Sensor for foetal monitoring
A sensor for foetal monitoring, in particular for measuring electrophysiological signals, e.g. electrical activity of the uterus of a pregnant woman and/or of the heart of a foetus. The sensor includes a plurality of signal electrodes and a ground electrode mounted in or on a substrate, and a connector for connecting the sensor to a monitoring system. The ground electrode is positioned about or between a pair of signal electrodes.
1. A sensor for foetal monitoring comprising:
a substrate,
a plurality of signal electrodes mounted in or on the substrate, each said signal electrode having an effective diameter of at least 25 mm,
a ground electrode mounted in or on the substrate and positioned about or between a pair of the signal electrodes, and
a connector configured for connecting the signal electrodes of the sensor to a monitoring system.
2. The sensor for foetal monitoring according to claim 1 , wherein the sensor is configured for measuring electrophysio logical signals.
3. The sensor for foetal monitoring according to claim 2 , wherein the sensor is further configured for measuring electrical activity of a uterus of a pregnant woman and/or of a heart of a foetus.
4. The sensor according to claim 2 , wherein a center of the ground electrode and centers of the pair of signal electrodes are positioned on an imaginary line.
5. The sensor according to claim 4 , wherein the signal electrodes and the ground electrode are symmetrical about an imaginary line perpendicular to an imaginary line through the centers of the pair of signal electrodes and the center of the ground electrode and/or symmetrical about an imaginary line through the centers of the pair of signal electrodes and the center of the ground electrode.
6. The sensor according to claim 2 , wherein the connector extends at an angle α to an imaginary line through centers of the pair of the signal electrodes and a center of the ground electrode, and wherein the angle α is in a range of from 70° to 110°.
7. The sensor according to claim 6 , wherein the angle α is in a range of from 80° to 100°.
8. The sensor according to claim 6 , wherein the angle α is about 90°.
9. The sensor according to claim 2 , wherein a distance from a center of a first of the pair of the signal electrodes to a center of second of the pair signal electrodes is in a range of from 70 to 110 mm.
10. The sensor according to claim 9 , wherein the distance is in a range of from 80 to 100 mm.
11. The sensor according to claim 9 , wherein the distance is in a range of from 85 to 95 mm.
12. The sensor according to claim 2 , wherein the signal electrodes have an effective diameter in a range of from 25 to 40 mm.
13. The sensor according to claim 2 , wherein the signal electrodes have an effective diameter in a range of from 28 to 37 mm.
14. The sensor according to claim 2 , wherein the signal electrodes have an effective diameter in a range of from 30 to 35 mm.
15. The sensor according to claim 2 , wherein a surface area of the ground electrode is at least twice a surface area of at least one of the signal electrodes.
16. The sensor according to claim 2 , wherein a surface area of the ground electrode is at least twice a combined surface area of at least two of the signal electrodes.
17. The sensor according to claim 2 , wherein a surface area of the ground electrode is at least twice a combined surface area of all of the signal electrodes.
18. The sensor according to claim 2 , wherein the ground electrode has an effective diameter in a range of from 30 to 60 mm.
19. The sensor according to claim 2 , wherein the ground electrode has an effective diameter in a range of from 35 to 55 mm.
20. The sensor according to claim 2 , wherein the ground electrode has an effective diameter in a range of from 30 to 50 mm.
21. The sensor according to claim 2 , wherein the sensor is disposable.
22. The sensor according to claim 2 , further comprising a memory that is connected to the connector so as to be accessible via the connector.
23. The sensor according to claim 2 , having exactly one ground electrode and exactly two signal electrodes.
24. The sensor according to claim 2 , wherein the signal electrodes are circular and the ground electrode is between the pair of signal electrodes, the ground electrode is substantially circular and the ground electrode is provided with recesses on opposite sides of the ground electrode to provide sufficient isolation between the ground electrode and the signal electrodes.
25. A system for processing electrophysiological signals comprising:
a sensor according to claim 2 and
a processing unit operatively associated with said sensor for receiving and processing signals from said sensor.
26. A system according to claim 25 , further comprising a presentation device operatively associated with the processing unit for presenting output from said processing unit.
27. A system according to claim 25 , wherein said electrophysiological signals are electrical activity of a uterus of a pregnant woman and/or of a heart of a foetus.
28. A method of foetal monitoring by measuring electrophysiological signals comprising steps of:
preparing a sensor placement site at an abdomen of a pregnant woman, and
placing, at said sensor placement site, a sensor according to claim 2 .
29. The method according to claim 28 , wherein the electrophysiological signals are electrical activity of the uterus of a pregnant woman and/or of a heart of a foetus.
30. The method according to claim 28 , wherein the sensor placement site is prepared by means of an abrasive.
31. The method according to claim 30 , wherein the abrasive is an abrasive tape.