Norepinephrine for the prevention of spinal-induced hypotension during caesarean delivery under combined spinal–epidural anaesthesia

Abstract

BACKGROUND During caesarean delivery under spinal anaesthesia hypotension may be managed by norepinephrine in preference to phenylephrine due a perception of less bradycardia and fewer reductions in cardiac output. OBJECTIVE As the optimum prophylactic dose of norepinephrine is unclear, we aimed to investigate its dose–response for preventing postspinal hypotension in caesarean delivery. DESIGN A randomised, double-blinded, dose-finding study. SETTING Jiaxing University affiliated Women and Children Hospital, Jiaxing, China. PATIENTS Ninety-nine patients undergoing elective caesarean delivery from 1 February to 5 August: excluding patients with ASA III or above, preeclampsia or hypertension, pre-existing or gestational diabetes, BMI more than 35 kg m−2, height less than 150 cm or with more than 175 cm, or with contraindications to local anaesthesia. INTERVENTIONS Patients received 0, 0.04, 0.05, 0.06 or 0.07 μg kg−1 min−1 preventive norepinephrine infusions immediately after intrathecal injection of 10 mg bupivacaine with 5 μg sufentanil. MAIN OUTCOME MEASURES The norepinephrine (Median effective dose) or (95% effective dose) ED50 and ED95, which were estimated using Probit analysis to compare haemodynamic changes associated with the different doses. RESULTS The incidence of hypotension was 70, 47.4, 40, 20 and 15% in the 0, 0.04, 0.05, 0.06 and 0.07 μg kg−1 min−1 groups, respectively. The ED50, ED80 and ED95 values were 0.029 (95% CI 0.008 to 0.042 μg kg−1 min−1), 0.068 (95% CI 0.055 to 0.099 μg kg−1 min−1) and 0.105 μg kg−1 min−1 (95% CI 0.082 to 0.172 μg kg−1 min−1), respectively. Apgar scores or umbilical arterial pH were similar among groups. CONCLUSION The ED50, ED80 and ED95 were 0.029, 0.068 and 0.105 μg kg−1 min−1 respectively. A 0.07 μg kg−1 min−1 norepinephrine infusion may be optimum for preventing postspinal hypotension after intrathecal injection of 10 mg bupivacaine combined with 5 μg sufentanil. TRIAL REGISTRATION Chinese Clinical Trial Registry (identifier: ChiCTR-TRC-1800014614).

Prophylactic norepinephrine infusion for postspinal anesthesia hypotension in patients undergoing cesarean section: A randomized, controlled, dose‐finding trial

“…In the current study, the incidence of postspinal anesthesia hypotension was as high as 68.42% (13/19) without using a prophylactic measure. Similar results were also reported in our previous study (62.24%, 61/98) 10 and by Wei et al 13 (70.00%, 14/20). Postspinal anesthesia hypotension remains a common complication during cesarean section with spinal anesthesia.…”

“…The ED50, ED85, and ED95 values for a prophylactic dose of norepinephrine were 0.029 (95% CI 0.008–0.042), 0.068 (95% CI 0.055–0.099), and 0.105 (95% CI 0.082–0.172) µg/kg/min, respectively. A loading bolus of 6 μg norepinephrine was given before norepinephrine infusion, and only bupivacaine was administrated for spinal anesthesia in our study; however, we found similar results, though different prophylactic doses were employed by Wei et al 13 The prophylactic doses of norepinephrine employed in our study was in accordance with Hasanin et al 7 and Fu et al 12 Significantly, the work reported by Hasanin et al 7 provided us a good foundation without exploring the ED50 and ED90 values. In addition, we further explored the overall stability of SBP control versus baseline, including MDPE and MDAPE.…”

“…The ED50 and ED90 values for a prophylactic dose of norepinephrine were 0.029 (95% CI −0.002 to 0.043) and 0.080 (95% CI 0.065–0.116) µg/kg/min, respectively. In another recent randomized, double‐blinded, dose‐finding study, Wei et al 13 compared four prophylactic doses of norepinephrine infusion (0.04, 0.05, 0.06, and 0.07 µg/kg/min) with NS. The authors indicated that the incidence of postspinal anesthesia hypotension in patients receiving 10 mg of hyperbaric bupivacaine and 5 mg of sufentanil spinal anesthesia was 47.4%, 40%, 20%, and 15% in the four prophylactic norepinephrine groups, respectively, and 70% in the NS group.…”

Comparison of two Norepinephrine rescue bolus for Management of Post-spinal Hypotension during Cesarean Delivery: a randomized controlled trial

“…The incidence of maternal hypotension in our patients was 38%. This incidence is similar to the incidence which was reported by Wei et al who used the same dose of NE infusion [12]. However, this incidence was relatively higher than that reported in our previous studies about cesarean delivery (∼ 30%) [5,6,13].…”

“…Two recent studies had suggested higher doses (0.07 mcg. Kg − 1 .min − 1 [12] and 0.08 mcg. Kg − 1 .min − 1 [18]); however, these studies were not available when we started our study.…”