Ephedrine for prevention hypotension; comparison between intravenous, intramuscular and oral administration during spinal anesthesia for elective cesarean section

ABSTRACT

To ameliorate post spinal anesthesia hypotension in patients undergoing cesarean section. To compare the incidence of maternal hypotension associated with spinal anesthesia for cesarean section when intravenous [IV], intramuscular [IM] or oral prophylactic boluses of ephedrine were used. Prospective randomized double blind Department of anesthesiology, Zainibiae Hospital, Shiraz University, Iran. June 2004 to November 2005. 60 ASA grade I-II pregnant mothers were enrolled. Spinal anesthesia was performed using 60-70 mg of 5% solution of lidocaine. The patients were divided into three equal groups [n=20]. Oral and IM ephedrine [25 mg] was administered to the first two groups 30 to 60 minutes before induction of anesthesia [Group A and B, respectively]. In the last 20 patients, IV Ephedrine [25 mg] was administered immediately after induction of spinal anesthesia [Group C]. Maternal blood pressure and pulse rate was checked every 2 minutes. Hypotension was promptly treated with 10-mg ephedrine boluses. Both IM and IV prophylactic doses of ephedrine significantly decreased the incidence of hypotension, compared to oral prophylactic dose of ephedrine [4/20 and 0/20 in the IM and IV ephedrine groups, respectively vs. 9/20 in the oral ephedrine group [p < 0.05]]. Oral prophylactic dose of ephedrine is not effective in preventing hypotension in pregnant women undergoing cesarean section with spinal anesthesia. Therefore, we only recommend a single bolus of IV ephedrine with a dose of 25mg