Effect on neonatal outcomes of maintenance of maternal blood pressure targets with noradrenaline after spinal anaesthesia for caesarean delivery: a multicentre, randomised, controlled trial.

Abstract

Hypotension after spinal anaesthesia for caesarean delivery can cause maternal and neonatal harm. However, excessive vasopressor therapy may also result in harm, and the optimal blood pressure target is unclear. We compared two different maternal blood pressure targets during caesarean delivery. Women with term pregnancies undergoing caesarean delivery under spinal anaesthesia were assigned randomly to maintenance of systolic blood pressure within 90% (SBP-90% group) or 80% (SBP-80% group) of baseline readings, from intrathecal injection until delivery. The primary outcome was umbilical artery pH. Secondary outcomes included incidence of umbilical artery pH < 7.2 and maternal adverse events. Data from 1183 women were analysed (SBP-90% group, n = 590; SBP-80% group, n = 593). There was no difference in the mean (SD) umbilical artery pH between the SBP-90% and SBP-80% groups (7.33 (0.04) vs. 7.33 (0.05), p = 0.11). There were fewer incidences of umbilical artery pH < 7.2 in women allocated to the SBP-90% group compared with the SBP-80% group (3 (0.5%) vs. 13 (2.2%), p = 0.020). Patients allocated to the SBP-90% group had fewer episodes of maternal hypotension (< 80% of baseline systolic; 213 (36.1%) vs. 418 (70.5%), p < 0.001); severe hypotension (< 60% of baseline systolic; 23 (3.9%) vs. 46 (7.8%), p = 0.006); and nausea and vomiting (58 (9.8%) vs. 109 (18.4%), p < 0.001). Patients allocated to the SBP-90% group received more noradrenaline boluses (median (IQR [range]) 2 (1-3 [0-14]) vs. 1 (0-2 [0-14]), p < 0.001) when compared with the SBP-80% control group. During caesarean delivery under spinal anaesthesia, maintaining maternal systolic blood pressure > 90% of baseline, compared with > 80% of baseline, with boluses of noradrenaline reduces the incidence of neonatal acidaemia, maternal hypotension and nausea and vomiting.