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

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

80

Phase

  • Phase 4

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

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

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
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

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

This is where you will find people and organizations involved with this study.

Sponsor

American University of Beirut Medical Center

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

July 1, 2012

Primary Completion (Actual)

January 1, 2013

Study Completion (Actual)

January 1, 2013

Study Registration Dates

First Submitted

June 10, 2011

First Submitted That Met QC Criteria

June 21, 2011

First Posted (Estimate)

June 22, 2011

Study Record Updates

Last Update Posted (Estimate)

August 26, 2014

Last Update Submitted That Met QC Criteria

August 11, 2014

Last Verified

August 1, 2014

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • ANES.SS.10

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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