Phenylephrine and Ephedrine for Prevention of Hypotension in Women during Lower Segment Caesarean Section under Spinal Anaesthesia: A Randomised Clinical Study

Abstract

Introduction: Hypotension is the most common serious adverse event associated with Spinal Anaesthesia (SA) and is associated with nausea and vomiting leading to pulmonary aspiration, respiratory depression and cardiac arrest. Phenylephrine (PE) and Ephedrine (EP) are vasopressors commonly used for prevention of hypotension associated with SA. Aim: To compare the efficacy and safety of PE and EP in prevention of hypotension induced by SA in women during Lower Segment Caesarean Section (LSCS) surgery. Materials and Methods: The present randomised clinical study was conducted on 60 women, between 18-36 years of age and a Heart Rate (HR) of 60-100 per minute randomised to receive either 100 mcg Intravenous (i.v.) bolus of PE, or 12 mg i.v. of EP during intrathecal block. Women having intraoperative hypotension were injected additional doses of vasopressor. Cardiovascular parameters were recorded at baseline (before block) and then at 1, 5, 10, 15, 30, 40 and 60 minutes. Further, safety was also assessed based on hypotension events and adverse events reported during immediate postoperative period. Data analysis was done using IBM SPSS 17 and a p-value <0.05 was considered statistically significant. Results: The mean age of the study participants in PE and EP group was 26.67±5.40 and 26.23±4.59 years, respectively. Significant differences were observed between PE and EP groups for change in Systolic Blood Pressure (SBP) after 1, 10, 30, 40 and 60 minutes. Overall, there was a slight fall in SBP with PE, whereas, with EP there was a slight rise in SBP. Also, the Diastolic Blood Pressure (DBP) was maintained with EP throughout the 60 minute period, whereas with PE there was an initial rise in DBP followed by a slight fall in DBP. The Mean Arterial Pressure (MAP) was well maintained with PE throughout, whereas with EP there was a fall in MAP after 15 minutes. However, these changes were not clinically significant. The Pulse Rate (PR) was lower with PE compared to EP group at time points of 1, 5, 15 and 20 minutes. The mean respiratory rates and blood oxygen saturation were similar with PE and EP administration (p>0.05). A total of 13 (43.3%) patients in the PE group and 14 (46%) in the EP group had adverse events excluding hypotensive patients. Conclusion: According to the findings of the present study, the i.v. bolus of 100 mcg PE and 12 mg EP administered immediately after SA are equally effective in prevention of maternal hypotension and do not cause any significant cardiovascular and respiratory effects.