Determination of Oxygen Tension by Measurement of Net Charge Transport

Conventional electrodes that are used to measure oxygen tension in the biological environment have been plagued by one or more of three major problems: 1) flow sensitivity, 2) instability, and 3) inadequate response time. Pulsatile operation of the electrode has the potential of eliminating these problems. A new technique of measurement using integration of output current has been developed. This new method of measurement enhances the pulsatile operation in the Po2 electrode. The technique effectively determines the difference in charge transport that occurs during the polarization potential. Using this technique, it has been possible to measure net charge transport, which is proportional to the oxygen tension level of whole blood as early as 1 ms after application of the polarization pulse. Also, the subtraction of the discharging current component appears to stabilize electrode drift. The short polarization time required allows for the elimination of flow sensitivity by reducing the extension of the oxygen diffusion gradient to less than 8 ¿m from the electrode face. The short duration of active measurement will tend to decrease poisoning by allowing use of an operating duty cycle of minimal duration.