Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.
Department of Bioengineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA.
Ann Biomed Eng. 2019 Apr;47(4):1094-1105. doi: 10.1007/s10439-019-02200-9. Epub 2019 Jan 18.
The effects of changing hematocrit (Hct) on the rate of circulatory oxygen ([Formula: see text]) delivery were modeled analytically to describe transfusion of 0.5-3.0 units of packed red blood cells (pRBC, 300 mL/unit, 60% Hct) to anemic patients. In our model, Hct affects [Formula: see text] delivery to the microcirculation by changing blood [Formula: see text] carrying capacity and blood viscosity, which in turn affects blood flow velocity and, therefore, [Formula: see text] delivery. Changing blood velocity impacts the [Formula: see text] delivery by affecting the oxygen diffusive losses as blood transits through the arteriolar vasculature. An increase in Hct has two opposite effects: it increases the blood [Formula: see text] carrying capacity and decreases the flow velocity. This suggests the existence of an optimal Hct that maximizes [Formula: see text] delivery. Our results show that maximal [Formula: see text] delivery occurs in the anemic range, where [Formula: see text]%. Optimal blood management is associated with transfusing enough units up to reaching maximal [Formula: see text] delivery. Although somewhat complex to implement, this practice would result in both substantial blood savings and improved [Formula: see text] delivery.
为描述给贫血患者输注 0.5-3.0 单位浓缩红细胞（pRBC，300 mL/单位，60%Hct）对循环氧输送率（[Formula: see text]）的影响，我们采用分析方法对其进行了建模。在我们的模型中，Hct 通过改变血液携氧能力和血液黏度来影响微循环中的[Formula: see text]输送，进而影响血流速度，从而影响[Formula: see text]输送。改变血液速度会通过影响血液在小动脉血管中输送时的氧气弥散损失来影响[Formula: see text]输送。Hct 的增加有两个相反的作用：它增加了血液的携氧能力，降低了流速。这表明存在一个最佳的 Hct 值，可以最大限度地提高[Formula: see text]输送。我们的结果表明，最大的[Formula: see text]输送发生在贫血范围内，即[Formula: see text]%。最佳的血液管理方法是输注足够的单位，直到达到最大[Formula: see text]输送。虽然实施起来有些复杂，但这种做法将带来大量的血液节省和改善的[Formula: see text]输送。
