Study: NCT03620942

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Phenylephrine
Description: Phenylephrine will be administered with conditions as below:~1. When systolic blood pressure is between 90-110% of baseline, 25mcg phenylephrine will be given either in infusion or bolus if heart rate ≥ 60 beats/min;~2. When systolic blood pressure is less than 90% of baseline, 25 to 75mcg phenylephrine will be given either in infusion or bolus if heart rate ≥ 60 beats/min.

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: Phenylephrine
Description: Phenylephrine will be administered with conditions as below:~1. When systolic blood pressure is between 90-110% of baseline, 25mcg phenylephrine will be given either in infusion or bolus if heart rate ≥ 60 beats/min;~2. When systolic blood pressure is less than 90% of baseline, 25 to 75mcg phenylephrine will be given either in infusion or bolus if heart rate ≥ 60 beats/min.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Ephedrine
Description: Ephedrine will be administered with conditions as below:~1. When systolic blood pressure is between 90-110% of baseline, 2mg ephedrine will be given either in infusion or bolus if heart rate \< 60 beats/min;~2. When systolic blood pressure is less than 90% of baseline, 2 to 6mg ephedrine will be given either in infusion or bolus if heart rate \< 60 beats/min.

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: Ephedrine
Description: Ephedrine will be administered with conditions as below:~1. When systolic blood pressure is between 90-110% of baseline, 2mg ephedrine will be given either in infusion or bolus if heart rate \< 60 beats/min;~2. When systolic blood pressure is less than 90% of baseline, 2 to 6mg ephedrine will be given either in infusion or bolus if heart rate \< 60 beats/min.

Intervention type: DEVICE
Group type: EXPERIMENTAL
Intervention: ADIVA System
Description: 1. When systolic blood pressure (SBP) is 100-110% of baseline, 25mcg phenylephrine (infusion) is given if heart rate ≥ 60 beats/min, and 2mg ephedrine (infusion) is given if heart rate \< 60 beats/min;~2. When SBP is 90-100% of baseline, 25mcg phenylephrine (infusion or bolus) is given if heart rate ≥ 60 beats/min, and 2mg ephedrine (infusion or bolus) is given if heart rate \< 60 beats/min;~3. When SBP is 80-90% of baseline, 50mcg phenylephrine (infusion or bolus) is given if heart rate ≥ 60 beats/min, and 4mg ephedrine (infusion or bolus) is given if heart rate \< 60 beats/min;~4. When SBP \< 80% of baseline, 75mcg phenylephrine (infusion or bolus) is given if heart rate ≥ 60 beats/min, and 6mg ephedrine (infusion or bolus) is given if heart rate \< 60 beats/min.

Intervention type: DEVICE
Group type: ACTIVE_COMPARATOR
Intervention: DIVA System
Description: DIVA system works as below:~1. When systolic blood pressure is between 90 to 100% of baseline, 25mcg phenylephrine (bolus) will be given if heart rate ≥ 60 beats/min, whereas 2mg ephedrine (bolus) will be given if heart rate \< 60 beats/min;~2. When systolic blood pressure is less than 90% of baseline, 50mcg phenylephrine (infusion or bolus) will be given if heart rate ≥ 60 beats/min, whereas 4mg ephedrine (infusion or bolus) will be given if heart rate \< 60 beats/min.