Brighenti Chiara, Gnudi Gianni, Avanzolini Guido
Biomedical Engineering Unit, Department of Electronics, Computer Science and Systems (DEIS), University of Bologna, Viale Risorgimento 2, 1-40136 Bologna, Italy.
Physiol Meas. 2003 May;24(2):261-75. doi: 10.1088/0967-3334/24/2/303.
This paper presents a mathematical model of the oxygen alveolo-capillary exchange to provide the capillary oxygen partial pressure profile in normal and pathological conditions. In fact, a thickening of the blood-gas barrier, heavy exercise or a low oxygen partial pressure (PO2) in the alveolar space can reduce the O2 alveolo-capillary exchange. Since the reversible binding between haemoglobin and oxygen makes it impossible to determine the closed form for the mathematical description of the PO2 profile along the pulmonary capillaries, an approximate analytical solution of the capillary PO2 profile is proposed. Simulation results are compared with the capillary PO2 profile obtained by numerical integration and by a piecewise linear interpolation of the oxyhaemoglobin dissociation curve. Finally, the proposed model is evaluated in a large range of physiopathological diffusive conditions. The good fit to numerical solutions in all experimental conditions seems to represent a substantial improvement with respect to the approach based on a linear approximation of the oxyhaemoglobin dissociation curve, and makes this model a candidate to be incorporated into the integrated descriptions of the entire respiratory system, where the datum of primary interest is the value of end capillary PO2.
本文提出了一种氧气肺泡-毛细血管交换的数学模型，以提供正常和病理条件下毛细血管氧分压分布情况。事实上，血气屏障增厚、剧烈运动或肺泡空间中氧分压（PO2）降低都会减少氧气肺泡-毛细血管交换。由于血红蛋白与氧气之间的可逆结合使得无法确定沿肺毛细血管的PO2分布的数学描述的封闭形式，因此提出了毛细血管PO2分布的近似解析解。将模拟结果与通过数值积分以及氧合血红蛋白解离曲线的分段线性插值获得的毛细血管PO2分布进行了比较。最后，在大范围的生理病理扩散条件下对所提出的模型进行了评估。在所有实验条件下与数值解的良好拟合似乎代表了相对于基于氧合血红蛋白解离曲线线性近似的方法的实质性改进，并使该模型成为纳入整个呼吸系统综合描述的候选模型，其中主要关注的数据是毛细血管末端PO2的值。
