METHOD AND APPARATUS FOR MONITORING MANUAL CHEST COMPRESSION EFFICIENTLY DURING CPR

Abstract

A compression measurement and feedback system which measures the magnitude and the angle of manual CPR force applied to a patient and provides the measured magnitude and direction information as compression data feedback to the person applying CPR to the patient. Any variation in the magnitude or direction of the compression force applied may be calculated from the compression data measured by the compression sensor. A monitor receives the compression data and processes the compression data to generate feedback data to the CPR provider indicating the magnitude and direction of the applied CPR compression along with ideal CPR compression characteristics for comparison.

Claims

1-15. (canceled)

16. A CPR compression measurement and feedback system, comprising: a compression sensor for measuring a magnitude and a direction of CPR compression force applied to a patient undergoing CPR and for providing, as compression data, the measured magnitude and the measured direction; and a monitor for receiving and processing the compression data, the monitor configured to: based on the compression data, calculate a variation in the magnitude and a variation in the direction of the applied CPR compression force from desired CPR compression characteristics, and based on the calculated variation in the magnitude and the calculated variation in the direction, generate feedback, for a CPR provider, to indicate the measured magnitude and the measured direction of the applied CPR compression force and to indicate the calculated variation in the magnitude and calculated variation in the direction of the applied CPR compression force from the desired CPR compression characteristics.

17. The system of claim 16, wherein the monitor is configured to generate the feedback, wherein the feedback indicates the calculated variation in the magnitude of the applied CPR compression force relative to a desired magnitude of CPR compression force.

18. The system of claim 17, wherein the monitor is configured to generate the feedback comprising an indication, of the calculated variation in the magnitude of the applied CPR compression force relative to the desired magnitude of CPR compression force, that varies with an extent of the calculated variation in the magnitude of the applied CPR compression force relative to the desired magnitude of CPR compression force.

19. The system of claim 18, wherein the monitor is configured to generate the feedback, wherein the feedback comprises visual feedback.

20. The system of claim 16, wherein the monitor is configured to generate the feedback, wherein the feedback indicates the calculated variation in the direction of the applied CPR compression force, relative to a desired direction of CPR compression force, associated with each of two orthogonal horizontal axes, the two orthogonal horizontal axes being horizontal relative to the patient.

21. The system of claim 20, wherein the monitor is configured to generate the feedback comprising an indication, of the calculated variation in the direction of the applied CPR compression force relative to the desired direction of CPR compression force, that varies with an extent of the calculated variation in the direction of the applied CPR compression force relative to the desired direction of CPR compression force.

22. The system of claim 21, wherein the monitor is configured to generate the feedback, wherein the feedback comprises visual feedback.

23. The system of claim 20, wherein the monitor is configured to generate the feedback, wherein the desired direction of CPR compression force is along an anterior-posterior axis of the patient, and wherein the variation is along each of the two orthogonal horizontal axes and relative to the anterior-posterior axis of the patient.

24. The system of claim 23, wherein the monitor is configured to generate the feedback, wherein the two orthogonal horizontal axes comprise a lateral axis relative to the patient and a superior-inferior axis relative to the patient.

25. The system of claim 16, wherein the compression sensor comprises at least one magnet.

26. The system of claim 25, wherein the at least one magnet comprises at least one permanent magnet.

27. The system of claim 25, wherein the compression sensor comprises an array of magnetic sensors.

28. The system of claim 27, wherein the compression sensor comprises: a printed circuit board comprising the array of magnetic sensors; and a compression pad secured to the printed circuit board, the compression pad comprising the at least one magnet.

29. The system of claim 28, wherein the compression pad is a polymer compression pad.

30. The system of claim 28, wherein the at least one magnet is suspended above the array of magnetic sensors.

31. The system of claim 30, wherein the at least one magnet is disposed within the compression pad.

32. The system of claim 31, comprising the array of magnetic sensors, wherein applied force to the compression pad causes movement of the at least one magnet relative to the array of magnetic sensors.

33. The system of claim 32, comprising the array of magnetic sensors, wherein the movement of the at least one magnet relative to the array of magnetic sensors is a function of a magnitude and a direction of the applied force to the compression pad.

34. The system of claim 33, comprising the at least one magnet, wherein, prior to the applied force to the compression pad, the at least one magnet is centered along an anterior-superior axis, relative to the patient, that corresponds to a line between a spine of the patient and a sternum of the patient, the line passing through a heart of the patient.

35. The system of claim 34, comprising the array of magnetic sensors, wherein the array of magnetic sensors are positioned around the anterior-superior axis.

