去甲肾上腺素输注可预防剖宫产术中腰麻后低血压：剂量研究
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Norepinephrine Infusion for Preventing Postspinal Anesthesia Hypotension during Cesarean Delivery
背景与目的
去甲肾上腺素常被用于预防剖宫产时腰麻后低血压;但是，尚无关于其最佳剂量的研究。本研究的目的是比较输注三种不同浓度去甲肾上腺素对剖宫产术后低血压发生率的影响。
方 法
本研究为双盲、随机、对照试验，纳入对象为计划剖宫产的足月孕妇。腰麻后开始输注去甲肾上腺素。患者被随机分为三组,去甲肾上腺素注入浓度分别为 0.025 μg · kg-1 · min-1， 0.050 μg · kg-1 · min-1以及0.075 μg · kg-1 · min-1·。术中出现高血压时停止输液。主要指标是腰麻后低血压的发生频率(定义为收缩压下降低于基线读数的80%)。比较三组的收缩压、心率、术中高血压发生率、心动过缓发生率、新生儿结局。
结 果
本研究共纳入了244位产妇。腰麻后低血压发生率较低的为0.050-μg · kg-1 · min-1剂量组(23/93[24.7%],优势比:0.45(95%置信区间CI: 0.24 - 0.82), P = 0.014)和0.075-μg · kg-1 · min-1剂量组(25/96[26.0%],优势比:0.48(95%置信区间CI: 0.26 - 0.89), P = 0.022)与 0.025-μg · kg-1 · min-1剂量组(40/95 [42.1%])。与 0.025-μg · kg-1 · min-1剂量组相比，两个高剂量组(0.050-μg · kg-1 · min-1组和 0.075-μg · kg-1 · min-1组)的收缩压较高，心率较低。三组在术中高血压发生率、心动过缓发生率、新生儿结局等方面具有可比性。
结 论
与 0.025-μg · kg-1 · min-1剂量组相比，0.050-μg · kg-1 · min-1和0.075-μg · kg-1 · min-1的去甲肾上腺素浓度可有效减少剖宫产手术腰麻后低血压发生。
原始文献摘要
Onwochei D N, Ngan Kee W D, Fung L, et al. Norepinephrine Intermittent Intravenous Boluses to Prevent Hypotension During Spinal Anesthesia for Cesarean Delivery: A Sequential Allocation Dose-Finding Study.[J]. Anesthesia & Analgesia, 2017, 38(1):1.
Background: Norepinephrine has been recently introduced for prophylaxis against postspinal hypotension during cesarean delivery; however, no data are available regarding its optimum dose. The objective of this study is to compare three infusion rates of norepinephrine for prophylaxis against postspinal hypotension during cesarean delivery.
Methods: The authors conducted a double-blinded, randomized, controlled study including full-term pregnant women scheduled for cesarean delivery. Norepinephrine infusion was commenced after subarachnoid block. Patients were randomized into three groups, which received norepinephrine with starting infusion rates of 0.025 μg · kg-1 · min-1, 0.050 μg · kg-1 · min-1, and 0.075 μg · kg-1 · min-1. Infusion was stopped when intraoperative hypertension occurred. The primary outcome was the frequency of postspinal hypotension (defined as decreased systolic blood pressure less than 80% of the baseline reading). The three groups were compared according to the following: systolic blood pressure, heart rate, frequency of intraoperative hypertension, frequency of bradycardia, and neonatal outcomes.
Results: Two hundred eighty-four mothers were included in the analysis. The frequency of postspinal hypotension was lower for both the 0.050-μg · kg-1 · min-1 dose group (23/93 [24.7%], odds ratio: 0.45 [95% CI: 0.24 to 0.82], P = 0.014) and the 0.075-μg · kg-1 · min-1 dose group (25/96 [26.0%], odds ratio: 0.48 [95% CI:0.26 to 0.89], P = 0.022) compared with the 0.025-μg · kg-1 · min-1 dose group (40/95 [42.1%]). The two higher-dose groups (the 0.050-μg · kg-1 · min-1 group and the 0.075-μg · kg-1 · min-1 group) had higher systolic blood pressure and lower heart rate compared with the 0.025 μg · kg-1 · min-1 group. The three groups were comparable in the frequency of intraoperative hypertension, incidence of bradycardia, and neonatal outcomes.
Conclusions: Both the 0.050-μg · kg-1 · min-1 and 0.075-μg · kg-1 · min-1 norepinephrine infusion rates effectively reduced postspinal hypotension during cesarean delivery compared with the 0.025-μg · kg-1 · min-1 infusion rate.
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