Department of Veterinary Clinical Sciences and Veterinary Medical Center, The Ohio State University, Columbus, Ohio.
Transfusion. 2014 Mar;54(3):727-34. doi: 10.1111/trf.12354. Epub 2013 Jul 31.
It is well established that hematocrit (Hct) influences whole blood thromboelastography (TEG) tracings. Previous studies showed hypercoagulable TEG tracings in anemic patients despite clinical expectations that anemia often prolongs bleeding. TEG is a viscoelastic assessment of clot kinetics, and Hct is the main determinant of whole blood viscosity. TEG changes in anemia may be an in vitro artifact due to Hct effect on blood viscosity rather than true in vivo changes in hemostasis. The effect of changes in whole blood viscosity on TEG independent of Hct is not well understood.
Twenty-one blood samples from seven dogs were manipulated to produce one of three Hct conditions (45, 20, and 10%). Each was tested in two situations: viscosity adjusted to normal by adding alginate (ALG) or dilution with equal volume of saline (SAL). Both samples were analyzed with TEG simultaneously.
Twenty percent Hct plus ALG and 10% Hct plus ALG were significantly more viscous than their SAL counterparts (p=0.0156). Ten percent Hct plus SAL, 20% Hct plus SAL, and 45% Hct plus SAL all had different viscosities (p=0.006). Twenty percent Hct plus SAL and 10% Hct plus SAL had significantly shorter K and higher angle, MA, and G compared to their ALG counterparts as well as 45% Hct plus SAL (p<0.05).
ALG samples with low Hct, normal viscosity showed hypocoagulable tracings, whereas SAL samples with low Hct, low viscosity showed hypercoagulable tracings. TEG variables are influenced by whole blood viscosity altered with ALG, independently of Hct.
已有研究证实红细胞压积（Hct）会影响全血血栓弹力图（TEG）描记。尽管临床预期贫血常导致出血时间延长，但先前的研究表明贫血患者的 TEG 存在高凝状态。TEG 是对血凝块动力学的粘弹性评估，Hct 是全血粘度的主要决定因素。贫血时 TEG 的变化可能是由于 Hct 对血液粘度的影响所致的体外假象，而不是真正的体内止血变化。全血粘度变化对 TEG 的影响而不考虑 Hct 的影响尚不清楚。
从 7 只狗中采集 21 份血样，以产生 3 种 Hct 条件（45%、20%和 10%）之一。每种情况均在两种情况下进行测试：通过添加藻酸盐（ALG）将粘度调整至正常或用等体积生理盐水（SAL）稀释。同时用 TEG 对两种情况进行分析。
20%Hct+ALG 和 10%Hct+ALG 比其 SAL 对应物明显更粘稠（p=0.0156）。10%Hct+SAL、20%Hct+SAL 和 45%Hct+SAL 的粘度均不同（p=0.006）。与 ALG 对应物以及 45%Hct+SAL 相比，20%Hct+SAL 和 10%Hct+SAL 的 K 和角度更高，MA 和 G 更高（p<0.05）。
低 Hct 、正常粘度的 ALG 样本显示出低凝状态，而低 Hct 、低粘度的 SAL 样本显示出高凝状态。TEG 变量受 ALG 改变的全血粘度影响，而与 Hct 无关。
