A model of constant-flow ventilation in a dog lung.
A model of constant-flow ventilation in a dog lung.
复制标题
狗肺恒流通气模型。
DOI：
10.1152/jappl.1988.64.5.2150
复制
发表时间：
1988
期刊：
影响因子：
--
通讯作者：
Slutsky,AS
中科院分区：
文献类型：
--
作者：
Ingenito,E;Kamm,RD;Watson,JW;Slutsky,AS
本文建立了一个半经验的恒流通气（CFV）模型，以检验具有以下特征的三区串联模型可以解释CFV期间观察到的充分CO2输送的假设：1）导管下游的射流再循环区，其中对流占主导地位;以及3）无湍流的外围区，其中输送由分子扩散和增强扩散控制。湍流涡流和心源性振荡之间的相互作用包括使用修改的泰勒色散理论，根据Kamm等人的公式。动脉PCO 2的预测值是合理的相似的实验结果为He-O2，空气和SF6-O2混合物的导管流速从0.2到1.6 l/s。气体交换的比阻抗被发现是最大的湍流混合区，其中运输是由低级别的涡流混合和分子扩散的末端附近。模拟结果表明，在CFV，心源性振荡增加气体交换主要是通过促进湍流涡流分散在远端气道，并通过延长湍流混合区的长度。即使导管的小位移也显示出对气体交换具有显著影响。
A semiempirical model of constant-flow ventilation (CFV) is developed to test the hypothesis that a three-zone serial model with the following characteristics can explain the adequate CO2 transport observed during CFV: 1) a zone of jet recirculation immediately downstream of the catheter in which convection dominates; 2) a zone influenced by turbulence but with little or no bulk flow; and 3) a peripheral zone, free of turbulence, in which transport is governed by molecular and augmented diffusion. Interactions between turbulent eddies and cardiogenic oscillations are included using a modification of Taylor dispersion theory according to the formulation of Kamm et al. Predicted values for arterial PCO2 are reasonably similar to experimental results for He-O2, air, and SF6-O2 mixtures for catheter flow rates from 0.2 to 1.6 l/s. Specific impedance to gas exchange was found to be largest immediately proximal to the end of turbulent mixing zone, where transport is governed by low-level eddy mixing and molecular diffusion. Simulations suggest that, during CFV, cardiogenic oscillations augment gas exchange primarily by promoting turbulent eddy dispersion in the distal airways and by extending the length of the turbulent mixing zone. Even small displacements of the catheter are shown to have a dramatic effect on gas exchange.