Effective monitoring of tissue oxygenation can help pinpoint areas likely to become necrotic in reconstructive surgery patients, for example. CEA-Leti researchers developed a compact sensor built on a CMOS matrix circuit and light-emitting diodes (LEDs). The sensor, worn directly on the patient's skin, measures tissue oxygen saturation (StO2).
A method known as spatially-resolved diffuse reflectance spectroscopy is used to illuminate the surface of the tissue at a specific location. The backscattered light is analyzed at several distances from the excitation point, providing information on the skin's absorption and scattering properties. This, in turn, provides the ratio of oxygenated and deoxygenated blood concentrations.
A clinical trial was conducted on some twenty subjects at Grenoble-Alpes University Medical Center. In qualitative terms, the results obtained were very similar to measurements taken with a reference sensor. Later, the device could be coupled with a CO2, sensor for less invasive respiratory monitoring, an innovation that could benefit people suffering from sleep apnea.
Next, CEA-Leti researchers will tackle the challenge of making the non-invasive system operable in real time. They are also continuing work to increase the device's quantitative sensitivity. In the long term, this could lead to advances in both inpatient and outpatient tissue oxygenation monitoring for certain pathologies.