36. The system of claim 35, comprising the array of magnetic sensors, wherein the applied force to the compression pad causes displacement of magnetic field components relative to prior to the applied force to the compression pad, wherein the displacement is measured by the array of magnetic sensors, wherein the displacement is a function of the magnitude and the direction of the applied force to the compression pad.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1 is a perspective view of a CPR provider performing CPR on a victim with a compression sensor and feedback display.

[0018] FIG. 2 is a representation of a graphical user interface for providing CPR feedback.

[0019] FIG. 3 is a perspective view of a CPR provider performing CPR on a victim illustrating the reference axes.

[0020] FIG. 4 is a perspective view of the reference axes illustrating compression measurement elements.

[0021] FIG. 5 is a perspective view of a compression sensor with strain gauges.

[0022] FIG. 6 is a perspective view of a compression sensor with a magnet, and magnetic field sensors.

[0023] FIG. 7 is a perspective view of a compression sensor with capacitive sensors.

[0024] FIG. 8 is a perspective view of a compression sensor with a reflector and light sensor arrays.

DETAILED DESCRIPTION OF THE INVENTIONS

[0025] FIG. 1 illustrates cardiac arrest victim 2 receiving CPR from CPR provider 3 using compression measurement and feedback system 10. CPR provider 3 performs manual CPR by applying compression force to compression sensor 12. Signals such as signals 13 representing the magnitude and direction of compression force 15 are transmitted to a coupled AED, monitor, monitor/defibrillator or other suitable apparatus such as AED monitor 16. Signals 13, representing the applied compression force and any other suitable signals may be transmitted to AED 16 using wires, wireless system and use any suitable communications protocol. Monitor 16 receives signals 13 from compression sensor 12 and processes the signals and generates one or more audible and or visual cues such as feedback display 18 to prompt provider 3 to optimize compression force 15 and angle of application to improve the application of manual CPR and to provide more consistent application of manual CPR.

[0026] Referring now to FIG. 3, during the practice of manual CPR, a CPR provider such as CPR provider 3 repeatedly applies compression force 15 to the victims chest. Ideally, a CPR compression force is a vector 15 applied along the Z-axis which, corresponds to a line drawn between the victims spine and the sternum which includes the heart. When a CPR provider is inexperienced, stressed or tired they tend to apply compression force at an angle with a significant wasted horizontal force. By applying compression force at an angle off the vertical axis, the magnitude of the useful force along the vertical or Z-axis is less than ideal.

[0027] Referring now to FIG. 4, first angle 19 represents the angular deviation of compression force 15 along the X-axis, the lateral axis of the patient, and second angle 20 represents the angular deviation of compression force 15 along the Y-axis, the superior-inferior axis of the patient.

[0028] Compression sensor 22 of FIG. 5 includes polymer compression pad 24 formed on or secured to printed circuit board 25 (PCB). Polymer compression pads such as compression pad 24 may adopt a disk shape, a dome shape or any other suitable shape. Circuit board 25 is a generally planar disk Perpendicular to the Z-axis or central axis 28 and it includes one or more strain gauge sensors such as sensor 27 formed in or on the printed circuit board. The sensors are arranged around central axis such that when a compression force such as force 29 is applied to compression sensor 22, variations in the force registered by different sensors around central axis 28 may be used to determine the magnitude and direction of force 29. Any angular deviation of force 29 from the Z-axis or central axis 28 is provided to a CPR provider in the form of audible of visual feedback to prompt the CPR provider to properly orient the compression force and optimize the magnitude of the compression force.

[0029] Compression data 30 is conducted from compression sensor 22 using multi-conductor cable 31 to any suitable AED, monitor, monitor/defibrillator or other suitable apparatus such as AES 16 of FIG. 1. Compression data 30 may be transferred via cable such as cable 31 or wirelessly.

[0030] Printed circuit board 25 may also include one or more slots, cuts or other points of flexibility such as slots 34 to enable limited flexure of the printed circuit board during CPR. Printed circuit board 25 and mechanical layer 32 may also be shaped to conform to the shape of a human sternum to minimize mechanical flexure during the application of CPR compressions. One or more additional layers such as mechanical layer 32 may be bonded to printed circuit board 25 to provide additional mechanical strength to the printed circuit board. The one or more mechanical layers and the printed circuit board are all generally planar and are generally oriented in the plane formed by the X-axis and the Y-axis and are thus perpendicular to the Z or central axis. Polymer disk 24 is formed of any suitable Polymer or polymer foam with a known compressibility.

