Kvietys P R, Navia C A, Premen A J, Granger D N
Am J Physiol. 1986 Oct;251(4 Pt 1):G446-52. doi: 10.1152/ajpgi.1986.251.4.G446.
Recently a two-component model of the intestinal circulation was proposed to explain the effects of vasodilators on intestinal oxygenation. This model assumes that the intestine is composed of two regions: one region in which oxygen uptake is blood flow independent (well perfused and normoxic) and a second region in which oxygen uptake is blood flow dependent (under-perfused and hypoxic). The model predicts that total intestinal oxygen uptake is increased by a vasodilator only if the blood flow-dependent region is affected. We used a systems analysis approach to predict the various boundary conditions that must be imposed on the two-component model for it to simulate experimental observations. The mathematical model was based on current concepts and available data regarding intestinal hemodynamics and oxygen exchange. The model simulations predict that 30-70% of the intestine must be hypoxic (regions where oxygen uptake is blood flow dependent) for the two-component hypothesis to adequately explain published observations. Since the existence of such an extensive hypoxic region seems unlikely for the normal intestine, the predictive value of the two-component hypothesis may be of limited value for describing the effects of vasodilators on oxygen uptake in the normal intestine. However, the two-component model may be useful in predicting the effects of vasodilators on intestinal oxygen uptake in the ischemic intestine.
最近，有人提出了一种肠循环的双组分模型，以解释血管舒张剂对肠氧合的影响。该模型假定肠由两个区域组成：一个区域的氧摄取与血流无关（灌注良好且氧含量正常），另一个区域的氧摄取与血流有关（灌注不足且缺氧）。该模型预测，只有当血流依赖区域受到影响时，血管舒张剂才会增加肠的总氧摄取量。我们采用系统分析方法来预测为使双组分模型模拟实验观察结果而必须施加在该模型上的各种边界条件。该数学模型基于有关肠血流动力学和氧交换的当前概念及现有数据。模型模拟预测，为使双组分假说能充分解释已发表的观察结果，30%至70%的肠必须处于缺氧状态（即氧摄取与血流有关的区域）。由于正常肠似乎不太可能存在如此广泛的缺氧区域，双组分假说对于描述血管舒张剂对正常肠氧摄取的影响的预测价值可能有限。然而，双组分模型可能有助于预测血管舒张剂对缺血肠氧摄取的影响。
