Department of Cardiac Anaesthesiology, Medanta the Medicity, Gurugram, Haryana, India.
Ann Card Anaesth. 2022 Jul-Sep;25(3):335-342. doi: 10.4103/aca.aca_44_21.
An ideal CO monitor should be noninvasive, cost effective, reproducible, reliable during various physiological states. Limited literature is available regarding the noninvasive CO monitoring in open chest surgeries.
The aim of this study was to compare the CO measurement by Regional Impedance Cardiography (RIC) and Thermodilution (TD) method in patients undergoing off pump coronary artery bypass graft surgery (OPCAB).
We conducted a prospective observational comparative study of CO measurement by the noninvasive RIC method using the NICaS Hemodynamic Navigator system and the gold standard TD method using pulmonary artery catheter in patients undergoing OPCAB. A total of 150 data pair from the two CO monitoring techniques were taken from 15 patients between 40-70 years at various predefined time intervals of the surgery.
We have tried to find out the accuracy, precision and cost effectiveness of the newer RIC technique. Mean CO, bias and precision were compared for each pair i.e.TD-CO and RIC-CO as recommended by Bland and Altman. The Sensitivity and specificity of cutoff value to predict change in TD-CO was used to create a Receiver operating characteristic or ROC curve.
Mean TD-CO values were around 4.52 ± 1.09 L/min, while mean RIC- CO values were around 4.77± 1.84 L/min. The difference in CO change was found to be statistically not significant (p value 0.667). The bias was small (-0.25). The Bland Altman plot revealed a mean difference of -0.25 litres. The RIC method had a sensitivity of 55.56 % and specificity of 33.33 % in predicting 15% change in CO of TD method and the total diagnostic accuracy was 46.67%.
A fair correlation was found between the two techniques. The RIC method may be considered as a promising noninvasive, potentially low cost alternative to the TD technique of hemodynamic measurement.
理想的 CO 监测仪应该是非侵入性的、经济有效的、在各种生理状态下可重复的、可靠的。关于开胸手术中的非侵入性 CO 监测，文献资料有限。
本研究旨在比较经胸阻抗法（RIC）和热稀释法（TD）在非体外循环冠状动脉旁路移植术（OPCAB）患者中的 CO 测量值。
我们进行了一项前瞻性观察性比较研究，使用 NICaS 血流动力学导航系统对 RIC 方法进行非侵入性 CO 测量，并使用肺动脉导管对接受 OPCAB 的患者进行金标准 TD 方法。在手术的各个预设时间间隔，从 40-70 岁的 15 名患者中获得了总共 150 对来自两种 CO 监测技术的数据。
我们试图找出较新的 RIC 技术的准确性、精度和成本效益。按照 Bland 和 Altman 的建议，比较每对即 TD-CO 和 RIC-CO 的平均 CO、偏差和精度。使用截断值预测 TD-CO 变化的灵敏度和特异性来创建接收者操作特征或 ROC 曲线。
TD-CO 的平均均值约为 4.52 ± 1.09 L/min，而 RIC-CO 的平均均值约为 4.77± 1.84 L/min。发现 CO 变化的差异在统计学上无显著性（p 值 0.667）。偏差较小（-0.25）。Bland Altman 图显示平均差值为-0.25 升。RIC 方法在预测 TD 方法 CO 变化 15%方面的灵敏度为 55.56%，特异性为 33.33%，总诊断准确性为 46.67%。
两种技术之间发现存在良好的相关性。RIC 方法可能被认为是一种有前途的非侵入性、潜在低成本的替代 TD 技术的血流动力学测量方法。
