A model to predict carboxyhemoglobin and pulmonary parameters after exposure to O2, CO2, and CO.

A computer-based physiological model of respiratory gas exchange, which considered variation in inhaled oxygen and carbon dioxide, was modified to include the effects of inhaled carbon monoxide. Output from the modified model consists of 60 variables, including blood, alveolar and tissue gases, ventilatory function and carboxyhemoglobin. Extensive testing demonstrated that this model produced accurate results for known problems and physiologically plausible results for situations in which the results were not empirically known. Estimates of the effects of simultaneous continuously varying exposure to carbon monoxide, oxygen and carbon dioxide cannot be practically obtained with other extant methods. The modified model receives input from two computer files containing environmental and subject physiological variables. These files allow a continuous dynamic multi-gas exposure simulation or actual exposure data profiles. Up to four outputs can be selected for plotting or stored in a file for later analysis.