Comparison of Different HES Coload Volumes on the 90% ED of Norepinephrine

Study Overview
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Brief Summary
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The purpose of this study is to investigate the effect of different 6% hydroxyethyl starch (130/0.4) coload volumes on the 90% effective dose of norepinephrine infusion prophylaxis for hypotension during spinal anesthesia for cesarean section.

Detailed Description
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Post-spinal anesthesia hypotension is a frequent complication during spinal anesthesia for cesarean section. The incidence of post-spinal anesthesia hypotension is as high as 62.1-89.7% if prophylactic measures are not taken. Coload has been highly demonstrated for prevention and/or treatment of post-spinal anesthesia hypotension. In addition, there's some evidence that prophylactic infusion of norepinephrine could effectively reduce the incidence of post-spinal anesthesia hypotension in parturients undergoing cesarean section. The purpose of this study is to investigate the effect of different 6% hydroxyethyl starch (130/0.4) coload volumes on the 90% effective dose of norepinephrine infusion prophylaxis for hypotension during spinal anesthesia for cesarean section.

Official Title
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Comparison of Different 6% Hydroxyethyl Starch (130/0.4) Coload Volumes on the 90% Effective Dose of Norepinephrine Infusion Prophylaxis for Hypotension During Spinal Anesthesia for Cesarean Section

Conditions
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Adverse Effect

Intervention / Treatment
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* Drug: Hydroxyethyl starch coload - 0 ml/kg
* Drug: Hydroxyethyl starch coload - 5 ml/kg
* Drug: Hydroxyethyl starch coload - 10 ml/kg


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 18-45 years Primipara or multipara Singleton pregnancy ≥37 weeks American Society of Anesthesiologists physical status classification I to II Scheduled for cesarean section under spinal anesthesia Exclusion Criteria: Body height < 150 cm Body weight > 100 kg or body mass index (BMI) ≥ 40 kg/m2 Eclampsia or chronic hypertension or baseline blood pressure ≥180 mmHg Hemoglobin < 7g/dl Fetal distress, or known fetal developmental anomaly

Ages Eligible for Study
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Minimum Age: 18 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: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: 0 ml/kg Hydroxyethyl starch coload group<br>No fluid coload was given. An initial infusion dose of prophylactic norepinephrine simultaneous with spinal anesthesia | Drug: Hydroxyethyl starch coload - 0 ml/kg<br>* No fluid coload was given. An initial infusion dose of prophylactic norepinephrine (0.025 ug/kg/min) simultaneous with spinal anesthesia. The dose administered to subsequent patients varied by increments or decrements of 0.005 ug/kg/min of prophylactic norepinephrine according to the responses of previous patients according to the up-down sequential allocation.<br>* Other names: Colloid;|
| Experimental: 5 ml/kg Hydroxyethyl starch coload group<br>5 ml/kg 6% Hydroxyethyl starch (130/0.4) coload combined with an initial infusion dose of prophylactic norepinephrine simultaneous with spinal anesthesia. | Drug: Hydroxyethyl starch coload - 5 ml/kg<br>* 5 ml/kg 6% Hydroxyethyl starch (130/0.4) coload combined with an initial infusion dose of prophylactic norepinephrine (0.025 ug/kg/min) simultaneous with spinal anesthesia. The dose administered to subsequent patients varied by increments or decrements of 0.005 ug/kg/min of prophylactic norepinephrine according to the responses of previous patients according to the up-down sequential allocation.<br>* Other names: Colloid;|
| Experimental: 10 ml/kg Hydroxyethyl starch coload group<br>10 ml/kg 6% Hydroxyethyl starch (130/0.4) coload combined with an initial infusion dose of prophylactic norepinephrine simultaneous with spinal anesthesia. | Drug: Hydroxyethyl starch coload - 10 ml/kg<br>* 10 ml/kg 6% Hydroxyethyl starch (130/0.4) coload combined with an initial infusion dose of prophylactic norepinephrine (0.025 ug/kg/min) simultaneous with spinal anesthesia. The dose administered to subsequent patients varied by increments or decrements of 0.005 ug/kg/min of prophylactic norepinephrine according to the responses of previous patients according to the up-down sequential allocation.<br>* Other names: Colloid;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| ED 50 | The dose of prophylactic norepinephrine that would be effective in preventing postspinal anesthesia hypotension in 50% (effective dose, ED 50) of patients | 1-15 minutes after spinal anesthesia | 
| ED 90 | The dose of prophylactic norepinephrine that would be effective in preventing postspinal anesthesia hypotension in 90% (ED90) of patients | 1-15 minutes after spinal anesthesia | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The incidence of post-spinal anesthesia hypotension | Systolic blood pressure (SBP) < 80% of the baseline | 1-15 minutes after spinal anesthesia | 
| The incidence of severe post-spinal anesthesia hypotension | Systolic blood pressure (SBP) < 60% of the baseline | 1-15 minutes after spinal anesthesia | 
| The incidence of bradycardia | Heart rate < 60 beats/min | 1-15 minutes after spinal anesthesia | 
| The incidence of nausea and vomiting | Presence of nausea and vomiting in patients after spinal anesthesia | 1-15 minutes after spinal anesthesia | 
| The incidence of hypertension | Systolic blood pressure (SBP) >120% of the baseline | 1-15 minutes after spinal anesthesia | 
| pH | From umbilical arterial blood gases | Immediately after delivery | 
| Partial pressure of oxygen (PO2) | From umbilical arterial blood gases | Immediately after delivery | 
| Base excess (BE) | From umbilical arterial blood gases | Immediately after delivery | 
| APGAR score | A= Appearance P=Pulse G=Grimace A=Attitude R=Respiration | 1 min after delivery | 
| APGAR score | A= Appearance P=Pulse G=Grimace A=Attitude R=Respiration | 5 min after delivery | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Coload, Norepinephrine, Hydroxyethyl starch 130/0.4, Postspinal anesthesia hypotension, Cesarean section