Norepinephrine and Phenylephrine for Maternal Cardiac Output During Spinal Anesthesia for Elective Cesarean Delivery

Study Overview
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Brief Summary
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The purpose of this study is to compare norepinephrine and phenylephrine on the effects of maintaining the cardiac output in Cesarean section under spinal anesthesia.

Detailed Description
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CO was measured using the NICOM® monitor. Bioreactance, a development from impedance technology, is also emerging as an accessible mode of continuous CO monitoring in the operating room and can provide valuable insight into the hemodynamic effects of our interventions. This method of monitoring provides continuous CO, stroke volume (SV) and heart rate (HR) monitoring, and intermittent BP and SVR assessments at 1-minute intervals. Either phenylephrine (100 mcg/ml) or norepinephrine (0.5 mcg/ml) in 50-ml syringe that were labeled study drug. She was not involved in patient's care or study assessment. The hypotension was defined as systolic blood pressure <80% of baseline or < 90 mmHg, and managed with study drug (1 ml) intravenously. The bradycardia was defined as HR < 60 beats/min and was recorded and managed with atropine (0.5 mg) intravenously as HR < 45 beats/min. The presence of nausea and vomiting was measured on a 3 point scale (1 = no nausea and vomiting, 2 = nausea only, and 3 = both nausea and vomiting) and managed with ondansetron (4mg) intravenously.

Official Title
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Norepinephrine and Phenylephrine for Cesarean Section

Conditions
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Hypotension

Intervention / Treatment
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* Drug: Norepinephrine
* Drug: Phenylephrine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ASA class I and II, term pregnancy (gestational age>37weeks), planned spinal anesthesia for elective cesarean section Exclusion Criteria: preexisting or gestational hypertension, cerebrovascular or cardiovascular disease, any contraindication to the spinal anesthesia, fetal anormaly, weight<50kg or >100kg, and height<140cm or >180cm.

Ages Eligible for Study
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Minimum Age: 19 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: norepinephrine<br>norepinephrine 5mcg intravenously administered | Drug: Norepinephrine<br>* bolus administered norepinephrine 5mcg intravenously, if SBP <90mmHg or 20% decrease from baseline<br>* Other names: vasopressor given;|
| Active Comparator: phenylephrine<br>phenylephrine 100mcg intravenously administered | Drug: Phenylephrine<br>* bolus administered phenylephrine 100mcg intravenously, if SBP <90mmHg or 20% decrease from baseline<br>* Other names: vasopressor given;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| change of cardiac index (L/min/m2) | Change from Baseline at time 2, 3, 4, and 5 | 1. initial (baseline); 2. 20 min after spinal anesthesia; 3. 1min after the surgery; 4. 1min after baby out; 5. 1min after the end of surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| change of Stroke volume (ml/beat) | Change from Baseline at time 2, 3, 4, and 5 | 1. initial (baseline); 2. 20 min after spinal anesthesia; 3. 1min after the surgery; 4. 1min after baby out; 5. 1min after the end of surgery | 
| change of Total Peripheral Resistance (dynes sec/cm3) | Change from Baseline at time 2, 3, 4, and 5 | 1. initial (baseline); 2. 20 min after spinal anesthesia; 3. 1min after the surgery; 4. 1min after baby out; 5. 1min after the end of surgery | 
| change of Systolic blood pressure (mmHg) | Change from Baseline at time 2, 3, 4, and 5 | 1. initial (baseline); 2. 20 min after spinal anesthesia; 3. begin the surgery; 4. baby out; 5. the end of surgery | 
| change of heart rate (beats per minute) | Change from Baseline at time 2, 3, 4, and 5 | 1. initial (baseline); 2. 20 min after spinal anesthesia; 3. 1min after the surgery; 4. 1min after baby out; 5. 1min after the end of surgery |