Up-Down Determination of the ED90 of Phenylephrine for Hypotension Prophylaxis in Cesarean Delivery

This study has been terminated.
(Results Invalid, study closed, analysis cannot proceed.)
Sponsor:
Information provided by (Responsible Party):
Ronald George, IWK Health Centre
ClinicalTrials.gov Identifier:
NCT00796328
First received: November 19, 2008
Last updated: September 3, 2014
Last verified: September 2014

November 19, 2008
September 3, 2014
November 2008
February 2009   (final data collection date for primary outcome measure)
Effective Dose of Phenylephrine at Which 90% of Subjects Have no Spinal Induced Hypotension [ Time Frame: Spinal administration until delivery ] [ Designated as safety issue: No ]
The effective dose at which 90% of subjects will have a "positive" response to a phenylephrine infusion, i.e. no spinal induced hypotension. We hypothesize that the ED90 will be between 40 - 60 mcg/min.
The ED90 of phenylephrine infused intravenously from the time the spinal is administered until delivery to prevent the subjects systolic blood pressure from decreasing by 20% or below an absolute value (90 mmHg) [ Time Frame: Spinal administration until delivery ] [ Designated as safety issue: No ]
Complete list of historical versions of study NCT00796328 on ClinicalTrials.gov Archive Site
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Up-Down Determination of the ED90 of Phenylephrine for Hypotension Prophylaxis in Cesarean Delivery
Up-down Determination of the ED90 of the Initial Rate of Infusion of Phenylephrine for the Prophylaxis of Spinal Induced Hypotension in Parturients Undergoing Cesarean Delivery

This study is designed to determine the ED90 for an infusion of phenylephrine to prevent spinal induced low blood pressure in parturients presenting for an elective cesarean delivery. The up-down methodology (UDM) is commonly used study method to determine the dose of a drug that causes the desired effect in over 90% of the subjects to whom it given. For example: the investigators want to know what is the best dose of phenylephrine (from a range of commonly used doses) to prevent a drop in blood pressure during cesarean delivery ninety times out of one hundred when it is given at that dose. The ED90 is the effective dose at which 90% of subjects will have a "positive" response to a phenylephrine infusion, i.e. no drop in blood pressure. The investigators hypothesize that the ED90 will be between 40 - 60 mcg/min.

The primary outcome measure is the ED90 for phenylephrine infusions that prevents a drop in blood pressure in women undergoing cesarean delivery.

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Interventional
Phase 4
Endpoint Classification: Efficacy Study
Intervention Model: Single Group Assignment
Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor)
Primary Purpose: Prevention
Spinal Induced Hypotension in Cesarean Delivery
Drug: Phenylephrine infusion
Up-down, biased coin design
Experimental: 1
Intervention: Drug: Phenylephrine infusion
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*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Terminated
45
July 2009
February 2009   (final data collection date for primary outcome measure)

Inclusion Criteria:

  1. Non-emergent cesarean delivery with planned spinal anesthesia (i.e. elective planned cesarean delivery for malposition, patient choice, cervical pelvic disproportion, previous cesarean delivery and other diagnosis that require a predetermined cesarean delivery)
  2. American Society of Anesthesia physical status class I & II (ASA I - Healthy, ASA II - mild and controlled systemic disease, eg. controlled essential hypertension)
  3. Age ≥ 18 years (Standard within the obstetrical literature)
  4. Term gestational age
  5. English-speaking

Exclusion Criteria:

  1. Morbid Obesity (Body Mass Index ≥ 45 kg/m2) (Morbidly obese parturients require a dose of local anesthetic less than the standardized dose in this study, typically have an exaggerated response to vasopressors, and the blood pressure cuff occasionally needs to be replaced by an intra-arterial catheter due to limitations in size)
  2. Height < 5'0" (Women < 5'0" are likely to require a dose of local anesthetic less than the standardized dose in this study)
  3. Laboring women
  4. Urgent or emergency cesarean delivery
  5. Hypertensive disease of pregnancy
  6. Severe maternal cardiac disease
  7. Subjects on monoamine oxidase inhibitors (MAOI's) or tricyclic antidepressants
  8. Fetal anomalies or intrauterine fetal death
  9. Failed spinal anesthesia
  10. Subject enrollment in another study involving a study medication within 30 days of CD
  11. Any other physical or psychiatric condition which may impair their ability to cooperate with study data collection
Female
18 Years and older
Yes
Contact information is only displayed when the study is recruiting subjects
Not Provided
 
NCT00796328
IWK-4462-2008
Yes
Ronald George, IWK Health Centre
IWK Health Centre
Not Provided
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IWK Health Centre
September 2014

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP