Preventive Intramuscular Phenylephrine in Elective Cesarean Section Under Spinal Anesthesia

Study Overview
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Brief Summary
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Spinal anesthesia is the preferred anesthesia method in cesarean section to provide satisfactory analgesia and muscle relaxant with less impact on respiratory system. However, hypotension often occurred due to the block of sympathetic nerve, causing maternal decline of frontal lobe oxygenation, nausea vomit and the decrease of uteroplacental perfusion. Several measures are used to prevent or treat hypotension caused by spinal anesthesia: prehydration, limb compression, left lateral tilt of operation tables or usage of vasopressors. In the past decade, the most recommended vasopressor to prevent or treat hypotension in spinal anesthesia in cesarean section was phenylephrine, an α-adrenergic receptor, maintaining maternal blood pressure and fetal acid-base state. In clinical work, there are two ways to use phenylephrine : intravenous method with less onset time (several seconds and duration (several minutes) and intramuscular method with longer onset time (10-15 minutes) and duration (1 hour). Many trials demonstrated the protective effect of preventive intravenous phenylephrine on maternal hemodynamics and neonatal acid-base status. However, few trials reported the effect of preventive intramuscular phenylephrine on cesarean section under spinal anesthesia.

Detailed Description
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Hypotension often occurred in parturients undergoing cesarean section in spinal anesthesia. This study aims to determine whether preventive intramuscular phenylephrine can better the fetal acid-base state and maternal hemodynamics.

Official Title
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Preventive Intramuscular Phenylephrine in Elective Cesarean Section Under Spinal Anesthesia: A Randomized Controlled Tiral

Conditions
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Elective Cesarean Section, Spinal Anesthesia

Intervention / Treatment
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* Drug: Phenylephrine
* Drug: Normal saline
* Drug: Bupivacaine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 18 years to 40 years. Elective cesarean section American Society of Anesthesiologists (ASA) grade from I to Ⅱ, height from 150 cm to 180 cm, BMI<40kg/m2 Singleton pregnancy Without pregnancy complications Exclusion Criteria: Multiple pregnancy Preoperative bradycardia Coagulation dysfunction Parturients with hypertension, diabetes, eclampsia and other pregnancy complications.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 40 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: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Intramuscular phenylephrine group<br>Patients in intramuscular phenylephrine group will receive spinal anesthesia with bupivacaine. 5 mg (1ml) phenylephrine intramuscular injection will be given into the gluteus maximus muscle before anesthesia.1ml of 0.9% normal saline intravenous injection will be given after the subarachnoid injection is completed. | Drug: Phenylephrine<br>* 5 mg (1ml) phenylephrine intramuscular injection will be given into the gluteus maximus muscle before anesthesia.100ug (1ml) phenylephrine intravenous injection will be given after the subarachnoid injection is completed .<br>* Other names: Metasympatol;Drug: Normal saline<br>* 1ml 0.9% normal saline intramuscular injection will be given into the gluteus maximus muscle before anesthesia and after the subarachnoid injection is completed.<br>* Other names: Physiological saline;Drug: Bupivacaine<br>* All patients will receive spinal anesthesia with bupivacaine.<br>* Other names: Marcaine;|
| Active Comparator: Intravenous phenylephrine group<br>Patients in intravenous phenylephrine group will receive spinal anesthesia with bupivacaine. 1ml of 0.9% normal saline intramuscular injection will be given into the gluteus maximus muscle before anesthesia.100ug (1ml) phenylephrine intravenous injection will be given after the subarachnoid injection is completed. | Drug: Phenylephrine<br>* 5 mg (1ml) phenylephrine intramuscular injection will be given into the gluteus maximus muscle before anesthesia.100ug (1ml) phenylephrine intravenous injection will be given after the subarachnoid injection is completed .<br>* Other names: Metasympatol;Drug: Normal saline<br>* 1ml 0.9% normal saline intramuscular injection will be given into the gluteus maximus muscle before anesthesia and after the subarachnoid injection is completed.<br>* Other names: Physiological saline;Drug: Bupivacaine<br>* All patients will receive spinal anesthesia with bupivacaine.<br>* Other names: Marcaine;|
| Placebo Comparator: Placebo group<br>Patients in intravenous phenylephrine group will receive spinal anesthesia with bupivacaine. 1ml of 0.9% normal saline intramuscular injection will be given into the gluteus maximus muscle before anesthesia. 1ml of 0.9% normal saline intravenous injection will be given after the subarachnoid injection is completed. | Drug: Phenylephrine<br>* 5 mg (1ml) phenylephrine intramuscular injection will be given into the gluteus maximus muscle before anesthesia.100ug (1ml) phenylephrine intravenous injection will be given after the subarachnoid injection is completed .<br>* Other names: Metasympatol;Drug: Normal saline<br>* 1ml 0.9% normal saline intramuscular injection will be given into the gluteus maximus muscle before anesthesia and after the subarachnoid injection is completed.<br>* Other names: Physiological saline;Drug: Bupivacaine<br>* All patients will receive spinal anesthesia with bupivacaine.<br>* Other names: Marcaine;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Umbilical artery potential of hydrogen (pH) | detected by a blood gase analyzer | after the baby is delivered | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Umbilical venous potential of hydrogen (pH) | detected by a blood gase analyzer | after the baby is delivered | 
| Umbilical artery base excess | detected by a blood gase analyzer | after the baby is delivered | 
| Umbilical venous base excess | detected by a blood gase analyzer | after the baby is delivered | 
| Umbilical artery partial pressure of oxygen (PaO2) | detected by a blood gase analyzer | after the baby is delivered | 
| Umbilical venous partial pressure of oxygen (PaO2) | detected by a blood gase analyzer | after the baby is delivered | 
| Umbilical artery partial pressure of carbon dioxide (PaCO2) | detected by a blood gase analyzer | after the baby is delivered | 
| Umbilical venous partial pressure of carbon dioxide (PaCO2) | detected by a blood gase analyzer | after the baby is delivered | 
| Umbilical artery lactate | detected by a blood gase analyzer | after the baby is delivered | 
| Umbilical venous lactate | detected by a blood gase analyzer | after the baby is delivered | 
| Umbilical artery glucose | detected by a blood gase analyzer | after the baby is delivered | 
| Umbilical venous glucose | detected by a blood gase analyzer | after the baby is delivered | 
| Incidence of fetal acidosis | Umbilical artery pH value<7.20 | after the baby is delivered | 
| Incidence of hypotension | decrease of systolic blood pressure>20% baseline values | intraoperative | 
| Incidence of hypertension | increase of systolic blood pressure>20% baseline values | intraoperative | 
| Incidence of bradycardia | heart rate <50 bpm | intraoperative | 
| Incidence of nausea or vomit | observed by the anesthesiologist | intraoperative | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Intramuscular, Phenylephrine