Abstract / Summary
Abstract Background Maternal hypotension remains one of the most frequent complications following spinal anesthesia for cesarean delivery and may adversely affect both maternal and fetal outcomes. Epinephrine infusion has recently emerged as a potential vasopressor strategy because of its combined α- and β-adrenergic activity. However, whether administration of an initial low dose epinephrine bolus before initiating infusion improves maternal hemodynamic stability remains unclear. This study evaluated the effect of adding a low dose epinephrine bolus prior to epinephrine infusion on maternal hemodynamic stability during cesarean delivery under spinal anesthesia. Methods Full term singleton pregnant women scheduled for elective cesarean delivery under spinal anesthesia were randomized into two groups. Patients in the bolus plus infusion group received an intravenous epinephrine bolus of 4 µg immediately after spinal anesthesia followed by continuous epinephrine infusion at 0.03 µg/kg/min. Patients in the infusion-only group received placebo saline bolus followed by the same epinephrine infusion regimen. The primary outcome was incidence of post-spinal hypotension defined as a systolic blood pressure decrease greater than 20% from baseline between spinal anesthesia and 5 minutes after delivery. Secondary outcomes included severe hypotension, reactive hypertension, tachycardia, rescue norepinephrine consumption, maternal adverse events, and neonatal outcomes. Results The incidence of hypotension was significantly lower in the epinephrine bolus group, occurring in 4 patients (10%) compared with 12 patients (30%) in the epinephrine infusion group, relative risk (RR) = 0.8, (95% CI 0.6–0.97; p = 0.025). Rescue norepinephrine requirements were significantly reduced in the bolus group. Maternal heart rate was generally higher in the bolus group without clinically significant increase in severe tachycardia or reactive hypertension. Neonatal Apgar scores and umbilical arterial blood gas parameters were comparable between groups. Conclusion Administration of a low dose epinephrine bolus before initiation of epinephrine infusion improved maternal hemodynamic stability during cesarean delivery under spinal anesthesia and reduced vasopressor rescue requirements without adversely affecting neonatal outcomes.