Koncan D, Rifel J, Drevensek G, Kocijancic S, Ogorelec S, Budihna M V
University of Ljubljana, Faculty of Medicine, Dept. of Pharmacol. and Exp. Toxicol., Slovenia.
Pflugers Arch. 2000;440(5 Suppl):R143-4.
The porcine heart was used as a model for studying the thermal changes in myocardium at cooling and re-warming during open heart surgery. A section of the heart septum was excised and tissue was cut into two similar square slices. The same shape of the tissue, cut from the surface from the upper lateral wall of the left ventricle, covered with epicardium and fat, was taken for another measurement. A thin (<0.5 mm) square thermal source of the same length of the side as the tissue samples was put between the two slices of tissue. This set was placed in the middle of two identical copper cylinders (2r=50 mm, height=55 mm) used to keep the outer side of the specimen at controlled room temperature. Thermal conductivity of the heart tissue was determined at controlled thermal power, and known difference of the temperature at the edge of the tissue and at the middle of the heater, when steady state was reached. Thermal conductivity calculated from the temperature difference and the geometry of heater and samples was 0.75 W/m.K for septal heart tissue, and 0.60 W/m.K for the lateral wall ventricle tissue with epicardium and fat.
猪心被用作研究心脏直视手术中冷却和复温过程中心肌热变化的模型。切除一部分心脏隔膜，将组织切成两片相似的方形薄片。从覆盖有心外膜和脂肪的左心室上侧壁表面切下相同形状的组织用于另一项测量。将一个边长与组织样本相同长度的薄（<0.5毫米）方形热源置于两片组织之间。该装置放置在两个相同的铜圆柱体（2r = 50毫米，高度 = 55毫米）中间，用于将样本外侧保持在可控的室温下。在可控热功率下测定心脏组织的热导率，当达到稳态时，测定组织边缘和加热器中间已知的温度差。根据温度差以及加热器和样本的几何形状计算得出，隔膜心脏组织的热导率为0.75瓦/米·开尔文，带有心外膜和脂肪的左心室侧壁组织的热导率为0.60瓦/米·开尔文。
