Measuring the blood perfusion and microcirculation at a specific depth in human tissue is an important method to monitor oxygenation in critically ill patients. The optical probes, that are currently available in the market, are not capable of monitoring the blood perfusion from a given tissue layer and at a specific depth. We have designed a novel optical probe which is able to focus the light at a specific depth of ~670×μm in buccal tissue.
The new probe consists of two light guides for sending and detecting the reflected light from the sampling area (tissue), and a lens to focus the light into the desired depth of the tissue and collect it back from the same area. The new optical probe has been compared to a commercial laser Doppler probe by collecting data from the same sampling area. The result from our probe showed 15% higher accuracy in detecting changes in blood perfusion compared with an existing commercial probe.