Ideal Dose of Phenylephrine to Treat Low Blood Pressure During Cesarean Section
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ClinicalTrials.gov Identifier: NCT00379691 |
Recruitment Status
:
Completed
First Posted
: September 22, 2006
Last Update Posted
: March 21, 2007
|
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Condition or disease | Intervention/treatment | Phase |
---|---|---|
Hypotension Nausea | Drug: phenylephrine | Not Applicable |
The purpose of this study is to determine the minimum effective bolus dose of phenylephrine to prevent post-spinal hypotension in CS in 95 % of our patients. The study will be conducted in a randomized double-blinded fashion. This dose-response study will be conducted as per the up-down sequential allocation method, modified by the Narayana rule, designed to cluster the results around the ED95.
Blood pressure will be monitored every minute from intrathecal injection to the delivery of the child. Phenylephrine will be administered every time the blood pressure is equal to or lower than the control value.Hypotension will be defined as a SBP less than 80 % of the baseline value, in which case the treatment will be a failure. Hypertension will be defined as a SBP more than 120 % of baseline value. If a patient presents hypertension for two consecutive measurements, the case will be considered a drop out.An adequate response will be defined as the absence of hypotension or nausea/vomiting during the period from induction of spinal anesthesia to uterine incision prior to fetal delivery.
The results of this study will define the minimum effective dose of phenylephrine to prevent post-spinal hypotension and nausea/vomiting secondary to hypotension in Cesarean section, thus optimizing the safety profile with respect to maternal and fetal side effects of this vasopressor.
Study Type : | Interventional (Clinical Trial) |
Enrollment : | 50 participants |
Allocation: | Randomized |
Intervention Model: | Single Group Assignment |
Masking: | Double |
Primary Purpose: | Prevention |
Official Title: | Phenylephrine Dose-Finding Study to Minimize Hypotension Due to Spinal Anesthesia for Cesarean Section |
Study Start Date : | August 2006 |
Actual Study Completion Date : | December 2006 |

- The primary outcome will be the minimum dose of phenylephrine which effectively prevents both hypotension and nausea/vomiting between intrathecal injection of the local anesthetic and delivery of the fetus.
- Maternal Demographics: Maternal age-weight-height
- Nausea and Vomiting
- Time of intrathecal injection, skin incision, uterine incision, and delivery
- Total dose of phenylephrine
- Hypertension (> 120 % of baseline)
- Bradycardia (< 50 bpm)
- Upper sensory level of anesthesia by pinprick upon delivery
- Umbilical artery and vein blood gases

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Ages Eligible for Study: | 18 Years and older (Adult, Senior) |
Sexes Eligible for Study: | Female |
Accepts Healthy Volunteers: | Yes |
Inclusion Criteria:
- Elective CS under spinal anesthesia
- Normal singleton pregnancy beyond 36 weeks gestation
- ASA physical status I/II
- Weight 50-100 kg, height 150-180 cm
- Age over 18 years
Exclusion Criteria:
- Patient refusal
- Allergy or hypersensitivity to phenylephrine
- Preexisting or pregnancy-induced hypertension
- Cardiovascular or cerebrovascular disease
- Fetal abnormalities
- History of diabetes, excluding gestational diabetes

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): NCT00379691
Canada, Ontario | |
Mount Sinai Hospital | |
Toronto, Ontario, Canada, M5G 1X5 |
Principal Investigator: | Jose CA Carvalho, MD PhD | Department of Anesthesia and Pain Management, Mount Sinai Hospital, University of Toronto |
ClinicalTrials.gov Identifier: | NCT00379691 History of Changes |
Other Study ID Numbers: |
06-01 06-0186-E |
First Posted: | September 22, 2006 Key Record Dates |
Last Update Posted: | March 21, 2007 |
Last Verified: | March 2007 |
Keywords provided by Samuel Lunenfeld Research Institute, Mount Sinai Hospital:
spinal Cesarean section hypotension |
nausea vomiting phenylephrine |
Additional relevant MeSH terms:
Nausea Hypotension Signs and Symptoms, Digestive Signs and Symptoms Vascular Diseases Cardiovascular Diseases Phenylephrine Oxymetazoline 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 |