Monitoring system gas concentrations.

With proper measurement of inhaled and exhaled gas concentrations as well as end-tidal concentrations, patient concentrations of oxygen, carbon dioxide, and the volatile anesthetic agents may be inferred; additional information for vigilance monitoring, control of depth of anesthesia, and calculation of physiologic variables can be obtained. From this information, the anesthesiologist will be able to administer improved patient care through more immediate and complete knowledge and control of both equipment and patient function.