The effect of two dose phenylephrin for preventing hypotension during spinal anesthesia for cesarean delivery

Background: Spinal anesthesia-induced hypotension is one of the most complications which can cause many severe maternal and fetal complications. Therefore, the prevention and treatment of spinal anesthesia-induced hypotension in pregnant women undergoing cesarean delivery play an important role. The use of vasopressors is the most effective method of hypotensive prophylaxis and phenylephrine is currently the first-line vasopressor of choice to prevent this complication. The aim of this study is to evaluate the effectiveness and safety of two-dose phenylephrine for prevention of spinal anesthesia-induced hypotension during cesarean delivery. Materials and methods: In a randommized controlled clinical trial, 150 pregnants undregoing cesarean delivery with spinal anesthesia were randomly divided into three groups: Group I: as a control group without phenylephrine prophylaxis (n = 50), Group II: 50µg intravenously bolus phenylephrine (n = 50), and Group III: 75µg intravenously bolus phenylephrine (n = 50) immediately after induction of spinal anesthesia. Hypotension, defined decreasing systolic blood pressure > 20% of baseline. The incidence of hypotension, levels of hypotension, maternal side effects and neonatal APGAR scores at 1 and 5 minutes. Results: The incidence of hypotension was 44%, the incidence of re-hypotension was 16%. Group III: the incidence of hypotension was 28%, the incidence of re-hypotension was 2%. The neonatal APGAR scores of the two groups at both 1 minute and 5 minutes was the same (p > 0.05), all cases had APGAR > 7. Conclusion: Phenylephrine intravenous bolus at doses of 50 µg and 75 µg are both effective for the prevention spinal anesthesia-induced hypotension for cesarean section. However, the 75 µg phenylephrine dose was more effective than the 50 µg dose because of lower rates of hypotension and recurrent hypotension (28% and 2% vs 44% and 16%, p < 0.05). In addition, both groups of prophylactic phenylephrine didn’t cause detrimental adverses for parturients and their babies. Key words: Hypotensive prophylaxis, cesarean section, phenylephrin.