Effect of Alterations of Coronary Blood Flow on the Oxygen Consumption of the Nonworking Heart
Effect of Alterations of Coronary Blood Flow on the Oxygen Consumption of the Nonworking Heart
复制标题
冠状动脉血流变化对非工作心脏耗氧量的影响
作者：
R. Kahler;E. Braunwald;L. Kelminson;L. Kedes;C. Chidsey;Stanton Segal
在23个实验中研究了不同CBF和心肌O2输送对MVO2的影响。在14个实验中，对孤立的狗心脏进行了灌注，而在其他实验中，对体外循环维持的狗的心脏进行了研究。心室保持空，不产生压力，不做功，同时保持温度不变。通过向冠状动脉泵血来控制CBF和心肌O2输送，从心脏右侧采集冠状静脉总回流，并根据菲克原理计算稳定状态下的MVO2。冠脉静脉O2含量保持在4vol %以上，心肌O2提取量保持在78%以下，避免心肌缺氧。对42例患者在两种CBF水平下的MVO2（和O2输送）进行了比较，其中32例患者的11mv随着CBF的升高而大幅增加，反之亦然。10种例外情况均发生在O2输送量大大超过MVO2且O2萃取率低于35%的情况下。导致这些发现的基本机制尚不清楚，但讨论了一些可能的解释。
The effect of varying CBF and myocardial O2 delivery on MVO2 was studied in 23 experiments. In 14 of the experiments an isolated dog heart was perfused, while in the others the heart of a dog, whose systemic circulation was maintained on cardiopulmonary bypass, was studied. The ventricles were kept empty, developed no pressure and performed no external work, while their temperature was held constant. CBF and myocardial O2 delivery were controlled by pumping blood into the coronary arteries, total coronary venous return was collected from the right side of the heart and MVO2, was calculated during a steady state by the Fick principle. Myocardial anoxia was avoided by maintaining the coronary venous O2 content above 4 vol % and myocardial O2 extraction below 78%. A comparison of MVO2 at two levels of CBF (and O2 delivery) was made in 42 instances, and in 32 of them 11 MV increased substantially as CBF was elevated, or vice versa. The ten exceptions all occurred when O2 delivery greatly exceeded MVO2 with O2 extraction ratios below 35%. The fundamental mechanisms responsible for these findings are not clear, but a number of possible explanations are discussed.