Vasopressor Infusion in Cesarean Delivery

Maternal hypotension is a common complication after spinal anesthesia for cesarean delivery (CD). Many vasopressors have been used for prevention of post-spinal hypotension (PSH) during CD; however, the optimum protocol for prophylaxis is not established yet. Phenylephrine (PE) is a popular vasopressor used in obstetric anesthesia; however, its use is limited by its marked cardiac depressant nature. Norepinephrine (NE) is a potent vasopressor characterized by both α adrenergic agonistic activity in addition to a weak β adrenergic agonistic activity; thus, NE is considered a vasopressor with minimal cardiac depressant effect; these pharmacological properties would make NE an attractive alternative to PE. In this study, we will compare continuous variable infusion of both drugs (PE and NE) with doses of 0.75 mcg/Kg/min and 0.1 mcg/Kg/min respectively for prophylaxis against PSH during CD.

• Phenylephrine (Drug): Phenylephrine variable infusion with a starting rate of 0.75 mcg/Kg/min.
• Norepinephrine (Drug), also known as noradrenaline: Norepinephrine variable infusion with a starting rate of 0.1 mcg/Kg/min.
• Bupivacaine (Drug), also known as Marcaine: Bupivacaine will be injected in the subarachnoid space with a dose of 10 mg

Primary outcomes

• incidence of post-spinal anesthesia hypotension [30 minutes after spinal anesthesia]: Defined as the percentage of patients with decreased systolic blood pressure less than 80% of the baseline reading

Secondary outcomes

• incidence of severe post-spinal anesthesia hypotension [30 minutes after spinal anesthesia]: Defined as the percentage of patients with decreased systolic blood pressure less than 60% of the baseline reading
• incidence of severe delivery hypotension [10 minutes after delivery]: Defined as the percentage of patients with decreased systolic blood pressure less than 80% of the baseline reading
• systolic blood pressure [2 hours after subarachnoid block]: systolic blood pressure measured in mmHg
• diastolic blood pressure [2 hours after subarachnoid block]: diastolic blood pressure measured in mmHg
• heart rate [2 hours after subarachnoid block]: number of heart beats per minute
• APGAR score [10 minutes after delivery]: APGAR score of the fetus
• incidence of reactive hypertension [2 hours after spinal anesthesia]: Defined as the percentage of patients with increased systolic blood pressure more than 80% of the baseline reading

Sex: Female, ages: 18 Years to 40 Years

Inclusion Criteria:

* full term
* pregnant women
* scheduled for cesarean section

Exclusion Criteria:

* pre-ecpamsia
* eclampsia
* bleeding
* cardiac dysfuction

• Ahmed Mukhtar, Professor, Study director, Head of research committee section in anesthesia department