Method and apparatus for deriving oxygen association curves

Abstract

An apparatus and method for deriving an oxygen association curve for a blood sample wherein the sample is placed on a transparent support and is covered by a gas-permeable membrane element. The support is mounted in a gas treatment chamber with transparent windows on opposite sides of the support to provide an optical path through the support normal to the sample. Radiant energy is directed along this optical path, said radiant energy including two light frequencies, one having a wavelength at which there is substantially no change in absorbance as between oxygenated and deoxygenated blood and the other having a wavelength at which there is a relatively large change in absorbance as between oxygenated and deoxygenated blood. A controlled source of deoxygenating gas, such as nitrogen, and a controlled source of oxygen are connected to the chamber. An oxygen electrode is mounted in the chamber and generates the X component, corresponding to oxygen in the chamber, in an X-Y recorder. The difference in absorption of the two frequencies is measured and from this is derived a signal forming the Y component in the X-Y recorder, which thus provides a curve corresponding to the light absorbance changes in the sample while it is being oxygenated.