Comparison between different prophylactic & therapeutic phenylephrine regimenes in reducing maternal hypotention after induction of spinal anesthesia in caesarean section

1)Objectives: hypotension remains the most common complication of spinal anesthesia in cesarean section. A lot of studies have been performed to solve this problem but there are still controversies. This investigation was planned to find the best dose and the best way of phenylephrine administration to reduce the incidence of spinal anesthesia induced hypotension in cesarean section. 2) Design: 120 patients will be studied in 3 groups. Groups 1 & 2 will receive prophylactic 100 microgram bolus dose or 50 µg /min infusion of phenylephrine immediately after spinal anesthesia and the third group (placebo) will receive normal saline. 3) Setting & conduct:all of the drugs will be prepared in the same syringes with the same volume. The patient and the nurse who recorded the vital signs are not aware of the grouping. Patient’s blood pressure will be measured by non invasive blood pressure monitoring and will be recorded. In the case of hypotension which was defined as more than 20% decline in blood pressure compared to baseline, 100 µg phenylephrine in one ml volume will be injected in all three groups and if hypertension was detected, the infusing solution will be hold. 4): Participants including major eligibility criteria: all of the ASA 1 healthy term parturients referring to Fatemieh hospital candidate for Cesarean section will be included in the study. Exclusion criteria: chronic hypertension; preeclampsia; twin pregnancy;, preterm labor; allergy to drugs; cardiovascular disease; renal disease and previous abdominal surgeries with adhesion band and fibrosis. 5) Intervention: prophylactic bolus dose administration or infusion of phenylephrine 6) Main outcome measures variables:spinal anesthesia induced blood pressure change

Vice chancellor for Research and Technology, Hamadan University Of Medical Sciences