Sidi A, Davis R F
Department of Anesthesiology, University of Florida College of Medicine, Gainesville.
J Cardiothorac Anesth. 1989 Jun;3(3):321-8. doi: 10.1016/0888-6296(89)90115-4.
Lactate extraction (defined as arteriovenous lactate concentration difference divided by arterial concentration and expressed as a percent) is often reported as the indicator of anaerobic cardiac metabolism in studies dealing with myocardial ischemia. However, lactate extraction ignores the effect of regional blood flow and, therefore, fails to consider the total mass of lactate consumed or produced (lactate flux). This study examined the relationship between lactate flux and calculated lactate extraction. Fourteen anesthetized dogs were instrumented to allow sampling of blood from the left anterior descending coronary artery (LADa) and vein (LADv) and a circumflex coronary vein (CFXv), as well as measurement of regional myocardial blood flow (RMBF) using microspheres, and measurement of systemic hemodynamic variables. Complete data sets (before LADa occlusion, after 15 minutes of LAD occlusion, and after 1 hour of reperfusion) were obtained in nine dogs. Only minor systemic hemodynamic changes occurred during LADa occlusion when compared with "before" and "after" values. Likewise, LADa occlusion produced only minor alterations in blood gas tensions, pH, concentrations of glucose, lactate, and RMBF in samples from the CFX perfusion zone. In contrast, LAD occlusion decreased RMBF in the LADa perfusion zone and produced significant hypercarbia and acidemia, as well as an increased LADv lactate concentration. In the LAD zone, lactate extraction decreased significantly from 15.9% +/- 7.0% before LAD occlusion to -77.4% +/- 21.8% during LAD occlusion (P less than 0.05). However, lactate flux (arteriovenous concentration difference x RMBF) in the LAD zone before and during LAD occlusion was not statistically significantly different (1.3 +/- 0.8 mg/min/100 g and -1.5 +/- 0.8 mg/min/100 g, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
在有关心肌缺血的研究中，乳酸摄取（定义为动静脉乳酸浓度差除以动脉浓度并以百分比表示）常被报告为无氧心脏代谢的指标。然而，乳酸摄取忽略了局部血流的影响，因此未能考虑消耗或产生的乳酸总量（乳酸通量）。本研究探讨了乳酸通量与计算得出的乳酸摄取之间的关系。对14只麻醉犬进行仪器植入，以便从左前降冠状动脉（LADa）和静脉（LADv）以及回旋冠状静脉（CFXv）采集血液样本，同时使用微球测量局部心肌血流量（RMBF），并测量全身血流动力学变量。在9只犬中获得了完整的数据集（LADa闭塞前、LAD闭塞15分钟后和再灌注1小时后）。与“之前”和“之后”的值相比，LADa闭塞期间仅出现轻微的全身血流动力学变化。同样，LADa闭塞仅使CFX灌注区样本中的血气张力、pH值、葡萄糖、乳酸浓度和RMBF发生轻微改变。相比之下，LAD闭塞使LADa灌注区的RMBF降低，并导致显著的高碳酸血症和酸血症，以及LADv乳酸浓度升高。在LAD区，乳酸摄取从LAD闭塞前的15.9%±7.0%显著降至LAD闭塞期间的-77.4%±21.8%（P<0.05）。然而，LAD闭塞前和闭塞期间LAD区的乳酸通量（动静脉浓度差×RMBF）在统计学上无显著差异（分别为1.3±0.8mg/min/100g和-1.5±0.8mg/min/100g）。（摘要截断于250字）
