Comparison of hemodynamic changes between phenylephrine and combined phenylephrine and glycopyrrolate groups after spinal anesthesia for cesarean delivery

Abstract

Background: Hypotension remains a common clinical problem of spinal anesthesia for cesarean delivery and phenylephrine is used as a vasopressor to address this. However, phenylephrine reduces maternal cardiac output (CO) due to reflex bradycardia. Glycopyrrolate is safe for the fetus, and increases heart rate (HR). Using a noninvasive measure of CO, we compared maternal hemodynamic changes between the phenylephrine only group (group P) and the phenylephrine plus glycopyrrolate group (group PG).

Methods: In this randomized study, 60 women scheduled for elective cesarean delivery were allocated to group P (n = 30) or group PG (n = 30). In both groups, phenylephrine was infused at 50 µg/min. This infusions stopped if systolic blood pressure (SBP) was higher than the baseline value, and phenylephrine 100 µg was injected if SBP was lower than 80% of the baseline value from spinal anesthesia to delivery. In group PG, glycopyrrolate 0.2 mg was injected intravenously after spinal anesthesia. Hemodynamic parameters, such as SBP, heart rate (HR), stroke volume index (SVI), cardiac index (CI) were measured before and until 15 min after spinal anesthesia.

Results: There were no significant differences in SBP and SVI compared to the baseline value in each group and between the two groups. HR and CI reduced significantly from 8 min to 15 min in group P compared to the baseline value as well as group PG for each time-point. However, HR and CI were maintained in group PG.

Conclusions: The use of glycopyrrolate added to phenylephrine infusion to prevent hypotension by spinal anesthesia for cesarean delivery was effective in maintaining HR and CI.

Keywords: Cesarean section; Glycopyrrolate; Hypotension; Phenylephrine; Spinal anesthesia.

Fig. 1

Heart rate changes during 15 minutes after spinal anesthesia. HR: heart rate. Group P: phenylephrine alone group. Group PG: phenylephrine plus glycopyrrolate group. ^*P < 0.05 compared to baseline value in group P. ^†P < 0.05 compared with group PG.

Fig. 2

Stroke volume index changes during 15 minutes after spinal anesthesia. SVI: Stroke volume index. Group P: phenylephrine alone group. Group PG: phenylephrine plus glycopyrrolate group.

Fig. 3

Cardiac index changes during 15 minutes after spinal anesthesia. CI: cardiac index. Group P: phenylephrine alone group. Group PG: phenylephrine plus glycopyrrolate group. ^*P < 0.05 compared to baseline value in group P. ^†P < 0.05 compared with group PG.

Fig. 4

Systolic blood pressure changes during 15 minutes after spinal anesthesia. SBP: Systolic blood pressure. Group P: phenylephrine alone group. Group PG: phenylephrine plus glycopyrrolate group.