A CLINICAL COMPARATIVE STUDY OF PROPHYLACTIC INFUSIONS OF PHENYLEPHRINE AND EPHEDRINE ON MATERNAL HEMODYNAMICS AND FETAL ACIDOSIS IN ELECTIVE CAESAREAN SECTION

Introduction: This randomized double blind study was started with an objective of comparing two commonly used vasopressors – ephedrine and phenylephrine in infusion form  with crystalloid co-hydration to reduce spinal anesthesia induced hypotension in elective caesarean section.

Methods: One hundred patients were randomized into two groups to receive either 100 μg/ml phenylephrine (group-P, n=50) or 5mg/ml ephedrine (group-E, n=50). Immediately after spinal injection the study solution was started prophylactically in every patient at the rate of 60ml/hr. A predefined algorithm was used to adjust the infusion rate according to the systolic blood pressure (SBP).

Results: Mean vasopressor required was significantly more in group-P than group-E (p<0.001). Incidence of hypotension were more in group-E than group P. Minimum systolic B.P and time to minimum systolic B.P. was lower in group-E compared to group-P (P value <0.001). Incidence of bradycardia was higher in group P and Incidence of nausea and vomiting was significantly higher in ephedrine group. Umbilical arterial pH and Umbilical Venous pH was lower in group-E and the difference was highly significant (P value <0.001). Apgar   score   at   5   min   was   similar in both groups.

Conclusion: Prophylactic phenylephrine infusion provides better maternal hemodynamic control as minimum systolic BP was higher and occurs later in comparison to ephedrine infusion. Incidence of nausea and vomiting was less with phenylephrine compared to   ephedrine. Ephedrine causes more acidosis in the fetus. Large doses of phenylephrine were used to maintain a baseline arterial pressure, despite this; there was no adverse effect on the fetus.