Apparatus and methods for determining damaged tissue using sub-epidermal moisture measurements
The present disclosure provides apparatuses and computer readable media for measuring sub-epidermal moisture in patients to determine damaged tissue for clinical intervention. The present disclosure also provides methods for determining damaged tissue.
1. An apparatus for identifying sub-epidermal moisture (SEM), said apparatus comprising:
a) one or more sensors configured for emitting and receiving (i) a target signal into tissue at a target location of a subject and (ii) a plurality of non-target signals into non-target tissue locations adjacent to said target location of said subject, b) a circuit electronically coupled to said one or more sensors and configured to convert said target signal into a target SEM value and said plurality of non-target signals into a plurality of non-target SEM values;
c) a processor electronically coupled to said circuit and configured to receive said target SEM value and said plurality of non-target SEM values; and
d) a non-transitory computer readable medium electronically coupled to said processor and comprising instructions stored thereon that when executed on said processor, perform:
i) receiving from said processor said target SEM value, said plurality of non-target SEM values, said target location, and said non-target tissue locations;
ii) determining a) a maximum SEM value and a minimum SEM value from said plurality of non-target SEM values and said target SEM value or b) an average SEM value from said plurality of non-target SEM values and said target SEM value;
iii) determining a difference between a) said maximum SEM value and said minimum SEM value or b) said average SEM value and at least one of said plurality of non-target SEM values or said target SEM value; and
iv) identifying said target location or said non-target locations as having a SEM indicative of tissue damage if said difference is greater than a predetermined threshold.
2. The apparatus of claim 1 , further comprising a substrate, wherein said one or more sensors are embedded on a first side of said substrate.
3. The apparatus of claim 1 , wherein said one or more sensors are configured to conform to a non-planar sensing surface of said subject's skin.
4. The apparatus of claim 1 , wherein said non-target tissue locations are equidistant from said target location.
5. The apparatus of claim 1 , wherein said non-target tissue locations are spaced apart equally from one another.
6. The apparatus of claim 1 , wherein identifying comprises plotting said target SEM value and said plurality of non-target SEM values on a graphical representation of said target location.
7. The apparatus of claim 1 , wherein said target signal and said plurality of non-target signals are received from a target depth within said tissue.
8. The apparatus of claim 7 , wherein said one or more sensors are selected to emit said target signal and said plurality of non-target signals to said target depth.
9. The apparatus of claim 8 , wherein said target depth is selected based on said target location, an age of said subject, or a skin anatomy of said subject.
10. The apparatus of claim 7 , wherein said target depth is at least 0.5 millimeters.
11. The apparatus of claim 7 , wherein said target depth is at least 4 millimeters.
12. The apparatus of claim 1 , wherein said plurality of non-target tissue locations are on one or more concentric circles around said target location.
13. The apparatus of claim 1 , wherein i) through iv) are repeated over a period of time.
14. The apparatus of claim 1 , wherein a shape of said one or more sensors comprise a ring coaxial to at least one sensor.
15. The apparatus of claim 1 , wherein said one or more sensors have a substantially round or elliptic shape.
16. A method comprising:
a) emitting a plurality of first signals into a subject's skin at a target location of said subject's skin and one or more non-target locations adjacent to said target location of said subject's skin;
b) receiving a plurality of second signals derived from said first signals from said subject's skin at said target location and said one or more non-target locations;
c) converting said plurality of second signals into a target sub-epidermal moisture (SEM) value and a plurality of non-target SEM values;
d) determining i) a maximum SEM value and a minimum SEM value from said plurality of non-target SEM values and said target SEM value or ii) an average SEM value from said plurality of non-target SEM values and said target SEM value;
e) determining a difference between i) said maximum SEM value and said minimum SEM value or ii) said average SEM value and at least one of said plurality of non-target SEM values or said target SEM value; and
f) identifying said target location or said one or more non-target locations as having a SEM indicative of tissue damage if said difference is greater than a predetermined threshold.
17. The method of claim 16 , wherein a) through f) are repeated over a period of time.
18. The method of claim 16 , wherein a) and b) are performed using one or more sensors.
19. The method of claim 18 , wherein said one or more sensors are embedded on a first side of a substrate.
20. The method of claim 19 , wherein said substrate is flexible.
21. The method of claim 19 , wherein said substrate is rigid.
22. The method of claim 18 , wherein said one or more sensors are configured to conform to a non-planar sensing surface of said subject's skin.
23. The method of claim 22 , wherein said non-planar sensing surface comprises a body curvature or bony prominence.
24. The method of claim 23 , wherein said bony prominence is a heel, a sternum, sacrum, a scapula, an elbow, or an ear of said subject.
25. The method of claim 16 , further comprising plotting said target SEM value and said plurality of non-target SEM values on a graphical representation of said target location.
26. The method of claim 16 , wherein said one or more non-target locations are equidistant from said target location.
27. The method of claim 16 , wherein said one or more non-target locations are spaced apart equally from one another.
28. The method of claim 18 , wherein said plurality of second signals are received from a target depth within said tissue.
29. The method of claim 28 , further comprising, before a), selecting said one or more sensors to emit said plurality of first signals to said target depth.
30. The method of claim 29 , further comprising selecting said target depth based on said target location, an age of said subject, or a skin anatomy of said subject.