A comparative study of phenylephrine and ephedrine combination to ephedrine and phenylephrine alone for maintenance of blood pressure for caesarean delivery and their effects on foetal acid base status

Abstract

Introduction: Spinal anaesthesia is the preferred technique for caesarean section. Around 80% of which is complicated by maternal hypotension. Vasopressors are currently the treatment of choice for spinal-induced hypotension but these may individually have significant maternal or foetal side effects. Aim: To compare ephedrine and phenylephrine infusion with ephedrine and phenylephrine combination for preventing the hypotension in patients undergoing emergency caesarean section under spinal anaesthesia. Materials and Methods: A prospective randomized double blind study of 90 parturients beyond 32 weeks of pregnancy for caesarean section under spinal anaesthesia. Assuming a potency ratio of 80:1 ephedrine to phenylephrine, the patients were divided into the following three groups: Group E - received infusions of ephedrine 8 mg/ml, Group P - received infusions of 100 mcg/ml phenylephrine and Group E + P received infusion of ephedrine 4 mg/ml + phenylephrine 50 mcg/ml. A predefined algorithm was used to adjust the infusion rate according to the systolic blood pressure (SBP). After spinal injection, SBP, diastolic blood pressures (DBP), heart rate (HR) were recorded every one minute until the cord was clamped. Also, the vasopressor infusion rates were collected till clamping of umbilical cord in each group. Foetal parameters were analyzed from umbilical blood gas. Results: The incidence of hypotension was significantly higher in ephedrine group. The mean rate of infusion was higher for group E (P 0.05) as compared to others. Complications of bradycardia were observed in 30% of patients receiving phenylephrine. Conclusions: Combination of both phenylephrine and ephedrine is efficacious for spinal-induced hypotension with least maternal or foetal side effects.