Department of Anaesthesiology, Surgical Services and Intensive Care Medicine, Karolinska University Hospital, Solna SE-171 76, Sweden.
Br J Anaesth. 2014 May;112(5):824-31. doi: 10.1093/bja/aet486. Epub 2014 Feb 18.
It is important to be able to accurately monitor cardiac output (CO) during high-risk surgery and in critically ill patients. The invasiveness of the pulmonary artery catheter (PAC) limits its use, and therefore, new minimally invasive methods for CO monitoring are needed. A potential method is estimation of CO from endogenous carbon dioxide measurements, using a differentiated Fick's principle to determine effective pulmonary blood flow (EPBF). In this study, we aimed to validate a novel capnodynamic method (COEPBF) in a wide range of clinically relevant haemodynamic conditions.
COEPBF was studied in 10 pigs during changes in preload, afterload, CO increase, and bleeding. An ultrasonic flow probe around the pulmonary artery was used as reference method of CO determination. CO was also measured using a PAC thermodilution technique (COPAC). CO and other haemodynamic data were recorded before and during each intervention. Accuracy and precision and also the ability to track changes in CO were determined using Bland-Altman, four-quadrant plot and polar plot analysis.
COEPBF and COPAC showed equally good agreement, with a tendency to overestimate CO (bias 0.2 and 0.3 litre min(-1), respectively). The overall percentage error was 47% for COEPBF and 49% for COPAC. The concordance for tracking CO changes was 97 and 95% for COEPBF and COPAC, respectively, with an exclusion zone of 15% and radial limits of ±30°.
COEPBF showed reliable trending abilities, equivalent to COPAC. COEPBF and COPAC also showed low bias but high percentage errors. Further studies in animal models of lung injury and in high-risk surgery patients are warranted.
在高危手术和危重症患者中，能够准确监测心输出量（CO）非常重要。肺动脉导管（PAC）的侵入性限制了其使用，因此需要新的微创 CO 监测方法。一种潜在的方法是使用差异化的 Fick 原理从内源性二氧化碳测量中估计 CO，以确定有效肺动脉血流量（EPBF）。在这项研究中，我们旨在验证一种新的血流动力学方法（COEPBF）在广泛的临床相关血流动力学条件下的有效性。
在 10 头猪中，通过改变前负荷、后负荷、CO 增加和出血来研究 COEPBF。在肺动脉周围使用超声血流探头作为 CO 测定的参考方法。还使用 PAC 热稀释技术（COPAC）测量 CO。在每次干预前后记录 CO 和其他血流动力学数据。使用 Bland-Altman、四象限图和极坐标图分析来确定准确性、精密度以及跟踪 CO 变化的能力。
COEPBF 和 COPAC 显示出相当好的一致性，COEPBF 有高估 CO 的趋势（偏倚分别为 0.2 和 0.3 升/分钟）。COEPBF 的总体百分比误差为 47%，COPAC 的百分比误差为 49%。COEPBF 和 COPAC 分别有 97%和 95%的一致性用于跟踪 CO 变化，排除区为 15%，径向限制为±30°。
COEPBF 显示出可靠的趋势能力，与 COPAC 相当。COEPBF 和 COPAC 也显示出低偏差但高百分比误差。需要进一步在肺损伤动物模型和高危手术患者中进行研究。
