Chest compliance directed chest compressions
Among other things, in one aspect, we describe a system for assisting with cardiopulmonary resuscitation (CPR). The system includes at least one sensor; and one or more processors configured for calculating a chest compliance relationship based on data received from the at least one sensor, and determining a neutral position of chest compression based at least in part on a feature of the chest compliance relationship. The system can take the form of an active compression-decompression device.
1. A method for assisting with cardiopulmonary resuscitation (CPR) administered to a patient using an active compression-decompression device, the method comprising:
receiving, from at least one motion sensor and from at least one force sensor, data recorded during administration of active compression-decompressions to the chest of the patient by the active compression-decompression device;
calculating a chest compliance relationship during the active compression-decompressions involving displacement and force based on the data received from the at least one motion sensor and the at least one force sensor;
estimating a neutral position of the chest for a cycle of the active compression-decompressions as the active compression-decompressions of the cycle are administered, the neutral position of the chest being based at least in part on a feature of the chest compliance relationship, wherein the cycle comprises a continuous variation from a non-elevated chest position to an elevated decompressed chest position and the neutral position of the chest corresponds to a transition phase of the cycle of the active compression-decompressions during which the force applied to the chest is substantially zero; and
adjusting one or more application parameters of the active compression-decompression device based on the neutral position of the chest.
2. The method of claim 1 , wherein the one or more application parameters comprise at least one of displacement, velocity, acceleration, time, work, power, pressure, direction and orientation.
3. The method of claim 1 , wherein the one or more application parameters comprise a distance above the neutral position of the chest and a depth of compression below the neutral position of the chest.
4. The method of claim 1 , wherein the chest compliance relationship defines a compliance curve.
5. The method of claim 4 , wherein the compliance curve comprises a hysteresis compliance curve illustrating a chest compliance relative to a chest compression displacement.
6. The method of claim 5 , wherein the feature of the hysteresis compliance curve comprises a point of intersection of subsequent hysteresis compliance curves.
7. The method of claim 4 , wherein the feature of the compliance curve comprises a point approximately halfway between two peaks of two compliance curves.
8. The method of claim 4 , wherein the compliance curve comprises a non-hysteresis compliance curve.
9. The method of claim 4 , wherein the feature comprises a peak of the compliance curve.
10. The method of claim 1 , wherein adjusting one or more application parameters of the active compression-decompression device based on the neutral position of the chest comprises:
increasing the one or more application parameters of the active compression-decompression device, or
decreasing the one or more application parameters of the active compression-decompression device.
11. The method of claim 1 , wherein adjusting one or more application parameters of the active compression-decompression device based on the neutral position of the chest comprises providing an output for a user to adjust the one or more application parameters.
12. The method of claim 1 , wherein the data recorded during administration of the active compression-decompressions to the chest of the patient comprises a pressure measurement.
13. The method of claim 1 , wherein the data recorded during administration of the active compression-decompressions to the chest of the patient comprises a displacement signal.
14. The method of claim 1 , wherein the data recorded during administration of the active compression-decompressions to the chest of the patient comprises information for determining whether at least one transition point of the CPR has been reached.
15. The method of claim 14 , wherein the at least one transition point is at least one of between an elevated compression phase and a non-elevated compression phase, between an elevated decompression phase and the elevated compression phase, between the elevated decompression phase and a hold time above the neutral position of the chest, and between a hold time above the neutral position of the chest and the elevated compression phase.
16. The method of claim 14 , wherein the at least one transition point is at least one of between a non-elevated compression phase and a non-elevated decompression phase, between the non-elevated compression phase and a hold time below the neutral position of the chest, and between hold time below the neutral position of the chest and the non-elevated decompression phase.
17. The method of claim 14 , wherein the at least one transition point is between a non-elevated decompression phase and an elevated decompression phase.
18. The method of claim 1 comprising:
identifying a potential for injury of a patient undergoing CPR, the identification based at least in part on the feature of the chest compliance relationship.
