What Is the Meaning of an Oxygen Measurement? : Analysis of Methods Purporting to Measure Oxygen in Targeted Tissues.

Clinical measurements of O ₂ in tissues will inevitably provide data that are at best aggregated and will not reflect the inherent heterogeneity of O ₂ in tissues over space and time. Additionally, the nature of all existing techniques to measure O ₂ results in complex sampling of the volume that is sensed by the technique. By recognizing these potential limitations of the measures, one can focus on the very important and useful information that can be obtained from these techniques, especially data about factors that can change levels of O ₂ and then exploit these changes diagnostically and therapeutically. The clinical utility of such data ultimately needs to be verified by careful studies of outcomes related to the measured changes in levels of O ₂ .