EFFECT OF PERFUSION MEDIA ON MYOCARDIAL OXYGEN TENSION IN ISOLATED RAT HEARTS

在许多“离体心脏”的实验中， 用95% O2平衡的晶体培养基灌注，以确保 充足的心肌氧分压，常用于研究心脏 功能，以提供足够的氧气代谢的需求。 然而，当血红蛋白可用于氧气运输时， 用21%O2平衡足以满足代谢需求。 这 一项研究使用EPR血氧测定法测量 用红细胞悬液灌注的离体心脏。 基线 红细胞灌注心脏的心肌pO2为16.4q3.5 mmHg（平均值qS.E.）。与之前的心肌测量结果相比， 用晶体培养基灌注的离体心脏中的pO2， 红细胞悬液导致低十倍水平的 心肌pO2，同时避免非常低和高的值。 标准 使用95%的氧气和晶体导致心肌水平 氧含量远高于通常在血红蛋白存在下发现的氧含量， 室内空气，但仍不能消除极低pO2的可能性 发生在心肌中。 极端的pO2可能导致生理性 异常和损坏。

In many experiments with "the isolated heart", typically it is perfused with crystalloid media equilibrated with 95% O2 to ensure adequate myocardial oxygen tension, is commonly used to study cardiac function in order to provide sufficient oxygen for metabolic demands. When hemoglobin is available for oxygen transport, however, equilibration with 21% O2 is adequate to meet metabolic demands. This study uses EPR oximetry forthe measurement of myocardial pO2 in isolated hearts perfused with an erythrocyte suspension. Baseline myocardial pO2 in erythrocyte-perfused hearts was 16.4q3.5 mmHg(meanqS.E.). When compared to previous measurements of myocardial pO2 in isolated hearts perfused with crystalloid media the use of erythrocyte suspensions resulted in a tenfold lower level of myocardial pO2 while avoiding very low and high values. The standard use of 95% oxygen with crystalloid results in myocardial levels of oxygen far above those usually found in the presence of hemoglobin and room air, while still not eliminating the potential for very low pO2 to occur in the heart muscle. Extremes of pO2 may cause physiological abnormalities and damage.