Long-Term In Vivo Oxygen Sensors for Peripheral Artery Disease Monitoring

Abstract

Tracking of tissue oxygenation around chronic foot wounds may help direct therapy decisions in patients with peripheral artery disease (PAD). Novel sensing technology to enable such monitoring was tested over 9 months in a Sinclair mini-pig model. No adverse events were observed over the entire study period. Systemic and acute hypoxia challenges were detected during each measurement period by the microsensors. The median time to locate the sensor signal was 13 s. Lumee Oxygen microsensors appear safe for long-term repeated oxygen measurements over 9 months.

Fig. 1

(a) Image of optical readers attached over sensors secured with wrap (blue) in the hind limbs of a pig and a pressure cuff (green). Optical readers non-invasively measured microsensors continuously during systemic and local oxygen challenges. (b) Example results of tissue oxygen measurements (LOI) versus time and description of protocol for systemic and local oxygen challenges

Fig. 2

Individual microsensor traces from eight separate sensors during systemic and local oxygen challenges 6 months post-injection. Graphs in the left column were tested with systemic oxygen challenges. Graphs in the right column were tested with systemic and local oxygen challenges. Anatomical location of black sensor trace is indicated on each graph. Grey traces are the other sensors with the same modulation types (systemic only or systemic and local oxygen challenges). Displayed are the LOI measurements versus time. Microsensors detected tissue oxygen reductions in response to systemic and local hypoxic events