[0031] Referring now to FIG. 6, compression sensor 40 includes polymer dome 41 secured to printed circuit board 42. Polymer disk 41 includes permanent magnet 43 embedded in the polymer at a distance H from sensor surface 428 and centered on Z-axis or central axis 44. Printed circuit board 42 includes an array of magnetic sensors such as sensors 45A, 45B and 45C oriented around central axis 44. As a compression force is applied to polymer dome 41, the polymer dome is compressed and magnet 43 is forced closer to printed circuit, board 42 and magnetic sensors 45A, 45B and 45C. Any application of compression force oriented off axis from central or Z-axis 44 will result in variations in compression sensor data 46 from the magnetic sensors. Compression sensor data 46 is conducted to transmitter 47 where the compression sensor data is transmitted to any suitable AED, monitor, monitor/defibrillator or other suitable apparatus such as AED 16 of FIG. 1 for processing and presentation as feedback display 18.

[0032] In use, a compression sensor such as compression sensor 40 is placed on a patient's sternum at the point where manual CPR force is to be applied. The provider of manual CPR places their hands on the compression sensor and applies force to the compression sensor as shown in FIG. 1. The force applied to the compression sensor is transferred through the compression sensor to the patient's sternum, compressing the heart. The compression sensor gathers compression data corresponding to the magnitude and direction of the force applied. The compression data is transferred to a suitable monitor for processing and display of the feedback signals to the CPR provider. Any variation in the magnitude or direction of the force applied may be calculated from the compression data measured by the compression sensor and the variations are presented to the CPR provider as feedback to optimize the compression magnitude and directions

[0033] Referring now to FIG. 2, a graphical user interface to provide feedback to a CPR provider may include a circle or other suitable shape to represent an ideal complete compression such as circle 48. Within the ideal compression circle is a small filled bubble or other shape such as bubble 49 representing the applied compression force. As a CPR compression is applied, the bubble 49 expands as illustrated by bubbles 49A and 49B according to the compression data processed by the monitor. To provide feedback on the direction of the applied compression, bubble 49 may move within the ideal compression circle. Alternatively, a small crosshair or other suitable marker such as crosshair 50 represents the center of the applied compression force and crosshair 50 is moved relative to the ideal compression circle according to the compression data.

[0034] In use, the PCB disk such as disk 42 is generally placed in contact with the patient's chest and the CPR provider applies force to the polymer compression pad for application of CPR. However, the compression sensor may be oriented with the polymer compression pad in contact with the patient's chest and the CPR provider's hands provide force directly to the PCB disk.

[0035] Referring now to FIG. 7, compression sensor 60 includes polymer disk 61 bonded to sensor surface 628 of printed circuit board 62. Sensor surface 62S includes capacitive plate arrays 63 for measuring magnitude and direction of a CPR compression applied to upper surface 64 generally along central or Z-axis 65. Conductive layer 66 is secured over polymer disk 61 with polymer disk 61 between capacitive plate arrays 63 and conductive layer 66. Capacitive plate arrays 63 are generally annual arc shaped and are arranged around central axis 65. In use, capacitive plate arrays 63 are scanned and the parasitic capacitance changes as conductive layer 66 is compressed closer to printed circuit board 62. Depending on the magnitude and direction of the applied compression force, the parasitic capacitance will change in different capacitive plate arrays producing compression data 67 corresponding to the magnitude and direction of the applied compression force.

[0036] Referring now to FIG. 8, illuminated compression sensor 70 includes polymer shell 72, bonded to, secured to or otherwise engaging printed circuit board 73 and enclosing interior volume 74. Interior volume 74 may be filled with any material having light transmission characteristics suitable to enable light 75L emitted from light source 75 along central axis 76 to reflect from reflector 77 and be received by light sensor arrays such as light sensor arrays 78. Compression force applied to outer surface 72X that has any lateral component will cause reflector 77 to reflect light 75L disproportionately to light sensor arrays 78 which will yield direction data and the relative intensity of light reflected to all the light sensor arrays will be proportional to the magnitude of compression force applied to the compression sensor. Collectively the magnitude and direction information will be transmitted as compression data. Each light sensor array generates compression data 79 which may be collected by data unit 80 which formats the compression data for wireless or wired transmission to a monitor for processing and display. Light source 75 may be any suitable source of electromagnetic energy such as an LED or solid state laser.

[0037] While the preferred embodiments of the devices and methods have been described in reference to the environment in which they were developed, they are merely illustrative of the principles of the inventions. The elements of the various embodiments may be incorporated into each of the other species to obtain the benefits of those elements in combination with such other species, and the various beneficial features may be employed in embodiments alone or in combination with each other. Other embodiments and configurations may be devised without departing from, the spirit of the inventions and the scope of the appended claims.