Comparision between Intravenous Bolus of Phenylephrine and Ephedrine in Treating Spinal Hypotension in Lower Segment Cesarean Section

Abstract

BACKGROUND
We want to compare intravenous bolus of Phenylephrine and Ephedrine in treating the spinal
hypotension in lower segment caeserian section
MATRIALS & METHODS
It was an institution-based cross-sectional, observational study conducted in Patients who are
undergoing Lower Segment Cesarean Section admitted in the department of Obstetrics
&Gynaecology at a tertiary care hospital who satisfy inclusion criteria and who give informed
written informed consent during the period of May 2022 to May 2024.
RESULTS
The study demonstrates that phenylephrine and ephedrine have distinct effects on hemodynamic parameters during cesarean sections under spinal anesthesia. Phenylephrine
maintains higher SBP and MAP at specific intraoperative time points, while ephedrine
provides better DBP stability and induces higher pulse rates intraoperatively. Both drugs
contribute to overall hemodynamic stability, with their differential effects reflecting their
distinct pharmacological actions and implications for managing spinal-induced hypotension in
clinical practice. Systolic Blood Pressure (SBP): Phenylephrine demonstrated higher mean
SBP compared to ephedrine at specific intraoperative time points, notably at 5 minutes and 20
minutes intraoperatively. These differences were statistically significant, indicating that
phenylephrine effectively maintained higher SBP during these critical periods. However, at
other time intervals, there was no significant difference in SBP between the phenylephrine and ephedrine groups, suggesting variable trends but a consistent tendency towards higher SBP with phenylephrine. Diastolic Blood Pressure (DBP): Ephedrine exhibited higher mean values  of DBP at 1 minute, 5 minutes intraoperatively, and 30 minutes postoperatively, whereas phenylephrine showed higher mean DBP at 20 minutes intraoperatively. These differences were statistically significant, highlighting ephedrine's superiority in maintaining DBP stability
across multiple time points. Despite these differences, both drugs ensured hemodynamic
stability during cesarean sections. Mean Arterial Pressure (MAP): The mean arterial pressure
difference between phenylephrine and ephedrine was statistically significant at the 20-minutes
intraoperative time point, with phenylephrine showing higher values. However, at other time
points, there was no significant difference in MAP between the two groups. This indicates that
both drugs effectively stabilized MAP overall, with phenylephrine exerting a more pronounced
effect at 20 minutes intraoperatively. Heart Rate (HR): Ephedrine resulted in a statistically
significant higher pulse rate compared to phenylephrine at 5, 10, 20, 30, and 60 minutes
intraoperatively. In the postoperative period, the two groups' pulse rate difference was not
statistically significant. This reflects ephedrine's known beta-adrenergic effects, which
typically lead to increased heart rate, whereas phenylephrine tends to have minimal impact on
heart rate.