Hypotension associated with spinal anesthesia for cesarean delivery is most common and serious adverse effect despite the use of uterine displacement and volume preload. This study evaluated the role of ephedrine and fluid preload for prevention of hypotension during spinal anesthesia.

Sixty healthy women undergoing elective cesarean delivery under spinal anesthesia at term were allocated randomly to receive ephedrine 10µgram/kg/min followed by 4 mg bolus IV (E group, n = 20); ephedrine 10µgram/kg/min followed by 4 mg bolus IV and rapid administration of 500 ml hydroxyethyl starch solution (EH group, n = 20); and ephedrine 10µgram/kg/min followed by 4 mg bolus IV and rapid administration of 500 ml lactated Ringers solution (ER group, n = 20). Heart rate, blood pressure, hypotension incidence, and total ephedrine administration were checked after spinal anesthesia. Umbilical blood gas analysis and APGAR score were checked after delivery.

Maternal blood pressure, maternal heart rate, APGAR score were similar in three groups. But umbilical blood PaO₂ and PvO₂ is significantly low in hypotensive group than normotensive group (P < 0.05).

The results of the present study support the intravenous administration of ephedrine (4 mg bolus with 10µgram/kg/min) with or without 500 ml colloid or crystalloid infusion is not effective for blood pressure maintenance. Once the maternal hypotension induces the umbilical blood low oxygen tension, it is necessary for anesthesiologists to concentrate more on the maintenance of the blood pressure.