From the Department of Anesthesiology and Pain Medicine, Anesthesia and Pain Research Institute, Yonsei University College of Medicine (HJK, YSC, SHK, WL, D-HK) and Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Institute of Women's Life Medical Science, Yonsei University Health System, Seoul, Republic of Korea (J-YK).
Eur J Anaesthesiol. 2021 Apr 1;38(4):394-401. doi: 10.1097/EJA.0000000000001376.
Spinal anaesthesia-induced hypotension is frequently reported in patients undergoing caesarean section. Mechanistically, sympathetic blockade reduces the systemic vascular resistance and the left ventricular preload, causing hypotension, which is augmented by aortocaval compression. The corrected blood flow time (FTc) is affected by the preload and is inversely related to the afterload.
We hypothesised that the preanaesthetic carotid artery FTc could predict hypotension after induction in patients undergoing a caesarean section with spinal anaesthesia.
A prospective observational study.
A tertiary referral centre in South Korea from September 2018 to November 2019.
Thirty-eight parturients scheduled for elective caesarean section under spinal anaesthesia.
Using carotid ultrasonography, FTc was measured twice prior to inducing spinal anaesthesia. FTc was calculated using both Bazett's (B) and Wodey's (W) formulae. Hypotension was defined as an SBP decrease to less than 80 mmHg, or less than 75% of baseline, or if symptoms consistent with hypotension occurred from the time of injection of the spinal anaesthetic until delivery.
The primary endpoint was to determine the predictive value of preanaesthetic FTc for postspinal hypotension during caesarean delivery.
Among the 35 patients who completed this study, hypotension occurred in 21 (60%). The areas under the receiver-operating characteristic curves for FTc (B) and FTc (W) were 0.905 [95% confidence interval (CI), 0.757 to 0.978, P < 0.001] and 0.922 (95% CI, 0.779 to 0.985, P < 0.001), respectively. The optimal cut-off values for predicting hypotension were 346.4 and 326.9 ms, respectively. The grey zone for FTc (B) and FTc (W) included 40 and 14% of the patients, respectively.
Preanaesthetic carotid artery FTc was a reliable indicator of postspinal hypotension in parturients. Considering the grey zone, Wodey's formula is better than Bazett's formula.
ClinicalTrials.gov Identifier: NCT03631329.
剖宫产术中常发生椎管内麻醉引起的低血压。机制上，交感神经阻滞降低了全身血管阻力和左心室前负荷，导致低血压，而主动脉-腔静脉压迫则加剧了低血压。校正血流时间（FTc）受前负荷影响，与后负荷成反比。
我们假设，在接受椎管内麻醉的剖宫产患者中，麻醉前颈总动脉 FTc 可预测诱导后低血压。
前瞻性观察性研究。
韩国一家三级转诊中心，时间为 2018 年 9 月至 2019 年 11 月。
38 例择期行椎管内麻醉剖宫产的产妇。
在诱导椎管内麻醉前，使用颈动脉超声测量两次 FTc。FTc 分别用 Bazett （B）和 Wodey （W）公式计算。低血压定义为收缩压下降至 80mmHg 以下，或低于基础值的 75%，或从蛛网膜下腔麻醉注射到分娩时出现与低血压一致的症状。
主要终点是确定麻醉前 FTc 对剖宫产术中脊髓后低血压的预测价值。
在完成这项研究的 35 例患者中，21 例（60%）发生低血压。Bazett （B）和 Wodey （W）FTc 的受试者工作特征曲线下面积分别为 0.905 [95%置信区间（CI）：0.757 至 0.978，P<0.001]和 0.922 （95%CI：0.779 至 0.985，P<0.001）。预测低血压的最佳截断值分别为 346.4 和 326.9ms。Bazett （B）和 Wodey （W）FTc 的灰色区域分别包括 40%和 14%的患者。
麻醉前颈总动脉 FTc 是预测产妇脊髓后低血压的可靠指标。考虑到灰色区域，Wodey 公式优于 Bazett 公式。
ClinicalTrials.gov 标识符：NCT03631329。
