Ruiter J H, Spaan J A, Laird J D
Am J Physiol. 1978 Jul;235(1):H87-94. doi: 10.1152/ajpheart.1978.235.1.H87.
Oxygen uptake during myocardial hyperemia (MRH) following occlusions of 2.5-30 s was studied in nine anesthetized open-chest dogs by continuous measurement of left anterior coronary blood flow and anterior coronary vein oxygen saturation with electromagnetic flowmeter and fiber-optic catheters, respectively. The ratio of excess oxygen uptake to debt multiplied by 100% was defined as the oxygen repayment ratio (RR) and varied between -50% and +150% (mean 78%). Application of a steady-state Fick formula, as used by previous investigators, results in a profound overestimate of the RR (70-400%, mean 295%). RR is severely distorted by the venous catheter system, and after consideration of these effects we would conclude that the "true" RR in MRH is even lower than we found. Comparing our results with steady-state exercise autoregulation leads us to the following conclusions: 1) chemical kinetic limitations in oxygen release by red blood cells are excluded, 2) a simple direct PO2 regulation of flow is unlikely, but 3) our results are not inconsistent with a more complex integral oxygen regulation or with the metabolic hypothesis.
通过分别使用电磁流量计和光纤导管连续测量左前冠状动脉血流量和前冠状动脉静脉血氧饱和度，对9只麻醉开胸犬在2.5 - 30秒闭塞后心肌充血（MRH）期间的氧摄取进行了研究。将过量氧摄取与氧债的比值乘以100%定义为氧偿还率（RR），其范围在-50%至+150%之间（平均78%）。如先前研究者所使用的稳态菲克公式的应用，会导致RR被严重高估（70 - 400%，平均295%）。RR会因静脉导管系统而严重失真，在考虑这些影响后，我们得出结论，MRH中“真正的”RR甚至比我们所发现的还要低。将我们的结果与稳态运动自动调节进行比较，得出以下结论：1）排除了红细胞释放氧的化学动力学限制；2）不太可能存在简单的直接PO₂流量调节；3）我们的结果与更复杂的整体氧调节或代谢假说并不矛盾。
