术前有这些要注意：术中低血压风险增加

本文由“小麻哥的日常”授权转载

腰麻后低血压是临床麻醉中很常见的一种现象，对于心肺不全的患者可能发生意外。

那么怎么处理呢？

▶️控制麻醉平面，平面越高，低血压的发生率越大

▶️适当扩容，可选择胶体溶液

▶️静脉注射缩血管药物

▶️警惕有无局麻药中毒，过敏等，也可能导致低血压，后果也更严重，必要时肾上腺素，心肺复苏，对症支持治疗等！

有没有简单明了的指标来预测腰麻后低血压呢？看看这篇病例对照研究的结果，找到哪些指标吧！

剖宫产腰麻期间低血压与心率变异度和血流动力学因素的关系：

一项病例对照研究

背景

剖宫产腰麻时低血压常发生，有潜在的不良反应。

目标

探讨与腰麻低血压相关的心率变异度和血流动力学因素。

设计：

一项随机研究的次级病例对照分析。

实施：

单一产科中心。

患者：

数据来源于230名健康足月单胎产妇，他们在腰麻下行择期剖腹产术。

干预：

在产妇休息时，使用Nexfin心脏监护仪记录连续的血流动力学数据。

术前基线值定义为连续测量5分钟的平均值。

在开始标准化腰麻后，给予血管升压药，使收缩压（SBP）维持在术前值的10%以内。

低血压的定义是从腰麻开始到胎儿分娩，任何10秒平均收缩压（MBP)低于术前值的80%。

将产妇分为病例组（低血压组）和对照组（血压正常组），采用单变量和多变量logistic回归模型确定与低血压相关的独立因素。

主要观察指标：

记录术前心跳间隔标准差（SDNN）、连续心跳间隔差均方根、低频高频比、SD1、SD2、近似熵、样本熵、平均动脉压、收缩压、每搏量变异、全身血管阻力指数、感觉阻滞高度，脊髓麻醉和胎儿分娩之间的静脉输液量和血管加压素的使用。

结果：

230例产妇中，113例（49.1%）出现低血压。

术前低SDNN[比值比（OR）：0.87，95%可信区间（CI）：0.78～0.97]，

高SD2（OR：25.06，95%CI：2.41～261.06），

低SBP（OR：0.98，95%CI：0.97～1.00）与低血压独立相关。

从脊髓麻醉到胎儿分娩之间，较低的感觉阻滞平面（OR：0.76，95%CI： 0.65至0.90）和较高的静脉输液量（OR：0.98，95%CI：0.96至0.99每15毫升变化）与较低的低血压发生率相关。

受试者工作特性曲线下面积为0.701。

结论

术前高SD2、低SDNN和低SBP与剖宫产腰麻期间低血压有关。

Heart rate variability and haemodynamic factors associatedwith hypotension during spinal anaesthesia for caesarean delivery: Acase–control study

BACKGROUND

Hypotension frequently occurs during spinal anaesthesia for caesareandelivery, with potential adverse effects.

OBJECTIVE

To investigate heart rate variability and haemodynamic factors associatedwith spinal anaesthesia-induced hypotension.

DESIGN

Secondary case–control analysis of a randomised study.

SETTING

Single obstetric centre.

PATIENTS

Data were obtained from 230 healthy term singleton parturients whounderwent elective caesarean delivery under spinal anaesthesia.

INTERVENTION

With parturients at rest, continuous haemodynamic measurements wererecorded using a Nexfin cardiac monitor. Baseline pre-operative values weredefined as the average of five minutes of continuous measurements. Afterinitiation of standardised spinal anaesthesia, vasopressors were administeredto maintain SBP within 10% of pre-operative values. Hypotension was defined asany 10 seconds average SBP less than 80% of pre-operative values frominitiation of spinal anaesthesia to foetal delivery. Parturients wereclassified into cases (hypotensive) or controls (normotensive), and bothunivariate and multivariable logistic regression models were used to identifyindependent factors associated with hypotension.

MAIN OUTCOME MEASURES

Pre-operative standard deviation of the interbeat interval (SDNN), rootmean square of successive interbeat difference, low-frequency to high-frequencyratio, SD1, SD2, approximate entropy, sample entropy, mean arterial pressure,SBP, stroke volume variation and systemic vascular resistance index wererecorded, as were sensory block height, intravenous fluid volume andvasopressor use between spinal anaesthesia and foetal delivery.

RESULTS

Of 230 parturients, 113 (49.1%) experienced hypotension. Pre-operativelower SDNN [odds ratio (OR) 0.87, 95% confidence interval (CI) 0.78 to 0.97],higher SD2 (OR 25.06, 95% CI 2.41 to 261.06), and lower SBP (OR 0.98, 95% CI0.97 to 1.00) were independently associated with hypotension. Between spinalanaesthesia to foetal delivery, lower sensory block height (OR 0.76, 95% CI0.65 to 0.90) and higher intravenous fluid volume (OR 0.98, 95% CI 0.96 to 0.99per 15 ml change) were associated with a lower incidence of hypotension. Areaunder the receiver operating characteristic curve was 0.701.

CONCLUSION

Pre-operative higher SD2, lower SDNN and lower SBP were associated withhypotension during spinal anaesthesia for caesarean delivery.