Pulse oximetry: physical principles, technical realization and present limitations.

Oximetry for continuous patient monitoring has evolved to a mature technology that is clinically useful. Technologic limitations, however, still exist and there is need to develop more reliable, less expensive systems that will allow new applications such as fetal and home infant and adult monitoring. Although it is not possible to fully monitor patient blood gas status with a single variable, pulse oximetry provides an important view of the blood oxygen content that can be combined with other monitoring methods to more fully characterize patient status.