Comparison of Continuous Infusion and Bolus Phenylephrine for Prevention of Spinal-Induced Hypotension in Cesarean Section: A Quasi-experimental Study

Abstract

Cesarean section spinal anesthesia is often associated with maternal hypotension, which causes poor maternal and infant outcomes. Phenylephrine is commonly used as prophylaxis and treatment of spinal-induced hypotension, but the most effective mode of administration, bolus or continuous infusion, is controversial. Objectives: To compare the effectiveness of continuous phenylephrine infusion versus intermittent bolus administration in preventing spinal anesthesia–induced hypotension during elective cesarean section. Methods: A quasi-experimental study was carried out at the Department of Anesthesia, Gulab Devi Teaching Hospital, Lahore. Sixty-six ASA II patients, who had an elective cesarean section, were randomly divided into two groups, namely Group A (infusion, n=33), which received continuous phenylephrine infusion 30mL/hour, and Group B (bolus, n=33), which received 100 µg phenylephrine boluses when required. The data on hemodynamic, maternal side effects, and neonatal outcomes were taken and analyzed with SPSS version 28.0. Results: Continuous infusion resulted in significantly fewer hypotensive episodes (30.3% vs. 54.5%, p<0.001) and lower prevalence of nausea and vomiting (9.1% vs. 21.2%, p<0.004). Reactive hypertension occurred less frequently in the infusion group (3.0% vs. 12.1%, p<0.05). Neonatal outcomes were improved with infusion, including higher umbilical cord pH (7.37 ± 0.05 vs. 7.33 ± 0.06, p<0.002). Conclusion: Phenylephrine infusion was found to be better than bolus dosing in maternal hypotension prevention, reducing adverse maternal outcomes, and neonatal outcomes in cesarean section under spinal anesthesia. Infusion should be regarded as the regimen of choice in clinical practice.