A Comparative Study of Two Different Intravenous Bolus Doses of Phenylephrine Used Prophylactically for Preventing Hypotension after Subarachnoid Block in Cesarean Sections.

Background And Aims: Hypotension occurs in most of the cases following subarachnoid block in for cesarean sections. Studies comparing different bolus doses of phenylephrine for preventing hypotension induced by subarachnoid block in cesarean sections are sparse.

Settings And Design: This study was conducted to compare the efficacy of two different bolus doses of phenylephrine for preventing subarachnoid block-induced hypotension in cesarean sections.

Materials And Methods: Sixty parturients undergoing cesarean section were allocated into two groups. Group A ( = 30) received 150 mcg phenylephrine intravenously (IV) and Group B ( = 30) received 200 mcg phenylephrine IV prophylactically immediately after subarachnoid block. Then, for every 2 min, systolic blood pressure, diastolic blood pressure, mean arterial pressure (MAP), and heart rate (HR) were measured for 20 min, and APGAR scores were measured.

Statistical Analysis: The observations are expressed as mean ± standard deviation and were compared using unpaired -test. The statistical significance of difference between groups was based on value. < 0.05 was considered statistically significant.

Results: There was no difference in preventing hypotension in both the groups, the incidence in Group A being 16.6% and Group B also 16.6%. However, the rise in systolic pressure in Group B was higher than Group A in the first 2-6 min. The incidence of bradycardia was higher in Group B (43.3%) than Group A (20%).

Conclusions: Both the doses of phenylephrine were equally efficient in prevention of hypotension after subarachnoid block. Lower prophylactic bolus phenylephrine 150 mcg IV is better in the prevention of hypotension after subarachnoid block in cesarean sections as the incidence of bradycardia is higher with phenylephrine 200 mcg.