Fig. 4.

In vivo testing of the oxygen sensing prototype in a porcine model. (a) Photograph of the experimental set-up. Blood flow was occluded in a front limb of a Yorkshire swine by applying a tourniquet over the elbow joint to induce changes in tissue oxygenation. The wearable was placed over a shaved area of skin on the upper limb. (b) Temperature and $p{O}_2$ (estimated from lifetime and intensity) during the experiment. As seen in both the estimates of $p{O}_2$ and temperature, the device is sensitive to physiological changes due to the compromised blood flow to the limb during the full occlusion. (c) Time derivatives of both partial oxygen pressure estimates reveal a faster rate of change of the local oxygenation for the minutes following application and removal of the tourniquet.