Oxygen respiratory gas analysis by sine-wave measurement: A theoretical model
Oxygen respiratory gas analysis by sine-wave measurement: A theoretical model
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DOI：
10.1152/jappl.1996.81.2.985
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发表时间：
1996-08-01
影响因子：
3.3
通讯作者：
Hahn, CEW
中科院分区：
文献类型：
--
作者：
Hahn, CEW
正弦强迫函数惰性气体交换模型（C.E.W.Hahn、A.M.S.Black、S.A.Barton 和 I.Scott.J.Appl.Physiol.75：1863-1876，1993）通过用氧气替换吸入的惰性气体进行修改，然后氧气在气相中的数学表现就好像它是惰性气体一样。开发了一种简单的扰动理论，将吸气、呼气末和混合呼气氧正弦波振荡的振幅与气道死腔体积和肺泡体积的比率联系起来。这些关系与耗氧量、气体交换率以及平均吸入分数 (FIo2) 和呼出氧分压无关：该模型还预测血流分流分数 (QS/QT) 与通过两个简单方程传输到呼气末以及动脉和混合静脉血的氧正弦波幅度扰动直接相关。当平均 FIo2 足够高以使动脉血红蛋白完全饱和时，氧气在血液中的数学行为就像低溶解度惰性气体，并且动脉和呼气末正弦波扰动的幅度与 QS/QT 直接相关。这种关系与平均动脉和混合静脉氧分压无关，并且也不受高强迫频率下混合静脉扰动的影响。当动脉血未完全饱和时，理论预测QS/QT与动脉血和混合静脉血中诱导饱和正弦波的振幅之比直接相关。因此，该模型预测：1) 可以通过在平均 FIo2 上添加氧正弦波扰动分量来在线计算气道死腔和呼气末肺容积； (2)QS/QT可以根据呼出气体以及动脉和混合静脉血中所得的氧扰动正弦波振幅来测量，并且与平均血氧分压和氧合血红蛋白饱和度值无关。这些计算可以在正弦波强制周期（通常为 2-4 分钟）更新。
A sinusoidal forcing function inert-gas-exchange model (C. E. W. Hahn, A. M. S. Black, S. A. Barton, and I. Scott. J. Appl. Physiol. 75: 1863-1876, 1993) is modified by replacing the inspired inert gas with oxygen, which then behaves mathematically in the gas phase as if it were an inert gas. A simple perturbation theory is developed that relates the ratios of the amplitudes of the inspired, end-expired, and mixed-expired oxygen sine-wave oscillations to the airways' dead space volume and lung alveolar volume. These relationships are independent of oxygen consumption, the gas-exchange ratio, and the mean fractional inspired (FIo2) and expired oxygen partial pressures: The model also predicts that blood flow shunt fraction (QS/QT) is directly related to the oxygen sine-wave amplitude perturbations transmitted to end-expired air and arterial and mixed-venous blood through two simple equations. When the mean FIo2 is sufficiently high for arterial hemoglobin to be fully saturated, oxygen behaves mathematically in the blood like a low-solubility inert gas, and the amplitudes of the arterial and end-expired sine-wave perturbations are directly related to QS/QT. This relationship is independent of the mean arterial and mixed-venous oxygen partial pressures and is also free from mixed-venous perturbation effects at high forcing frequencies. When arterial blood is not fully saturated, the theory predicts that QS/QT is directly related to the ratio of the amplitudes of the induced-saturation sinusoids in arterial and mixed-venous blood. The model therefore predicts that 1) on-line calculation of airway dead space and end-expired lung volume can be made by the addition of an oxygen sine-wave perturbation component to the mean FIo2; and (2) QS/QT can be measured from the resultant oxygen perturbation sine-wave amplitudes in the expired gas and in arterial and mixed-venous blood and is independent of the mean blood oxygen partial pressure and oxyhemoglobin saturation values. These calculations can be updated at the sine-wave forcing period, typically 2-4 min.