19. The method of claim 18 , wherein a reduction in compliance below a predetermined threshold indicates the potential for injury of the patient undergoing CPR.
20. The method of claim 1 comprising:
applying a negative pressure on the chest of the patient.
21. The method of claim 1 , wherein the neutral position of the chest comprises a first neutral position of the chest corresponding to a first chest compression of the chest that is different from a second neutral position of the chest corresponding to a second chest compression that is subsequent to the first chest compression.
22. A system for assisting with cardiopulmonary resuscitation (CPR), the system comprising:
an active compression-decompression device configured to be affixed to a chest of a patient, the active compression-decompression device being configured to deliver active compression-decompressions to the chest of the patient;
at least one motion sensor operably coupled with the active compression-decompression device;
at least one force sensor operably coupled with the active compression-decompression device; and
one or more processors and a non-transitory computer readable storage medium encoded with a computer program comprising instructions that, when executed, cause the one or more processors to perform operations comprising:
calculating a chest compliance relationship during the active compression-decompressions involving displacement and force based on data received from the at least one motion sensor and the at least one force sensor,
estimating a neutral position of the chest for a cycle of the active compression-decompressions as the active compression-decompressions of the cycle are administered, the neutral position of the chest being based at least in part on a feature of the chest compliance relationship, wherein the cycle comprises a continuous variation from a non-elevated chest position to an elevated decompressed chest position and the neutral position of the chest corresponds to a transition phase of the cycle of the active compression-decompressions during which the force applied to the chest is substantially zero, and
generating an indication to adjust one or more application parameters of the active compression-decompression device based on the neutral position of the chest.
23. The system of claim 22 , wherein the one or more application parameters comprise at least one of displacement, velocity, acceleration, time, work, power, pressure, direction and orientation.
24. The system of claim 22 , wherein the one or more application parameters comprise a distance above the neutral position of the chest and a depth of compression below the neutral position of the chest.
25. The system of claim 22 , wherein the chest compliance relationship defines a compliance curve.
26. The system of claim 25 , wherein the compliance curve comprises a hysteresis compliance curve illustrating a chest compliance relative to a chest compression displacement.
27. The system of claim 26 , wherein a feature of the hysteresis compliance curve comprises a point of intersection of subsequent hysteresis compliance curves.
28. The system of claim 26 , wherein the feature of the compliance curve comprises a point approximately halfway between two peaks of two compliance curves.
29. The system of claim 25 , wherein the compliance curve comprises a non-hysteresis compliance curve.
30. The system of claim 29 , wherein the feature comprises a peak of the non-hysteresis compliance curve.
31. The system of claim 22 , wherein the active compression-decompression device comprises a suction cup and a handle.
32. The system of claim 22 , wherein the at least one force sensor provides an output convertible to a pressure measurement.
33. The system of claim 22 , wherein at least one of the at least one motion sensor and the at least one force sensor are components of the active compression-decompression device.
34. The system of claim 22 , wherein the at least one motion sensor comprises an accelerometer.
35. The system of claim 22 , wherein the at least one motion sensor measures information for determining whether at least one transition point of the CPR has been reached.
36. The system of claim 35 , wherein the at least one transition point is at least one of between an elevated compression phase and a non-elevated compression phase, between an elevated decompression phase and the elevated compression phase, between the elevated decompression phase and a hold time above the neutral position of the chest, and between a hold time above the neutral position of the chest and the elevated compression phase.
37. The system of claim 35 , wherein the at least one transition point is at least one of between a non-elevated compression phase and a non-elevated decompression phase, between the non-elevated compression phase and a hold time below the neutral position of the chest, and between hold time below the neutral position of the chest and the non-elevated decompression phase.
38. The system of claim 35 , wherein the at least one transition point is between a non-elevated decompression phase and an elevated decompression phase.
39. The system of claim 22 , wherein the one or more processors are configured for identifying a potential for injury of a patient undergoing CPR, the identification based at least in part on the feature of the chest compliance relationship.
