Phenylephrine in Spinal Anesthesia in Preeclamptic Patients
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ClinicalTrials.gov Identifier: NCT00458003 |
Recruitment Status :
Completed
First Posted : April 9, 2007
Results First Posted : June 2, 2022
Last Update Posted : June 2, 2022
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Hypotension remains a common clinical problem after induction of spinal anesthesia for cesarean delivery. Maternal hypotension has been associated with considerable morbidity (maternal nausea and vomiting and fetal/neonatal acidemia). Traditionally, ephedrine has been the vasopressor of choice because of concerns about phenylephrine's potential adverse effect on uterine blood flow. This practice was based on animal studies which showed that ephedrine maintained cardiac output and uterine blood flow, while direct acting vasoconstrictors, e.g., phenylephrine, decreased uteroplacental perfusion. However, several recent studies have demonstrated that phenylephrine has similar efficacy to ephedrine for preventing and treating hypotension and may be associated with a lower incidence of fetal acidosis. All of these studies have been performed in healthy patients undergoing elective cesarean delivery.
Preeclampsia complicates 5-6% of all pregnancies and is a significant contributor to maternal and fetal morbidity and mortality. Many preeclamptic patients require cesarean delivery of the infant. These patients often have uteroplacental insufficiency. Given the potential for significant hypotension after spinal anesthesia and its effect on an already compromised fetus, prevention of (relative) hypotension in preeclamptic patients is important. Spinal anesthesia in preeclamptic patients has been shown to have no adverse neonatal outcomes as compared to epidural anesthesia when hypotension is treated adequately. Due to problems related to management of the difficult airway and coagulopathy, both of which are more common in preeclamptic women, spinal anesthesia may be the preferred regional anesthesia technique. Recent studies have demonstrated that preeclamptic patients may experience less hypotension after spinal anesthesia than their healthy counterparts. To our knowledge, phenylephrine for the treatment of spinal anesthesia-induced hypotension has not been studied in women with preeclampsia. The aim of our study is to compare intravenous infusion regimens of phenylephrine versus ephedrine for the treatment of spinal anesthesia induced hypotension in preeclamptic patients undergoing cesarean delivery. The primary outcome variable is umbilical artery pH.
Condition or disease | Intervention/treatment | Phase |
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Preeclampsia Hypotension | Drug: Ephedrine Drug: Phenylephrine | Not Applicable |

Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 110 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | Double (Participant, Investigator) |
Primary Purpose: | Treatment |
Official Title: | Phenylephrine Versus Ephedrine to Treat Spinal Anesthesia-Induced Hypotension in Preeclamptic Patients During Cesarean Delivery |
Study Start Date : | July 2006 |
Actual Primary Completion Date : | December 2016 |
Actual Study Completion Date : | December 2016 |

Arm | Intervention/treatment |
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Experimental: Phenylephrine
Subject will receive a phenylephrine infusion to prevent and to treat hypotension associated with spinal anesthesia
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Drug: Phenylephrine
Phenylephrine concentration: 100 mcg/mL. The infusion will be initiated immediately after completion of the spinal injection at a rate of 1 mL/min and continued for a minimum of 2 min after which the infusion will be stopped, continued or increased based on the SBP each minute. After each SBP measurement the infusion will be stopped if SBP > 80% baseline, and the infusion will be continued or restarted if the SBP is approximately equal to 80% baseline. The infusion will be increased by 1 mL/min if the SBP < 80% baseline. Each time there is hypotension the patient will receive a 1 mL IV bolus of the study solution and the infusion will be increased by 1 mL/min until delivery. |
Active Comparator: Ephedrine
Subject will receive an ephedrine infusion to prevent and to treat hypotension associated with spinal anesthesia
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Drug: Ephedrine
Ephedrine concentration: 8 mg/mL. The infusion will be initiated immediately after completion of the spinal injection at a rate of 1 mL/min and continued for a minimum of 2 min after which the infusion will be stopped, continued or increased based on the SBP each minute. After each SBP measurement the infusion will be stopped if SBP > 80% baseline, and the infusion will be continued or restarted if the SBP is approximately equal to 80% baseline. The infusion will be increased by 1 mL/min if the SBP < 80% baseline. Each time there is hypotension the patient will receive a 1 mL IV bolus of the study solution and the infusion will be increased by 1 mL/min until delivery. |
- The Umbilical Artery pH [ Time Frame: Immediately after delivery ]
The umbilical artery blood pH immediately after delivery. The pH scale ranges from 0 to 14. A normal pH sample from the umbilical artery ranges from pH: 7.18 - 7.38.
The lower the pH the more acidic and the higher the pH the more basic.
- The Umbilical Artery Blood Base Excess [ Time Frame: Immediately after delivery ]
The umbilical artery blood base excess immediately after delivery. Base excess and base deficit refer to an excess or deficit, in the amount of base present in the blood.
The value (-2 to +2 normal range) is usually reported as a concentration in units of mEq/L, with positive numbers indicating an excess of base and negative a deficit

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Ages Eligible for Study: | 18 Years to 60 Years (Adult) |
Sexes Eligible for Study: | Female |
Accepts Healthy Volunteers: | Yes |
Inclusion Criteria:
- ASA PS II - III women
- 18 years old and older
- scheduled for cesarean delivery (no trial of labor)
- eligible for spinal anesthesia
- diagnosis of preeclampsia
Exclusion Criteria:
- patients with failed trial of labor
- preexisting hypertension
- body mass index (BMI) ≥ 40 kg/m2
- resting heart rate < 60 bpm
- progression to eclampsia, > twin gestation
- known fetal anomalies
- contraindications to spinal anesthesia
- emergency procedure or refusal of consent
- failure to achieve a T6 level of anesthesia
- conversion to general anesthesia

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00458003
United States, Illinois | |
Northwestern Memorial Hospital | |
Chicago, Illinois, United States, 60611 | |
Northwestern University | |
Chicago, Illinois, United States, 60611 |
Study Chair: | David Walega, M.D. | Northwestern University |
Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: | David Walega, Research Vice Chair Anesthesiology, Northwestern University |
ClinicalTrials.gov Identifier: | NCT00458003 |
Other Study ID Numbers: |
0524-31 |
First Posted: | April 9, 2007 Key Record Dates |
Results First Posted: | June 2, 2022 |
Last Update Posted: | June 2, 2022 |
Last Verified: | May 2022 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | No |
Preeclampsia Spinal Anesthesia Hypotension |
Cesarean Delivery Phenylephrine Ephedrine |
Pre-Eclampsia Hypotension Vascular Diseases Cardiovascular Diseases Hypertension, Pregnancy-Induced Pregnancy Complications Phenylephrine Oxymetazoline Ephedrine Cardiotonic Agents Mydriatics Autonomic Agents Peripheral Nervous System Agents |
Physiological Effects of Drugs Sympathomimetics Vasoconstrictor Agents Nasal Decongestants Respiratory System Agents Adrenergic alpha-1 Receptor Agonists Adrenergic alpha-Agonists Adrenergic Agonists Adrenergic Agents Neurotransmitter Agents Molecular Mechanisms of Pharmacological Action Protective Agents Central Nervous System Stimulants |