Effect of Different Left Lateral Table Tilt for Elective Cesarean Delivery Under Spinal Anesthesia

Study Overview
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Brief Summary
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The recommended position of the mother under caesarean section after spinal anesthesia is 15 degrees left. However, recent research has challenged the basic principles and practicality of the left-turn 15 degree position. Higuchi et al used nuclear magnetic imaging to directly prove that in the supine position, the position of the full-left 30 degrees of the full-term pregnancy of the full-term pregnancy relieved the inferior vena cava compression and the left-angle of 15 degrees did not. Therefore, there are more and more controversies about the choice of cesarean section position. This experiment aims to explore effects of different positions (15 degrees left, 30 degrees left and supine) for elective cesarean section on lumbar anesthesia for fetal acid-base balance and maternal Hemodynamic.

Detailed Description
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When the pregnant woman in the third trimester is in the supine position, the enlarged uterus may oppress the inferior vena cava, thereby reducing the amount of blood and heart output of the pregnant woman. This affects the mother mainly, such as dizziness, nausea and vomiting, chills, and severe irritability，difficulty breathing or even cardiac arrest, the impact on the fetus is mainly the reduction of blood flow in the placenta, affecting the blood exchange of the uterus placenta, causing neonatal respiratory distress, acidosis and even death. The recommended position of the mother under caesarean section after spinal anesthesia is 15 degrees left. However, recent research has challenged the basic principles and practicality of the left-turn 15 degree position. Higuchi et al used nuclear magnetic imaging to directly prove that in the supine position, the position of the full-left 30 degrees of the full-term pregnancy of the full-term pregnancy relieved the inferior vena cava compression and the left-angle of 15 degrees did not. Therefore, there are more and more controversies about the choice of cesarean section position. This experiment aims to explore effects of different positions (15 degrees left, 30 degrees left and supine) for elective cesarean section on lumbar anesthesia for fetal acid-base balance and maternal Hemodynamic.

Official Title
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Effect of Different Left Lateral Table Tilt on Neonatal Acid-base Status and Maternal Hemodynamics for Elective Cesarean Delivery Under Spinal Anesthesia

Conditions
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Elective Cesarean Section, Spinal Anesthesia

Intervention / Treatment
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* Device: 15° and 30° wedge sponges


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Singleton pregnancy at term via elective cesarean section Height from 150 cm to 180 cm American Society of Anesthesiologists (ASA) grade from I to II grade BMI（Body Mass Index，mearsured weight divided by height squared）less than 35 kg/m2. Exclusion Criteria: Transverse lie Fetal macrosomia Uterine abnormalities (e.g., large fibroids, bicornuate uterus) Polyhydramnios Ruptured membranes Oligohydramnios Intrauterine growth restriction Gestational or nongestational hypertension, diabetes, eclampsia Hypertensive disorder or any condition associated with autonomic neuropathy (e.g., diabetes mellitus for more than 10 yr), with renal failure Have contraindications for spinal anesthesia（Such as low back infection, spinal deformity, etc.） Participants refused to sign informed consent.

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: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Supine group<br>After the patient completes the spinal anesthesia, the cesarean section is completed in the supine position. | Device: 15° and 30° wedge sponges<br>* After the spinal anesthesia is completed, the wedge sponge is placed between the patient's pelvis and ribs and the wedge is removed before the skin is cut.<br>|
| Active Comparator: 15° group<br>After the patient completed the spinal anesthesia, the preoperative preparation (about 10 minutes) was completed with a left tilt of 15°, and the cesarean section was completed using the supine position after the skin was cut. | Device: 15° and 30° wedge sponges<br>* After the spinal anesthesia is completed, the wedge sponge is placed between the patient's pelvis and ribs and the wedge is removed before the skin is cut.<br>|
| Active Comparator: 30° group<br>After the patient completed the spinal anesthesia, the preoperative preparation (about 10 minutes) was completed with a left tilt of 30°, and the cesarean section was completed using the supine position after the skin was cut. | Device: 15° and 30° wedge sponges<br>* After the spinal anesthesia is completed, the wedge sponge is placed between the patient's pelvis and ribs and the wedge is removed before the skin is cut.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Umbilical artery blood pH | Use a blood gas analyzer to measure | Immediately after delivery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Other UA and UV blood gas analysis values（pH, base excess, lactate , Umbilical artery blood PaCO2 | Use a blood gas analyzer to measure, PaCO2 in mmHg. | Immediately after delivery | 
| Fetal Apgar score (1 minute after birth) And 5 minutes | Measured by Apgar score.The Apgar scoring system is divided into five categories（muscle tone，heart rate，grimace and respiration) Appearance. Each category receives a score of 0 to 2 points. At most, a child will receive an overall score of 10（The higher the score, the better the child's condition）. | One minute and five minutes after the baby is delivered | 
| The incidence of nausea in pregnant women | Anesthesiologist observes combined patient dictation. | Intraoperative | 
| The incidence of vomiting in pregnant women | Anesthesiologist observes combined patient dictation | Intraoperative | 
| The incidence of hypotension in pregnant women | The increase of SBP <20% baseline SBP or SBP < 90/60mmHg | Intraoperative | 
| The incidence of hypertension in pregnant women | The increase of SBP >20% baseline SBP | Intraoperative | 
| The incidence of bradycardia in pregnant women | Heart rate less than 60 times per minute | Intraoperative | 
| One min (T1), 3 min (T2), 5 min (T3), 7 min (T4), 9 min (T5), 11 min (T6), 13 min (T7) and 15 min (T8) blood pressure after subarachnoid injection (completion of the subarachnoid injection was defined as 0 time point) | Measured by a sphygmomanometer.Systolic and diastolic blood pressure will be measured every minute during the study. | Intraoperative | 
| One min (T1), 3 min (T2), 5 min (T3), 7 min (T4), 9 min (T5), 11 min (T6), 13 min (T7) and 15 min (T8) heart rate after subarachnoid injection (completion of the subarachnoid injection was defined as 0 time point) | Obtained by ECG measurement | Intraoperative | 
| Dosage of phenylephrine during surgery | Used by an anesthesiologist based on the patient's blood pressure and heart rate.If the patient's blood pressure is less than 80% of the baseline level or less than 90/60 mmHg and the heart rate is greater than 60 times per minute, the patient is given 4 ug of phenylephrine. | Intraoperative | 
| Dosage of ephedrine during surgery | Used by an anesthesiologist based on the patient's blood pressure and heart rate.If the patient's blood pressure is less than 80% of the baseline level or less than 90/60 mmHg and the heart rate is smaller than 60 times per minute, the patient is given 6 mg of ephedrine. | Intraoperative | 
| Dosage of atropine during surgery | Used by an anesthesiologist based on the patient's blood pressure and heart rate.If the patient's heart rate is smaller than 60 times per minute, and blood pressure is more than 80% of the baseline level and more than 90/60 mmHg， the patient is given 0.5 mg of atropine. | Intraoperative | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Position