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

  • Tinuola Abiodun Adigun

Abstract

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.

Published
2018-09-15
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