Comparison of intravenous ephedrine with phenylephrine for the maintenance of arterial blood pressure during elective caesarean section under spinal anaesthesia

Abstract

Hypotension is a major concern of the anaesthetists whenever subarachnoid block is performed especially in obstetric patients. Vasopressors have been shown to be more effective at limiting spinal hypotension than other treatment of hypotension like preloading and left uterine displacement. The aim of the study is to compare the effect of bolus intravenous Ephedrine with Phenylephrine for the maintenance of arterial blood pressure during elective caesarean section under spinal anaesthesia. This was a randomized, double blind, controlled study of sixty two healthy parturients American Society of Anesthesiologists' (ASA) status 1 and 2 at term with singleton pregnancy who consented to subarachnoid block at University College Hospital, Ibadan, Nigeria. The parturients were preloaded with 10 ml per kg of crystalloid before the induction of spinal anaesthesia with injection of 2.5 ml of 0.5% hyperbaric Bupivacaine at L3/L4 levels. Ephedrine 5 mg (group A; n = 31) or phenylephrine 100 ug (group B; n = 31) was given for the maintenance of arterial blood pressure. Results showed that the incidence of hypotension in the 62 patients was 24.2%. Both vasopressors effectively restored both the systolic and the diastolic blood pressure. There was significant difference in heart rate between the two groups. Nausea occurred in both groups and was found in hypotensive patients, no patient vomited during the procedure. The mean APGAR Scores were similar for the two groups; no baby had Apgar score of < 8 in either group. We concluded that phenylephrine is safe and can be used as effectively as Ephedrine. Its administration results in higher blood pressure than Ephedrine in parturients undergoing Caesarean Section under spinal anaesthesia.