氧摄取率：贫血时心肌代谢的有效指标。

Oxygen extraction ratio: a valid indicator of myocardial metabolism in anemia.

作者信息

Wilkerson D K, Rosen A L, Gould S A, Sehgal L R, Sehgal H L, Moss G S

出版信息

J Surg Res. 1987 Jun;42(6):629-34. doi: 10.1016/0022-4804(87)90006-0.

Abstract

We have shown that primates adequately compensate for acute normovolemic anemia to hematocrits (HCT) of 10%. We have described a whole-body extraction ratio (O2 consumption/O2 delivery; ER) of 50% as a reliable physiologic indicator of transfusion need. There is concern that whole-body ER may not accurately reflect impaired myocardial metabolism. The onset of significant lactate production by the left ventricle is an indicator of anaerobic metabolism. Our purpose is to compare left ventricular lactate metabolism (arterial-coronary sinus lactate; delta [L]) to ER in acute normovolemic anemia. Fourteen adult baboons were anesthetized, paralyzed, and ventilated on room air. Left atrial, coronary sinus, aortic, and Swan-Ganz catheters were inserted. Experimental animals (N = 7) were hemodiluted, at constant left atrial pressure (LAP), with 5% human serum albumin (HSA) to a HCT below 4%. Control animals (N = 7) underwent similar volume exchanges, also at constant LAP, with homologous RBCs resuspended in HSA. Whole-body extraction ratio and left ventricular lactate production were measured at baseline and at hematocrits of 20, 10, 6, and 4% in the experimental group. Data were obtained at similar volume exchange points in the control group. Significant lactate production occurred only in the experimental animals (P less than 0.05) when extraction ratio exceeded 50%. Significant lactate production does not occur before the whole-body ER exceeds 50%. ER appears to be a valid indicator of myocardial metabolism in anemia, in this setting.

摘要

我们已经表明，灵长类动物能够充分代偿急性正常血容量性贫血，使血细胞比容（HCT）降至10%。我们将50%的全身摄取率（氧耗量/氧输送量；ER）描述为输血需求的可靠生理指标。有人担心全身ER可能无法准确反映心肌代谢受损情况。左心室开始产生大量乳酸是无氧代谢的一个指标。我们的目的是比较急性正常血容量性贫血时左心室乳酸代谢（动脉-冠状窦乳酸；Δ[L]）与ER。14只成年狒狒在室内空气中麻醉、麻痹并进行通气。插入左心房、冠状窦、主动脉和Swan-Ganz导管。将实验动物（N = 7）在恒定左心房压力（LAP）下用5%人血清白蛋白（HSA）进行血液稀释，使HCT低于4%。对照组动物（N = 7）在相同的LAP下进行类似的容量交换，用悬浮在HSA中的同源红细胞进行。在实验组中，于基线以及血细胞比容为20%、10%、6%和4%时测量全身摄取率和左心室乳酸生成。在对照组的类似容量交换点获取数据。当摄取率超过50%时，仅在实验动物中出现显著的乳酸生成（P < 0.05）。在全身ER超过50%之前不会出现显著的乳酸生成。在这种情况下，ER似乎是贫血时心肌代谢的有效指标。