Optical pH Measurements In Blood

Blood pH measurements present unique challenges due to the lack of a method to determine accuracy. Therefore an operational pH scale has been defined with the use of accepted pH standard buffer solutions in order to achieve precision and consistency. Historically, blood pH has been measured electrochemically with the glass electrode, in-vitro. The glass electrode is subject to drifts and to extraneous potentials that adds uncertainties to the measured values and must rely on frequent recalibrations to provide precision and consistency. A recent commercial entry, the fiber optic fluorescent pH sensor avoids these problems. The result is a stable sensor capable of continuous in-vivo monitoring of blood pH in spite of the intricacies introduced by the use of the operationally defined pH.