Until now, the measurement of carbon dioxide blood pressure is done ex vivo, using an invasive process. This paper describes a first step toward a novel noninvasive process for in vivo measurement of this pressure. As first approximation, the blood solution is modeled as a simple aqueous solution of carbon dioxide in a cylindrical rigid canalization. The drift flux model and the Young–Laplace equation are employed to describe the fluid behavior. The numerical model relates the carbon dioxide pressure through the mixture pressure and velocity. The spatial distributions of these parameters are implemented to create linear mathematical relations between the mean mixture pressure and the radial velocity variation. As long as we are interested in a noninvasive measuring of the carbon dioxide pressure, a response model is proposed to describe the ultrasound signal backscattered by the considered solution. The linear relations are applied to deduce the carbon dioxide pressure through the measured radial velocity difference, using two computing methods of ultrasound signal. A comparative study is made between them showing the more appropriate process to compute the carbon dioxide pressure.

中文翻译：

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迈向 CO2 动脉压的无创测量方法

到现在为止，二氧化碳血压的测量已经完成离体，使用侵入性过程。本文描述了迈向新型非侵入性工艺的第一步体内这个压力的测量。作为第一个近似值，血液溶液被建模为圆柱形刚性管道中的简单二氧化碳水溶液。漂移通量模型和 Young-Laplace 方程用于描述流体行为。数值模型通过混合物压力和速度将二氧化碳压力联系起来。实施这些参数的空间分布以在平均混合压力和径向速度变化之间建立线性数学关系。只要我们对二氧化碳压力的无创测量感兴趣，就会提出一个响应模型来描述由所考虑的解决方案反向散射的超声信号。应用线性关系通过测量的径向速度差来推断二氧化碳压力，使用两种超声信号的计算方法。在它们之间进行了比较研究，显示了计算二氧化碳压力的更合适的过程。