Schrock G D, Krahmer R L, Ferguson J L
Department of Physiology and Biophysics, University of Illinois, College of Medicine, Chicago 60680.
Am J Physiol. 1990 Aug;259(2 Pt 2):H635-8. doi: 10.1152/ajpheart.1990.259.2.H635.
Previous studies have reported significantly higher variability in coronary blood flow (CBF) measurements obtained by microsphere injection into the left ventricle (LV) as compared with microsphere injection into the left atrium (LA) of the rat. Questions have arisen concerning whether or not some of the variability may have been due to successive rather than simultaneous injections at the two sites, thereby giving measurements at different cardiovascular states. To address this question, we measured cardiac output (CO) and CBF as well as other systemic organ blood flows by employing simultaneous injection of two different sets of radiolabeled microspheres into the left atrium and left ventricle of semiconscious rats. Using this technique, CBF values (ml.min-1.g-1) of 5.45 +/- 0.43 and 5.24 +/- 0.46 for LA and LV injection sites, respectively, were measured (all values reported as means +/- SE). CO values (ml/min) of 67.5 +/- 3.5 for LA and 67.6 +/- 3.4 for LV were obtained. Paired left atrial and left ventricular measurements of CBF, CO, and other systemic organ blood flows using tracer microsphere methodology were not significantly different. All variabilities in these measurements by LA and LV injection were not significantly different. Our procedure did not significantly alter physiological parameters such as heart rate, mean arterial pressure, hematocrit, or blood gases. These findings indicate that, in our rat model, measurements made by LV microsphere injection are not only adequate for determining systemic blood flow at distal beds but provide coronary blood flow data with variability not significantly different from that of left atrial injection.
先前的研究报告称，与向大鼠左心房（LA）注射微球相比，通过向左心室（LV）注射微球来测量冠状动脉血流量（CBF）时，变异性显著更高。关于部分变异性是否可能是由于在两个部位进行连续而非同时注射所致，从而导致在不同心血管状态下进行测量，这一问题已引发关注。为解决这个问题，我们通过向半清醒大鼠的左心房和左心室同时注射两组不同的放射性标记微球，测量了心输出量（CO）、CBF以及其他全身器官的血流量。使用该技术，分别测量了LA和LV注射部位的CBF值（ml·min⁻¹·g⁻¹），LA注射部位为5.45±0.43，LV注射部位为5.24±0.46（所有值均报告为平均值±标准误）。获得的LA的CO值（ml/min）为67.5±3.5，LV的CO值为67.6±3.4。使用示踪微球方法对CBF、CO以及其他全身器官血流量进行的左心房和左心室配对测量并无显著差异。LA和LV注射在这些测量中的所有变异性均无显著差异。我们的操作并未显著改变诸如心率、平均动脉压、血细胞比容或血气等生理参数。这些发现表明，在我们的大鼠模型中，通过LV微球注射进行的测量不仅足以确定远端床的全身血流量，而且提供的冠状动脉血流量数据的变异性与左心房注射的变异性无显著差异。