40. The system of claim 39 , wherein a reduction in compliance below a predetermined threshold indicates the potential for injury of the patient undergoing CPR.
41. The system of claim 22 , wherein the system comprises an impedance threshold device configured to apply negative pressure on the chest of the patient.
42. The system of claim 22 , wherein the system comprises an adhesive pad configured to be adhered to at least a portion of a patient's chest.
43. The system of claim 22 , wherein the neutral position of the chest comprises a first neutral position of the chest corresponding to a first chest compression of the chest that is different from a second neutral position of the chest corresponding to a second chest compression that is subsequent to the first chest compression.
44. A method for assisting with cardiopulmonary resuscitation (CPR) administered to a patient using an active compression-decompression device, the method comprising:
receiving, from at least one motion sensor and from at least one force sensor, data recorded during administration of active compression-decompressions to the chest of the patient by the active compression-decompression device;
calculating a chest compliance relationship during the active compression-decompressions involving displacement and force based on the data received from the at least one motion sensor and the at least one force sensor;
estimating a neutral position of the chest for a cycle of the active compression-decompressions as the active compression-decompressions of the cycle are administered, the cycle comprising a continuous variation from a non-elevated chest position to an elevated compressed chest position, the neutral position of the chest being based at least in part on a feature of the chest compliance relationship; and
adjusting one or more application parameters of the active compression-decompression device based on the neutral position of the chest.
45. The method of claim 44 , wherein the one or more application parameters comprise at least one of displacement, velocity, acceleration, time, work, power, pressure, direction orientation, and a distance above the neutral position of the chest and a depth of compression below the neutral position of the chest.
46. The method of claim 44 , wherein the chest compliance relationship defines a compliance curve.
47. The method of claim 46 , wherein the compliance curve comprises a hysteresis compliance curve illustrating a chest compliance relative to a chest compression displacement, wherein the feature of the hysteresis compliance curve comprises a point of intersection of subsequent hysteresis compliance curves.
48. The method of claim 46 , wherein the feature of the compliance curve comprises a point approximately halfway between two peaks of two compliance curves.
49. The method of claim 46 , wherein the compliance curve comprises a non-hysteresis compliance curve.
50. The method of claim 49 , wherein the feature comprises a peak of the compliance curve.
51. The method of claim 44 , wherein adjusting one or more application parameters of the active compression-decompression device based on the neutral position of the chest comprises:
increasing the one or more application parameters of the active compression-decompression device, or
decreasing the one or more application parameters of the active compression-decompression device.
52. The method of claim 44 , wherein adjusting one or more application parameters of the active compression-decompression device based on the neutral position of the chest comprises providing an output for a user to adjust the one or more application parameters.
53. The method of claim 44 , wherein the data recorded during administration of the active compression-decompressions to the chest of the patient comprises a pressure measurement or a displacement signal.
54. The method of claim 44 , wherein the data recorded during administration of the active compression-decompressions to the chest of the patient comprises information for determining whether at least one transition point of the CPR has been reached.
55. The method of claim 54 , wherein the at least one transition point is at least one of between an elevated compression phase and a non-elevated compression phase, between an elevated decompression phase and the elevated compression phase, between the elevated decompression phase and a hold time above the neutral position of the chest, and between a hold time above the neutral position of the chest and the elevated compression phase.
56. The method of claim 54 , wherein the at least one transition point is at least one of between a non-elevated compression phase and a non-elevated decompression phase, between the non-elevated compression phase and a hold time below the neutral position of the chest, and between hold time below the neutral position of the chest and the non-elevated decompression phase.
57. The method of claim 54 , wherein the at least one transition point is between a non-elevated decompression phase and an elevated decompression phase.
58. The method of claim 44 comprising:
identifying a potential for injury of a patient undergoing CPR, the identification based at least in part on the feature of the chest compliance relationship, wherein a reduction in compliance below a predetermined threshold indicates the potential for injury of the patient undergoing CPR.
