Efficient computer subroutines for interconversion of oxygen tension and saturation.

Two digital computer subroutines are described. NORSAT computes human hemoglobin saturation from oxygen tension data; NORINV performs the inverse computation. Each subroutine is based on an algorithm that is a direct mathematical inverse of the other. The effects of nonstandard conditions of temperature, pH, and CO2 tension on the saturation curve can be computed. The relative efficiency of these subroutines is compared to that of published subroutines having similar function. The new subroutines use computer time more efficiently with no loss of accuracy. The subroutines are provided in FORTRAN in a form suitable for direct inclusion in a number of user-specified programs.