Assessment of tissue oxygen tension: comparison of dynamic fluorescence quenching and polarographic electrode technique

Introduction and methods
Dynamic fluorescence quenching is a technique that may overcome some of the limitations associated with measurement of tissue partial oxygen tension (PO2). We compared this technique with a polarographic Eppendorf needle electrode method using a saline tonometer in which the PO2 could be controlled. We also tested the fluorescence quenching system in a rodent model of skeletal muscle ischemiahypoxia.

      Results
      Both systems measured PO2 accurately in the tonometer, and there was excellent correlation between them (r2 = 0.99). The polarographic system exhibited proportional bias that was not evident with the fluorescence method. In vivo, the fluorescence quenching technique provided a readily recordable signal that varied as expected.


      Discussion
      Measurement of tissue PO2 using fluorescence quenching is at least as accurate as measurement using the Eppendorf needle electrode in vitro, and may prove useful in vivo for assessment of tissue oxygenation.