59. The method of claim 44 comprising:
applying a negative pressure on the chest of the patient.
60. The method of claim 44 , wherein the neutral position of the chest comprises a first neutral position of the chest corresponding to a first chest compression of the chest that is different from a second neutral position of the chest corresponding to a second chest compression that is subsequent to the first chest compression.
61. A system for assisting with cardiopulmonary resuscitation (CPR), the system comprising:
an active compression-decompression device configured to be affixed to a chest of a patient, the active compression-decompression device being configured to deliver active compression-decompressions to the chest of the patient;
at least one motion sensor operably coupled with the active compression-decompression device;
at least one force sensor operably coupled with the active compression-decompression device; and
one or more processors and a non-transitory computer readable storage medium encoded with a computer program comprising instructions that, when executed, cause the one or more processors to perform operations comprising:
calculating a chest compliance relationship during the active compression-decompressions involving displacement and force based on data received from the at least one motion sensor and the at least one force sensor,
estimating a neutral position of the chest for a cycle of the active compression-decompressions as the active compression-decompressions of the cycle are administered, wherein the cycle comprises a continuous variation from a non-elevated chest position to an elevated decompressed chest position, the neutral position of the chest being based at least in part on a feature of the chest compliance relationship, and
generating an indicator to adjust one or more application parameters of the active compression-decompression device based on the neutral position of the chest.
62. The system of claim 61 , wherein the one or more application parameters comprise at least one of displacement, velocity, acceleration, time, work, power, pressure, direction orientation, and a distance above the neutral position of the chest and a depth of compression below the neutral position of the chest.
63. The system of claim 61 , wherein the chest compliance relationship defines a compliance curve or a hysteresis compliance curve illustrating a chest compliance relative to a chest compression displacement.
64. The system of claim 63 , wherein a feature of the hysteresis compliance curve comprises a first point of intersection of subsequent hysteresis compliance curves or a second point approximately halfway between two peaks of two compliance curves.
65. The system of claim 63 , wherein the compliance curve comprises a non-hysteresis compliance curve, wherein the feature comprises a peak of the non-hysteresis compliance curve.
66. The system of claim 61 , wherein the active compression-decompression device comprises a suction cup and a handle.
67. The system of claim 61 , wherein the at least one force sensor provides an output convertible to a pressure measurement.
68. The system of claim 61 , wherein at least one of the at least one motion sensor and the at least one force sensor are components of the active compression-decompression device.
69. The system of claim 61 , wherein the at least one motion sensor comprises an accelerometer that measures information for determining whether at least one transition point of the CPR has been reached.
70. The system of claim 69 , wherein the at least one transition point is at least one of between an elevated compression phase and a non-elevated compression phase, between an elevated decompression phase and the elevated compression phase, between the elevated decompression phase and a hold time above the neutral position of the chest, and between a hold time above the neutral position of the chest and the elevated compression phase.
71. The system of claim 70 , wherein the at least one transition point is at least one of between a non-elevated compression phase and a non-elevated decompression phase, between the non-elevated compression phase and a hold time below the neutral position of the chest, and between hold time below the neutral position of the chest and the non-elevated decompression phase.
72. The system of claim 70 , wherein the at least one transition point is between a non-elevated decompression phase and an elevated decompression phase.
73. The system of claim 61 , wherein the one or more processors are configured for identifying a potential for injury of a patient undergoing CPR, the identification based at least in part on the feature of the chest compliance relationship, wherein a reduction in compliance below a predetermined threshold indicates the potential for injury of the patient undergoing CPR.
74. The system of claim 61 , wherein the system comprises an impedance threshold device configured to apply negative pressure on the chest of the patient and an adhesive pad configured to be adhered to at least a portion of a patient's chest.
75. The system of claim 61 , wherein the neutral position of the chest comprises a first neutral position of the chest corresponding to a first chest compression of the chest that is different from a second neutral position of the chest corresponding to a second chest compression that is subsequent to the first chest compression.