BACKGROUD: Ephedrine has been most commonly used for the prevention and treatment of hypotension occurring frequently during spinal anesthesia for cesarean section. But recent studies reported that phenylephrine was more effective for treatment of maternal hypotension and for prevention of fetal acidosis than ephedrine. We compared effect of phenylephrine, ephedrine, and ephedrine combined with phenylephrine to maternal hypotension and fetal acidosis.

METHODS: This study compared ephedrine 2 mg/min infusion with 6 mg bolus (n = 30), phenylephrine 33.3µgram/min infusion with 50µgram bolus (n = 30), and ephedrine combined phenylephrine with half the dose infusion rate & bolus (n = 30). Hypotension, defined as systolic blood pressure less than 100 mmHg and less than 80% of baseline, was treated with additional bolus injection.

RESULTS: In ephedrine group, the number of bolus given for hypotension was larger than other groups (P < 0.001), the incidence of hypotension was also higher than other groups (P = 0.02). The heart rate was lower in phenylephrine group than other groups, but bradycardia which needs to be treated didn't occur. Umbilical blood gas analysis and Apgar score were similar for three groups, but only one patient in ephedrine group had fetal acidosis (pH = 7.130). Nausea and vomiting were more frequent in ephedrine group than other groups.

CONCLUSIONS: In our study, giving phenylephrine alone was more effective in the prevention and treatment of maternal hypotension and nausea & vomiting than giving ephedrine alone or combined phenylephrine.