestation
  • ASA І or ІІ

Exclusion Criteria:

  • pregnancy-induced hypertension
  • chronic hypertension
  • multiple pregnancy
  • fetal compromise
  • diabetes mellitus
  • polyhydramnios
  • body weight >100 kg
  • major systemic disease
  • anemia (hemoglobin concentration<10 g/dl)
  • clotting diathesis

Study Plan

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How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

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Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Phenylephrine
PHenylephrine infusion started at 0.75 microgram per kg per mL started at spinal injection till delivery
Drug: Phenylephrine
Prophylactic variable rate of phenylephrine infusion started at 0.75 µg/kg/min vs saline
Other Names:
  • Neosynephrine
Placebo Comparator: Saline
Prophylactic variable rate of saline infusion where we adjusted the pump at a starting rate of 0.75 µg/kg/min, equivalent to 0.0075 mL/kg/min of saline
Drug: saline
Prophylactic variable rate of saline infusion where we adjusted the pump at a starting rate of 0.75 µg/kg/min, equivalent to 0.0075 mL/kg/min of saline

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Number of Physician Interventions Needed to Maintain Maternal Blood Pressure After Spinal Anesthesia Within 20% of Baseline and to Treat Bradycardia During Cesarean Delivery.
Time Frame: Patients will be followed up throughout the Cesarean delivery (average of 1.5 hours).

Physician interventions are triggered by hemodynamic changes more than 20% of baseline. The intervention can be one or more of the following:

  • stopping the phenylephrine infusion
  • changing the rate of phenylephrine infusion
  • rescue intravenous bolus of phenylephrine (100 µg) for hypotension
  • rescue intravenous bolus of atropine (0.4 mg) for bradycardia
Patients will be followed up throughout the Cesarean delivery (average of 1.5 hours).

Collaborators and Investigators

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Sponsor

Sponsor

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American University of Beirut Medical Center

Study record dates

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Study Major Dates

Study Start

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 1, 2012

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
January 1, 2013

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
January 1, 2013

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
June 10, 2011

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 21, 2011

First Posted (Estimate)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 22, 2011

Study Record Updates

Last Update Posted (Estimate)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
August 26, 2014

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 11, 2014

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2014

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

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  • ANES.SS.10

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