Background:

Hypotension is the most common adverse event when subarachnoid anesthesia is administered for cesarean section; multiple strategies for its prevention and management have been proposed, including the use of prophylactic vasopressors with inconclusive results.

Objective:

To evaluate the preventive efficacy of the use of phenylephrine in hypotension induced by subarachnoid anesthesia in pregnant women taken to caesarean section.

Methods:

A double-blind, controlled clinical trial in pregnant women, older than 18 years old, ASA 1 and 2, who received a subarachnoid anesthesia for cesarean section, were randomized to receive placebo or prophylactic infusion of phenylephrine 40 mcg / min, for 5 minutes.

Results:

140 patients were included in data analysis. Incidence of hypotension was higher in the control group than in the intervention group (AR 45.71% vs 32.85%). There were no significant differences between the two groups (p = 0.119). RR of hypotension in the intervention group were lower, independent of the criterion of hypotension [systolic blood pressure, RR 0.72 (95% CI 0.47-1.09), mean arterial pressure, RR 0.93 (95% CI 0.64-1.37), SBP or MAP 0.86 (RR 0.86) (IC95% 0.62-1.21)], but without significant differences p> 0.05. The use of vasopressors in patients who presented this event occurred in 75.4% (n = 52), with higher RR in the control group and significant differences when evaluating the two groups. (RR 1.4 p = 0.032).

Conclusions:

Prophylactic phenylephrine did not prove effective in reducing the incidence of hypotension, however, it is associated with a significant decrease in vasopressor requirements, as well as in the incidence of nausea and vomiting. MÉD.UIS. 2018;31(2):33-9.

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