The effects of ephedrine on maternal hypothermia in caesarean sections: a double blind randomized clinical trial

The purpose of the study was to investigate the effect of bolus and the combination of bolus and infusion of ephedrine on maternal hypothermia which are used for treating maternal hypotension under spinal anaesthesia.

110 ASA I-II patients who developed maternal hypotension were included into the study. Spinal anaesthesia was performed with 12.5 mg heavy bupivacaine + 15 µg fentanyl. Group I: Ephedrine bolus 5 mg plus ephedrine infusion, Group B: Ephedrine bolus 5 mg plus normal saline infusion. The systolic blood pressure was allowed to range between 20% from baseline values. Ephedrine solution infusion started after hypotension occurred (0.5 mg/minute). The body temperature under 35.5°C was accepted as hypothermia. The newborns' rectal temperature was measured. Moreover, the Apgar scores, umbilical vein-arterial blood gas and acid-base status were evaluated.

In Group I, the body core temperatures which were measured at 9, 18, 33, and 39th minutes were significantly higher than Group B (p < 0.05). The prevalence of maternal hypothermia in Group I was significantly lower than the Group B, which were as 65.5% (36/55) and 85.5% (47/55), respectively (p < 0.05). In Group I, the newborn rectal temperatures and the total dose of ephedrine were significantly higher than Group B (p < 0.05). In Group I, the systolic and mean blood pressures were higher than Group B (p < 0.05).

As a result, we found that combined bolus and infusion of ephedrine for treating maternal hypotension prevents maternal and neonatal hypothermia during caesarean section under spinal anaesthesia compared to bolus administrations alone.