Different Approaches to Maternal Hypotension During Cesarean Section

Study Overview
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Brief Summary
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The aim of this study is to compare two different therapeutic approaches to blood pressure reduction: pharmacological vs. non-pharmacological. The setting is that of patients undergoing scheduled Cesarean section under spinal anesthesia and suffering from aorta-caval compression syndrome, which causes a sudden drop in blood pressure.

Detailed Description
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The supine hypotensive syndrome of pregnancy is induced by compression of the inferior caval vein by the enlarged uterus. It occurs in approximately 8% of pregnant women at term. More patients may develop an asymptomatic variety of this syndrome in the supine position. The hypotensive effect of spinal anesthesia per se may thus be aggravated in a significant number of term parturients. A preoperative supine stress test (SST) before elective cesarean section under spinal anesthesia has been shown to predict severe systolic hypotension with reasonable accuracy. Different strategies have been proposed for the management of this complication; they can be divided into pharmacological and non-pharmacological ones. According to pharmacological strategies, vasoactive drugs are used to treat hypotension induced by sympathetic efferent blockade following spinal anesthesia. To this end, α-agonist ephedrine is commonly considered the best choice because of its minimal impact on the fetoplacental circulation. However, excessive use of ephedrine may be detrimental to neonatal well-being because of its vasoconstrictor effect on fetoplacental circulation. Non-pharmacological treatments may represent a valuable, safer alternative. According to many authors non-pharmacological treatments aimed at removing the cause of aorta-caval compression syndrome are to be preferred because more appropriate from an etiopathogenetic point of view. The use of a wedge-shaped cushion placed under the right hip is a well-known non-pharmacological strategy which allows the uterine left lateral displacement and, consequently, the removing of the compression from the inferior vena cava. The aim of the present study is to compare, through the evaluation of neonatal well-being, the efficacy of these approaches to hypotension after spinal anesthesia for elective Caesarean section in parturients affected by aorto-caval compression.

Official Title
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Pharmacological or Non-Pharmacological Management of Maternal Hypotension During Elective Cesarean Section Under Subarachnoid Anesthesia: a Randomized, Controlled Trial

Conditions
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Pregnancy, Cesarean Section, Anesthesia,Spinal, Hypotension

Intervention / Treatment
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* Drug: Bupivacaine
* Drug: Morphine
* Drug: Lactated Ringer's solution
* Drug: Ephedrine, continuous infusion
* Drug: Ephedrine, bolus
* Drug: Atropine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients undergoing spinal anesthesia for elective Cesarean section Patients in ASA Physical Status Class I or II Informed written consent to participation Positive Supine Stress Test Exclusion Criteria: Any known fetal pathology Indication to general anesthesia Known allergy to any of the study drugs

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 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: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Pharmacological<br>Patients in this group will receive a basal infusion of ephedrine. Hypotension will be treated for a reduction in systolic blood pressure 20% below baseline values. | Drug: Bupivacaine<br>* 10 mg of a 5 mg/ml hyperbaric solution, intrathecally<br>* Other names: Local Anesthetic;Drug: Morphine<br>* 200 µg of a 100 µg/ml solution, intrathecally<br>* Other names: Intrathecal morphine;Drug: Lactated Ringer's solution<br>* 25 ml/min intravenously<br>Drug: Ephedrine, continuous infusion<br>* 37.5 mg/h intravenously<br>Drug: Ephedrine, bolus<br>* 6.25 mg IV bolus prn. Hypotension defined according to study protocol for each arm.<br>Drug: Atropine<br>* 0.1 mg/kg iv bolus prn Bradycardia defined as 50% drop in heart rate from baseline values.<br>|
| Experimental: Non-Pharmacological<br>Patients in this group will undergo uterine lateral displacement through the use of a wedge-shaped cushion placed under their right hip. Hypotension will be treated for a reduction in systolic blood pressure 40% below baseline values. | Drug: Bupivacaine<br>* 10 mg of a 5 mg/ml hyperbaric solution, intrathecally<br>* Other names: Local Anesthetic;Drug: Morphine<br>* 200 µg of a 100 µg/ml solution, intrathecally<br>* Other names: Intrathecal morphine;Drug: Lactated Ringer's solution<br>* 25 ml/min intravenously<br>Drug: Ephedrine, bolus<br>* 6.25 mg IV bolus prn. Hypotension defined according to study protocol for each arm.<br>Drug: Atropine<br>* 0.1 mg/kg iv bolus prn Bradycardia defined as 50% drop in heart rate from baseline values.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Neonatal arterial base excess |  | <5 min from birth | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Neonatal arterial and venous pH, venous base excess |  | <5 min from birth | 
| Apgar score |  | 1 and 5 minutes from birth | 
| Maternal serum levels of cardiac troponin (baseline, immediate postsurgery, 6 and 12 hours after surgery) |  | Baseline and up to 12 h postoperatively | 
| Incidence of maternal hypotension ( <20% baseline or mean arterial pressure <60 mmHg). |  | q5min from anesthesia to end of surgery | 
| Incidence of maternal bradycardia (heart rate <30% of baseline or <60 beats per minute) |  | q5min from anesthesia to end of surgery | 
| Peripheral arterial oxygen saturation: incidence of desaturation (SpO2 <92%) and mean values for each arm. |  | q5min from anesthesia to end of surgery | 
| Administered atropine |  | from anesthesia to end of surgery | 
| Amount of ephedrine administered (mg) |  | from anesthesia to end of surgery | 
| Time between induction of anesthesia and skin incision |  |  | 
| Time between skin incision and delivery |  |  | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Ephedrine, Adrenergic Agents, Central Nervous System Stimulants, Sympathomimetics, Vasoconstrictor Agents, Bupivacaine, Anesthetics, Local, Atropine, Adjuvants, Anesthesia, Anti-Arrhythmia Agents, Bronchodilator Agents, Muscarinic Antagonists, Mydriatics, Parasympatholytics, Morphine, Analgesics, Opioid, Narcotics, Ringer's Lactate, Isotonic Solutions, Hypotension, Blood pressure, Signs and Symptoms, Pregnancy, Anesthesia, Obstetrical, Inferior Vena Cava