Measurements of oxygen binding by whole human blood, at 37oC, at pH 7.4, and in the presence of 40mm of CO2 and normal physiological levels of BPG (5 mmol/L of cells), give the following:

Question

PO2 (mm Hg) = 10.6, 19.5, 27.4, 37.5, 50.4, 77.3, 92.3
% saturation (=100 x Theta) = 10, 30, 50, 70, 85, 96, 98

a). From these data, construct a binding curve, and estimate the percent oxygen saturation of blood at

(1) 100 mm Hg, the approximate partial pressure of O2 in the lungs, and
(2)30 mm Hg, the approximate partial pressure of O2 in venous blood.

b). Under these conditions, what percentage of the oxygen bound in the lungs is delivered to the tissues?

Answer 1

a) 99%
b) 56%
c) 42%
d) 63%