Relationship between oxygen saturation of mixed venous blood and pressure in the pulmonary artery trunk in healthy humans and patients with heart defects

Author： Vlasov Yu. Boboshko A.

Publisher： MAIK Nauka/Interperiodica

ISSN： 0362-1197

Source： Human Physiology, Vol.37, Iss.4, 2011-07, pp. : 422-429

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Abstract

The relationship between pulmonary artery pressure (P _LA) and oxygen saturation of mixed venous blood (S _V) has been studied in subjects (1750 men and 1026 women) subdivided into 12 groups. Functional relationships have been found between P _LA and S _V, P _LA = f(S _V), and S _V = f(P _LA), which were estimated using direct measurement of P _LA and S _V for each group. These factors have been found to obey the following dependences: P _LA = f(S _V) and P _LA = a(S _V)^−b, where b = −0.2284a + 0.6564 in men and b = −0.285a + 1.2947 in women; S _V = f(P _LA) and S _V = c(P _LA)^−d, where d = −0.25131Ln(c) + 1.0212; R ² = 0.8993 in men and d = −1.9645Ln(c) + 2.852; and R ² = 0.9674 in women. Each group occupies a position on the curves specified by the equations. Subjects with the diagnosis of a functional heart murmur and patients with congenital aortic valve stenosis were grouped together to form the so-called normal group characterized by specific P _LA = f(S _V) and S _V = f(P _LA) dependences. Male patients with coronary heart disease were also included in the normal group. An equation was derived to relate P _LA caused by different reasons with the corresponding saturation of mixed venous blood. In the case of the changing saturation of mixed venous blood, this equation gives the corresponding value of P _LA. Equilibrium between systemic and pulmonary circulations is established through interdependent changes in the physiological indices of blood circulation and gas exchange in humans.