Study: NCT03252496

Intervention type: PROCEDURE
Group type: EXPERIMENTAL
Intervention: Spinal Anesthesia
Description: Performed at the L3-L4 or L4-L5 interspace using 27- or 25-gauge spinal needle

Intervention type: PROCEDURE
Group type: ACTIVE_COMPARATOR
Intervention: Spinal Anesthesia
Description: Performed at the L3-L4 or L4-L5 interspace using 27- or 25-gauge spinal needle

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Intrathecal Bupivacaine
Description: Bupivacaine 12.5 mg (2.5 mL 0.5%) will be administered in the subarachnoid space

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: Intrathecal Bupivacaine
Description: Bupivacaine 12.5 mg (2.5 mL 0.5%) will be administered in the subarachnoid space

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Intrathecal Fentanyl
Description: Fentanyl 15 μg will be administered in the subarachnoid space

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: Intrathecal Fentanyl
Description: Fentanyl 15 μg will be administered in the subarachnoid space

Intervention type: PROCEDURE
Group type: EXPERIMENTAL
Intervention: Cesarean Delivery
Description: Lower segment cesarean section using the Pfannenstiel incision

Intervention type: PROCEDURE
Group type: ACTIVE_COMPARATOR
Intervention: Cesarean Delivery
Description: Lower segment cesarean section using the Pfannenstiel incision

Intervention type: RADIATION
Group type: EXPERIMENTAL
Intervention: Ultrasound Assessment of the Inferior Vena Cava
Description: The inferior vena cava largest and smallest diameters will be measured proximal to the opening of the hepatic veins in the longitudinal axis with the M-mode using a 8-2 MHz curved array ultrasound probe placed longitudinally in the subcostal region

Intervention type: RADIATION
Group type: ACTIVE_COMPARATOR
Intervention: Ultrasound Assessment of the Inferior Vena Cava
Description: The inferior vena cava largest and smallest diameters will be measured proximal to the opening of the hepatic veins in the longitudinal axis with the M-mode using a 8-2 MHz curved array ultrasound probe placed longitudinally in the subcostal region

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: 250 mL Colloid over 5 minutes
Description: 6% hydroxyethyl starch 130/0.4 in 0.9% sodium chloride (voluven®) 250 mL will be administered over 5 minutes starting immediately after intrathecal injection

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: 250 mL Crystalloid over 5 minutes
Description: Ringer acetate 250 mL will be administered over 5 minutes starting immediately after intrathecal injection

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: 500 mL Crystalloid over 55 minutes
Description: Ringer acetate 500 mL will be administered over 55 minutes following colloid or crystalloid administration

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: 500 mL Crystalloid over 55 minutes
Description: Ringer acetate 500 mL will be administered over 55 minutes following colloid or crystalloid administration

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: 250 mL Colloid over 60 minutes
Description: After 60 minutes of intrathecal injection, 6% hydroxyethyl starch 130/0.4 in 0.9% sodium chloride (voluven®) 250 mL will be administered over 60 minutes

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: 250 mL Crystalloid over 60 minutes
Description: After 60 minutes of intrathecal injection, Ringer acetate 250 mL will be administered over 60 minutes

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Intravenous Ephedrine
Description: Intravenous ephedrine 3, 5, and 10 mg will be administered when Systolic blood pressure decreases below 120, 110, and 90 mmHg, respectively.

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: Intravenous Ephedrine
Description: Intravenous ephedrine 3, 5, and 10 mg will be administered when Systolic blood pressure decreases below 120, 110, and 90 mmHg, respectively.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Intravenous Syntocinon
Description: Immediately after delivery, syntocinon 10 IU will be added to the running crystalloid solution

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: Intravenous Syntocinon
Description: Immediately after delivery, syntocinon 10 IU will be added to the running crystalloid solution