Up-Down Determination of the ED90 of Metaraminol to Treat Hypotension During Cesarean Section

Study Overview
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Brief Summary
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The purpose of this study is to find the best dose of metaraminol to be used in patients during elective cesarean sections.

Detailed Description
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The purpose of this study is to determine the effective dose 90% (ED90) of metaraminol to treat hypotension after spinal anesthesia in elective cesarean sections (CS). It is a double-blind study that uses the biased-coin up-down sequential allocation method to determine the ED90 of metaraminol. Baseline systolic blood pressure (SBP) will be determined by three automated measures 3 minutes apart just before CS. During the period from induction of spinal anesthesia to fetal delivery SBP will be monitored every minute and metaraminol will be administered every time it is lower than baseline value. If SBP falls below 80% of baseline value, the treatment will be considered a failure. An adequate response will be defined as the absence of hypotension during the study period.

Official Title
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Up-Down Determination of the ED90 of Metaraminol to Treat Hypotension During Elective Cesarean Section

Conditions
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Hypotension

Intervention / Treatment
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* Drug: Metaraminol


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Elective CS under spinal anesthesia Normal singleton pregnancy beyond 36 weeks gestation ASA physical status I/II Age over 18 years Exclusion Criteria: Patient refusal Allergy to metaraminol Preexisting or pregnancy-induced hypertension Cardiovascular or cerebrovascular disease Fetal abnormalities

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Single Group Assignment
Masking: Triple


Arms and Interventions

| Intervention/Treatment |
| --- |
|Drug: Metaraminol|Patients will be given metaraminol every time SBP falls below baseline value.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The ED90 of Metaraminol to treat hypotension in elective cesarean section will be determined. | Bolus doses of metaraminol will be used every time SBP falls below baseline values and maternal responses to doses will be used to build a dose response curve from where ED90 will be estimated. | From spinal induction until delivery (on average 30-60min) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Maternal Demographics (Age, Height, Weight and Gestational Age) |  |  | 
| Incidence of Nausea and Vomiting |  | From spinal induction until delivery (on average 30-60min) | 
| Time between skin incision and delivery |  |  | 
| Time between uterine incision and delivery |  |  | 
| Total dose of metaraminol |  |  | 
| Number of Participants with Hypertension or Bradycardia as a Measure of Safety and Tolerability |  | From spinal induction until delivery (on average 30-60min) | 
| Umbilical blood gases |  |  | 
| Fetal well-being with Apgar scores |  |  | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Cesarean section, Hypotension, Metaraminol, Vasoconstrictor Agents, Adult, Female, Pregnancy, Anesthesia, Obstetrical/adverse effects, Anesthesia,Spinal, Blood Pressure/drug effects, Nausea, Vomiting