Hemodynamic and antiemetic effects of prophylactic hyoscine butyl-bromide during cesarean section under spinal anesthesia: a randomized controlled trial

Abstract

Background: Abrupt bradycardia and hemodynamic instability during spinal anesthesia for cesarean section are not uncommon and are considered as one of the primary causes of intraoperative nausea and vomiting (IONV). We hypothesized that prophylactic use of hyoscine butyl-bromide (HBB) could improve hemodynamics and reduce IONV in parturients undergoing cesarean section.

Methods: A randomized, double-blind placebo-controlled trial was carried out in a tertiary university hospital, patients scheduled for elective cesarean section were equally randomized to receive either IV HBB 20 mg in 1 ml (Hyoscine group) or the same volume of 0.9% saline (Control group), one minute after spinal anesthesia. The primary endpoint was the incidence of intraoperative bradycardia (HR < 50 beats min-1). Secondary endpoints included changes in mean arterial blood pressure (MAP), the incidence of Intraoperative and Postoperative nausea or vomiting (IONV & PONV), the fetal heart rate and, Apgar score.

Results: Of the 160 subjects randomized, 80 received HBB and 80 received placebo. There was a significant reduction in the incidence of the primary endpoint of intraoperative bradycardia (HR < 50 beats min-1) in the Hyoscine group (0% vs 10%; OR = 0.05, 95% CI = [0.003, 0.93]; P = 0.004) compared with placebo. MAP showed an insignificant difference between groups over time. HBB significantly decreased incidences of IONV and PONV (p = 0.002 & 0.004) respectively.

Conclusions: In parturients undergoing cesarean section under spinal anesthesia, pretreatment with intravenous HBB was a safe measure for both the mother and the baby to reduce the risk of severe intraoperative bradycardia, but not hypotension. Furthermore, it was associated with less incidence of both IONV and PONV.

Trial registration: https://ichgcp.net/clinical-trials-registry/NCT04069078.

Keywords: Bradycardia; Cesarean section; Hyoscine N-Butylbromide; Spinal anesthesia; Vomiting.

Conflict of interest statement

The authors declare that they have no competing interests.

© 2022. The Author(s).

Figures

Fig. 1

CONSORT flowchart showing patient recruitment

Fig. 2

Serial changes in mean heart rate in both groups over time calculated using repeated-measures ANOVA followed by a post hoc Bonferroni test to identify significant differences. Data are shown as mean (standard deviation, S.D.). HR: heart rate. Group H: hyoscine group. Group C: control group. Postop: postoperative. (*), P-value < 0.05 comparing both groups at the same time point. aP < 0.05 compared to the baseline value in group C bP < 0.05 compared to the baseline value in group H. P < 0.05 was considered statistically significant

Fig. 3

Serial changes in mean arterial pressure (mmHg) in both groups over time calculated using repeated-measures ANOVA. Data are shown as mean (standard deviation, S.D.). MAP: mean arterial pressure. Group H: hyoscine group. Group C: control group. Postop: postoperative. aP < 0.05 compared to the baseline value in group C. bP < 0.05 compared to the baseline value in group H. P < 0.05 was considered statistically significant