Measurement of cardiac reserve in rat by impedance cardiography

摘要

Cardiac reserve is an important parameter to evaluate the cardiac function, and can be estimated from relative changes of the cardiac output. The impedance cardiography, for it's advantages of noninvasive, inexpensive, easy to operate and suitable for continuous determination, has already been recognized in both basic medical research and clinical practice. However, if the measurement of cardiac reserve is directly from calculating cardiac output by impedance cardiography, the measure value shall been effected disadvantageously by the factors of base impedance, resistivity value of blood, and the distance between the electrodes. Thus, a good idea for probing the methodology in measurement of cardiac reserve is both to keep the advantages of impedance cardiography adn to avoid the disadvantages in measurement of cardiac output by impedance. In addition, there are now no special suitable methods for measuring cardiac reserve of small animal like rat. Hereby, we established a method to measure the cardiac reserve of rat by electrically stimulating the sciatic nerve of the animal and then calculating the relevant parameters in impedance cardiogram.