Monitoring tissue blood flow and oxygenation: a brief review of emerging techniques

This article describes promising emerging technologies developed for measuring tissue-level oxygenation or perfusion, each with its own inherent limitations. The end user must understand what the instrument measures and how to interpret the readings. Optical monitoring using near-infrared spectrometry, Doppler shift, and videomicroscopy are discussed in terms of their application at the tissue level. Assessment of the metabolic state of the extracellular space with existing technology and proxy indicators of metabolic status are discussed. Also addressed are potential sources of variation for each technique, and the role that the clinician plays in the proper interpretation of the data.