Evaluation of the Effect of Norepinephrine, Ephedrine and Phenylephrine on Prophylaxis and Treatment of Hemodynamic Changes Associated with Spinal Anesthesia in Elective Cesarean Section Surgeries

Introduction: As recommended spinal anesthesia is the best technique for planned cesarean delivery. Moreover, it has been stated that vasopressors are more extensively accepted as effective agents in reduction of post spinal anesthesia (PSA) compared to fluid loading. Anyway, there is much debate on the most ideal vasopressor in preventing spinal hypotension during cesarean section. This agent should be capable of maintaining placental perfusion and maternal blood pressure with the least side effects on both fetus and mother. The main objective of the present study was to perform a comparison between prophylactic bolus doses of phenylephrine verses ephedrine and norepinephrine in both preventing and treatment of hemodynamic changes caused after spinal anesthesia in elective cesarean section. Another objective was to evaluate the effect of these agents on neonate. Materials and Methods: Our study consisted of 45 patients which were divided into three groups by random. In each group after basic monitoring and spinal anesthesia was performed, 5 mg of ephedrine, 5 micrograms of norepinephrine and 40 micrograms of phenylephrine were administered respectively. During the operation any possible changes in mean arterial blood pressure (MAP) and heart rate were recorded. Perioperative complications of both neonate and mother were controlled and recorded. Results: The MAP was higher in the norepinephrine group than the phenylephrine and ephedrine groups. The rate of blood pressure in both norepinephrine and phenylephrine groups was higher in comparison with ephedrine group (P = 0.001). MAP was slightly higher in norepinephrine group compared with phenylephrine group. However, in some point of time measuring this difference was significant. Maternal bradycardia was more common in the phenylephrine group with significant difference. (P = 0.003). No cases of vomiting were reported in any of the studied groups. Nausea was more common in ephedrine and phenylephrine groups without significant difference (P = 0.146). The rate of fetal metabolic acidosis in the ephedrine group was significantly higher compared with the other two groups (P = 0.043). Conclusion: Post-spinal hypotension in parturient undergoing cesarean delivery could be prevented successfully by prophylactic bolus doses of phenylephrine and norepinephrine which causes the least amount of drawbacks and fetal well-being in comparison with ephedrine.