COMPARISON OF INTRAVENOUS EPHEDRINE WITH PHENYLEPHRINE FOR THE MAINTENANCE OF ARTERIAL BLOOD PRESSURE DURING ELECTIVE CAESAREAN SECTION UNDER SPINAL ANAESTHESIA

The aim of this prospective study was to compare the effects of intravenous bolus of Ephedrine with Phenylephrine for the maintenance of maternal arterial blood pressure during elective Caesarean section under spinal anaesthesia. The study population included sixty two healthy parturients ASA I or ASA II at term with singleton pregnancy scheduled for elective Caesarean section who consented to spinal anaesthesia. Parturients were preloaded with 10ml/kg of crystalloid (Normal Saline or Ringers lactate) before the induction of spinal anaesthesia and 2.5 ml of 0.5% hyperbaric Bupivacaine was used for the spinal anaesthesia. Group A received intravenous bolus Ephedrine 5mg and Group B, Phenylephrine 100ug for the maintenance of maternal blood pressure Hypotension was defined as a decrease in systolic blood pressure of more than 30% below baseline or below 100mmHg. Bradycardia was defined as heart rate <60 beats/min. Patients’ characteristics, spinal block height and baseline haemodynamic values were similar in the two groups studied. Seven patients (22.5%) in the Ephedrine group and eight patients (25.8%) in the Phenylephrine group developed hypotension. 2 Both vasopressors effectively restored the systolic blood pressures but phenylephrine values were greater than ephedrine values and was statistically significant in the 15th minute of the procedure, with p value 0.04. Also, the intra operative diastolic blood pressures were higher in the phenylephrine group compared to the ephedrine group, and were significant in the 15th and the 20th minutes of the procedure with p value of 0.03 and 0.04 respectively. There was significant difference in heart rate between the two groups, analysis showed a higher heart rate values in ephedrine group compared to phenylephrine group which showed a downward trend with p value ranging from 0.01 to 0.04. The mean oxygen saturation trends in the two groups were similar, because all patients had oxygen therapy routinely in this study, the effect of the vasopressor or spinal anaesthesia could not be ascertained. Changes in the respiratory parameters showed no statistical difference between the two groups. Three patients (9.6%) developed nausea in the Ephedrine group and 4 (12.8 %) patients in the Phenyephrine group and these occurred in the hypotensive patients, no patient vomited during the procedure. 3 There was no need to repeat ephedrine or phenylephrine because no patient developed refractory hypotension. The mean APGAR Scores were similar for the two groups; no baby had Apgar score of < 8 in either group. In conclusion, Phenylephrine is safe and can be used as effectively as Ephedrine. It’s administration results in higher blood pressure values than Ephedrine in parturients undergoing Caesarean section under spinal anaesthesia.