Preliminary study to validate the use of dynamic optical spectroscopy to monitor oxygen saturation changes in the carotid artery

Stroke is a leading global cause of long-term disability, and outcomes worsen with every minute until treatment. Despite this, there are no commercially available outpatient monitoring devices for stroke. A non-invasive, wearable patch developed in our laboratory may address this gap in patient care. We designed a flexible patch with a depth resolution of 16.5mm that uses dynamic vascular optical spectroscopy (DVOS) to record changes in reflected light intensity in the carotid artery in real-time. In this preliminary study, the left and right radial and carotid arteries of 10 healthy subjects were monitored while they performed a 30-second breath hold (BH) and 30 seconds of deep breathing (DB) in addition to normal breathing exercises. There were no statistically significant differences in the DVOS-derived % change of tissue oxygen saturation (StO2) from baseline in response to the BH or DB exercises between the radial and carotid arteries on the left and right sides. There was also no correlation between changes in StO2 and sex assigned at birth, race, or skin tone. These findings match what is expected for healthy subjects, indicating that our system may be able to monitor the StO2 through the carotid artery. This overcomes a previous challenge of poor depth resolution in DVOS systems. Our system offers a non-invasive, accurate way to monitor an important metric of cerebral blood perfusion in an outpatient setting, which may help to improve the standard-of-care for stroke.