van't Veer Marcel, Geven Maartje C F, Rutten Marcel C M, van der Horst Arjen, Aarnoudse Wilbert H, Pijls Nico H J, van de Vosse Frans N
Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.
Med Eng Phys. 2009 Jul;31(6):688-94. doi: 10.1016/j.medengphy.2009.01.006. Epub 2009 Feb 23.
Direct volumetric assessment of coronary flow during cardiac catheterization has not been available so far. In the current study continuous infusion thermodilution, a method based on continuous infusion of saline into a selective coronary artery is evaluated. Theoretically, volumetric flow can be calculated from the known infusion rate (Q(i)), the temperatures of the blood (T(b)), the saline (T(i)), and the mixture downstream to the infusion site (T). We aimed to validate and optimize the measurement method in an in vitro model of the coronary circulation. Full mixing of infusate and blood was found to be the main prerequisite for accurate determination of the coronary flow. To achieve full mixing the influence of catheter design, infusion rate, and location of temperature measurement were assessed. We found that continuous infusion thermodilution slightly overestimated coronary flow determined by directly measured reference flow by 7+/-8%, over the entire physiological flow range of 50-250 ml/min. These results were found using a specially designed infusion catheter (infusion mainly through distally located sideholes), a high enough infusion rate (25 ml/min), and measurement of the mixing temperature between 5 and 8 cm distal from the tip of the infusion catheter. Absolute coronary flow rate can be measured reliably by the continuous infusion method when full mixing is present, under the conditions mentioned above.
目前，在心脏导管插入术中尚未实现对冠状动脉血流的直接容积评估。在本研究中，对连续输注热稀释法进行了评估，该方法是基于向选择性冠状动脉连续输注生理盐水的一种方法。理论上，容积流量可根据已知的输注速率（Q(i)）、血液温度（T(b)）、生理盐水温度（T(i)）以及输注部位下游混合液的温度（T）来计算。我们旨在在冠状动脉循环的体外模型中验证并优化该测量方法。发现输注液与血液充分混合是准确测定冠状动脉血流的主要前提条件。为实现充分混合，对导管设计、输注速率以及温度测量位置的影响进行了评估。我们发现，在50 - 250 ml/min的整个生理血流范围内，连续输注热稀释法所测定的冠状动脉血流比直接测量的参考血流略微高估了7±8%。这些结果是使用专门设计的输注导管（输注主要通过位于远端的侧孔进行）、足够高的输注速率（25 ml/min）以及在输注导管尖端远端5至8 cm处测量混合温度时得到的。在上述条件下，当存在充分混合时，连续输注法能够可靠地测量绝对冠状动脉血流速率。
