SEM scanner sensing apparatus, system and methodology for early detection of ulcers
A handheld, conforming capacitive sensing apparatus configured to measure Sub-Epidermal Moisture (SEM) as a mean to detect and monitor the formation of pressure ulcers. The device incorporates an array of electrodes which are excited to measure and scan SEM in a programmable and multiplexed manner by a battery-less RF-powered chip. The scanning operation is initiated by an interrogator which excites a coil embedded in the apparatus and provides the needed energy burst to support the scanning/reading operation. Each electrode measures the equivalent sub-epidermal capacitance corresponding and representing the moisture content.
1. A Sub-Epidermal Moisture (SEM) sensing apparatus, comprising:
a substrate comprising a rigid stiffener,
a bipolar radiofrequency (RF) sensor comprising a first electrode and a second electrode that are both fixedly coupled to a first side of the substrate,
an insulating cover layer fixedly disposed over the first and second electrodes and is coupled to the first side of the substrate, and wherein the insulating cover layer is configured to act as a barrier between a tissue being measured and the first and second electrodes,
a pressure sensor that is coupled to the substrate and configured to sense a pressure that is applied to the substrate, and
an electronics package that is individually wired to each of the first and second electrodes and the pressure sensor, and the electronics package is configured to:
measure a pressure as sensed by the pressure sensor, and
measure a capacitance between the first and second electrodes when the pressure is within a defined pressure range,
wherein the capacitance is an indicator of the SEM.
2. The SEM sensing apparatus of claim 1 , further comprising an enclosure, and wherein the substrate is movably coupled to the enclosure.
3. The SEM sensing apparatus of claim 2 , wherein the pressure sensor is disposed between the enclosure and the substrate.
4. The SEM sensing apparatus of claim 3 , wherein the pressure sensor is disposed in line with the first and second electrodes.
5. The SEM sensing apparatus of claim 2 , wherein the electronics package is disposed within the enclosure.
6. The SEM sensing apparatus of claim 1 , wherein the second electrode is an annular electrode that is disposed around the first electrode.
7. The SEM sensing apparatus of claim 6 , wherein the second electrode is concentrically disposed around the first electrode.
8. The SEM sensing apparatus of claim 6 , wherein the first electrode and the second electrode are configured such that there is an annular gap between the first and second electrodes.
9. The SEM sensing apparatus of claim 8 , wherein the annular gap is uniform.
10. The SEM sensing apparatus of claim 1 , wherein the first and second electrodes are electrically insulated from each other.
11. The SEM sensing apparatus of claim 1 , wherein the substrate comprises a second side, and wherein the pressure sensor is coupled to the second side of the substrate.
12. The SEM sensing apparatus of claim 1 , wherein the electronics package is configured to measure the capacitance between the first and second electrodes by emitting and receiving radio frequency (RF) energy.
13. The SEM sensing apparatus of claim 12 , wherein the first and the second electrodes are coupled to the electronic package to form a bipolar RF sensor.