Introduction:

subarachnoid spinal block is the form of anesthesia more commonly used for elective cesarean section, though it carries the risk of maternal hemodynamic instability (hypotension or bradycardia). Vasopressors, such as ephedrine in bolus or infused norepinephrine, prevent this adverse event, though the evidence to guide vasopressor choice is insufficient.

Objectives:

to compare the frequency of hemodynamic instability events in women undergoing elective cesarean section with subarachnoid spinal block treated with ephedrine or norepinephrine.

Material and methods:

we performed a pragmatic, open-label, non-inferiority, phase IV clinical trial, in which the primary outcomes were the number of bradycardia and hypotension events. We also studied the number of nausea and vomiting events, severe adverse events, and Apgar scores.

Results:

infused norepinephrine reduced 71% the risk of hypotension, 93% the risk of nausea, and 67% the risk of vomiting. There were no differences in the number of bradycardia events or Apgar scores.

Conclusion:

norepinephrine is non-inferior to ephedrine to treat maternal hypotension due to subarachnoid spinal block in elective cesarean section.