Elective Cesarean Section, Spinal Anesthesia
Conditions
Keywords
Intramuscular, Phenylephrine
Brief summary
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
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.
Interventions
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 .
1ml 0.9% normal saline intramuscular injection will be given into the gluteus maximus muscle before anesthesia and after the subarachnoid injection is completed.
All patients will receive spinal anesthesia with bupivacaine.
Sponsors
Study design
Eligibility
Inclusion criteria
1. Age 18 years to 40 years. 2. Elective cesarean section 3. American Society of Anesthesiologists (ASA) grade from I to Ⅱ, height from 150 cm to 180 cm, BMI\<40kg/m2 4. Singleton pregnancy 5. Without pregnancy complications
Exclusion criteria
1. Multiple pregnancy 2. Preoperative bradycardia 3. Coagulation dysfunction 4. Parturients with hypertension, diabetes, eclampsia and other pregnancy complications.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Umbilical artery potential of hydrogen (pH) | after the baby is delivered | detected by a blood gase analyzer |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Umbilical artery base excess | after the baby is delivered | detected by a blood gase analyzer |
| Umbilical venous base excess | after the baby is delivered | detected by a blood gase analyzer |
| Umbilical artery partial pressure of oxygen (PaO2) | after the baby is delivered | detected by a blood gase analyzer |
| Umbilical venous partial pressure of oxygen (PaO2) | after the baby is delivered | detected by a blood gase analyzer |
| Umbilical artery partial pressure of carbon dioxide (PaCO2) | after the baby is delivered | detected by a blood gase analyzer |
| Umbilical venous partial pressure of carbon dioxide (PaCO2) | after the baby is delivered | detected by a blood gase analyzer |
| Umbilical artery lactate | after the baby is delivered | detected by a blood gase analyzer |
| Umbilical venous potential of hydrogen (pH) | after the baby is delivered | detected by a blood gase analyzer |
| Umbilical artery glucose | after the baby is delivered | detected by a blood gase analyzer |
| Umbilical venous glucose | after the baby is delivered | detected by a blood gase analyzer |
| Incidence of fetal acidosis | after the baby is delivered | Umbilical artery pH value\<7.20 |
| Incidence of hypotension | intraoperative | decrease of systolic blood pressure\>20% baseline values |
| Incidence of hypertension | intraoperative | increase of systolic blood pressure\>20% baseline values |
| Incidence of bradycardia | intraoperative | heart rate \<50 bpm |
| Incidence of nausea or vomit | intraoperative | observed by the anesthesiologist |
| Umbilical venous lactate | after the baby is delivered | detected by a blood gase analyzer |
Countries
China