A microcomputer oximeter for whole blood

A system is described for measuring the percent of oxyhemoglobin in flowing whole blood. The system consists of an Apple II+ computer, a commercially available analog-to-digital converter, a simple electronic circuit to illuminate blood with light at two appropriate wavelengths, and a short program in BASIC. This oximeter is shown to yield a linear measurement of oxyhemoglobin saturation when compared with standard oxygen analyses. Data can be sampled at a sufficiently rapid rate to yield an essentially continuous measurement in typical cardiovascular studies. The system can be implemented by the average investigator from standard electronic components. The oximeter program can be combined into a general-purpose data acquisition program, and 15 analog-to-digital channels remain available for gathering other data.