Prophylactic Effects of Ephedrine, Ondansetron and Ringer on Hemodynamic Changes during Cesarean Section under Spinal Anesthesia - a randomized clinical trial.

Background: Hemodynamic change during spinal anaesthesia for cesarean section is prevalent.

Objective: Comparing the prophylactic effects of ephedrine, ondansetron and ringer on hemodynamic changes in patients undergoing cesarean section with spinal anaesthesia.

Material And Methods: This randomized clinical trial was carried out on pregnant women undergoing elective cesarean sec-tion referred to teaching hospitals of Mashhad, Iran. Patients allocated to three groups of intravenous ondansetron (O) (4 mg, 5 min),intramuscular ephedrine (E) (25 mg, 25 min) and ringer (R) (500 ml, 20 min) prior to spinal anaesthesia. Anaesthesia inducted with 10-15 mg of bupivacaine. Vital signs were recorded every 3 minutes for 18 minutes including systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), pulse rate (PR), pulse oximetry (SpO₂).

Results: Ninety patients with a mean age of 29.4 ± 5.4 years were studied in three groups of O (n = 30), E (n = 30), R (n = 30). Results showed a statistically significant difference in the incidence rate of hypotension 12 minutes after spinal anaesthesia in the three groups, but no statistically significant difference was found in the rest of minutes among the three groups. Dur-ing follow-up minutes, bradycardia was observed in only one patient (1.1%) of Group O and no cases of this sign were observed in other minutes and other groups.

Conclusion: Intramuscular administration of ephedrine 25 minutes prior to the spinal anaesthesia leads to better prevention of systolic blood pressure changes compared with intravenous ondansetron and ringer, while administration of ondansetron and ringer had the same effects on reducing hemodynamic changes.