Department of Maternal-Fetal Medicine, Fetal Medicine Research Institute, King's College London, UK.
Anaesthesia. 2020 Oct;75(10):1307-1313. doi: 10.1111/anae.15110. Epub 2020 May 29.
Maternal cardiac dysfunction is associated with pre-eclampsia, fetal growth restriction and haemodynamic instability during obstetric anaesthesia. There is growing interest in the use of non-invasive cardiac output monitoring to guide antihypertensive and fluid therapies in obstetrics. The aim of this study was to validate thoracic bioreactance using the NICOM® instrument against transthoracic echocardiography in pregnant women, and to assess the effects of maternal characteristics on the absolute difference of stroke volume, cardiac output and heart rate. We performed a prospective study involving women with singleton pregnancies in each trimester. We recruited 56 women who were between 11 and 14 weeks gestation, 57 between 20 and 23 weeks, and 53 between 35 and 37 weeks. Cardiac output was assessed repeatedly and simultaneously over 5 min in the left lateral position with NICOM and echocardiography. The performance of NICOM was assessed by calculating bias, 95% limits of agreement and mean percentage difference relative to echocardiography. Multivariate regression analysis evaluated the effect of maternal characteristics on the absolute difference between echocardiography and NICOM. The mean percentage difference of cardiac output measurements between the two methods was ±17%, with mean bias of -0.13 l.min and limits of agreement of -1.1 to 0.84; stroke volume measurements had a mean percentage difference of ±15%, with a mean bias of -0.8 ml (-10.9 to 12.6); and heart rate measurements had a mean percentage difference of ±6%, with a mean bias of -2.4 beats.min (-6.9 to 2.0). Similar results were found when the analyses were confined to each individual trimester. The absolute difference between NICOM and echocardiography was not affected by maternal age, weight, height, race, systolic or diastolic blood pressure. In conclusion, NICOM demonstrated good agreement with echocardiography, and can be used in pregnancy for the measurement of cardiac function.
母体心脏功能障碍与子痫前期、胎儿生长受限和产科麻醉期间血流动力学不稳定有关。人们越来越感兴趣的是使用非侵入性心输出量监测来指导产科的降压和液体治疗。本研究的目的是使用 NICOM®仪器通过胸生物电抗法验证与经胸超声心动图在孕妇中的相关性，并评估母体特征对每搏量、心输出量和心率绝对差值的影响。我们进行了一项前瞻性研究，纳入每个孕期的单胎妊娠女性。我们招募了 56 名 11-14 周妊娠、57 名 20-23 周妊娠和 53 名 35-37 周妊娠的女性。使用 NICOM 和超声心动图在左侧卧位下重复并同时评估心输出量，持续 5 分钟。通过计算相对于超声心动图的偏倚、95%一致性界限和平均百分比差异来评估 NICOM 的性能。多变量回归分析评估了母体特征对超声心动图和 NICOM 之间绝对差值的影响。两种方法的心脏输出量测量的平均百分比差异为±17%，平均偏差为-0.13 l.min，一致性界限为-1.1 至 0.84；每搏量测量的平均百分比差异为±15%，平均偏差为-0.8 ml（-10.9 至 12.6）；心率测量的平均百分比差异为±6%，平均偏差为-2.4 beats.min（-6.9 至 2.0）。当分析仅限于每个单独的孕期时，也得到了类似的结果。NICOM 与超声心动图之间的绝对差值不受母体年龄、体重、身高、种族、收缩压或舒张压的影响。总之，NICOM 与超声心动图具有良好的一致性，可在妊娠期间用于心脏功能的测量。
