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 providing cardiopulmonary resuscitation (CPR) to a patient using an active compression-decompression device, the method comprising:
administering active compression-decompression CPR to the patient's chest using the active compression-decompression device;
receiving force data from at least one force sensor provided with the active compression-decompression device;
determining an instantaneous chest compliance value at a particular time during continuous administration of active compression-decompressions based on the received force data, wherein the instantaneous chest compliance value comprises a mathematical relationship expressing a change of displacement of the patient's chest between the particular time and a reference time and a change in determined force at the particular time and at the reference time, wherein the determined force is based on the received force data; and
adjusting one or more CPR parameters of the administered active compression-decompressions based on the instantaneous chest compliance value during continuous administration of active compression-decompressions.
2. The method of claim 1 , wherein the administered active compression-decompressions comprise continuous variation from compressions associated with a non-elevated chest position and decompressions associated with an elevated decompressed chest position.
3. The method of claim 1 , comprising:
determining a plurality of instantaneous chest compliance values for a plurality of time points; and
generating a chest compliance relationship based on a compliance curve comprising the plurality of instantaneous chest compliance values.
4. The method of claim 3 , wherein the compliance curve comprises a hysteresis compliance curve indicative of a chest compliance relative to chest compression displacement.
5. The method of claim 3 , wherein the compliance curve comprises a non-hysteresis compliance curve.
6. The method of claim 1 , comprising:
determining an absolute compliance based on chest compression displacement at a peak of the compression relative to a pressure at the peak of the compression; and
generating the chest compliance relationship based on the absolute compliance.
7. The method of claim 1 , wherein the one or more CPR parameters comprise a distance of chest elevations and a depth of chest compressions.
8. The method of claim 1 , wherein adjusting the one or more CPR parameters comprises increasing the one or more CPR parameters of the active compression-decompression device, or decreasing the one or more CPR parameters of the active compression-decompression device.
9. The method of claim 8 , wherein adjusting the one or more CPR parameters of the active compression-decompression device comprises providing an output for a user to adjust one or more application parameters for administration of active compression-decompression.
10. The method of claim 1 , wherein the force data recorded during administration of the active compression-decompressions to the chest of the patient comprises at least one of: a pressure measurement, and a displacement signal.
11. The method of claim 1 , wherein the force 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.
12. The method of claim 11 , wherein the at least one transition point is at least one of: between an elevated compression phase and a non-elevated compression phase, or between an elevated decompression phase and the elevated compression phase.
13. The method of claim 12 , wherein the at least one transition point is at least one of between a non-elevated compression phase and a non-elevated decompression phase, or between a non-elevated decompression phase and an elevated decompression phase.
14. The method of claim 1 , comprising:
identifying a potential for injury of a patient undergoing CPR, the identification being based at least in part on the chest compliance relationship.
15. The method of claim 14 , wherein a reduction in compliance below a predetermined threshold indicates the potential for injury of the patient undergoing CPR.
16. The method of claim 1 comprising:
applying a negative pressure on the chest of the patient.
17. The method of claim 1 , wherein continuous administration comprises administering the active compression-decompression CPR to the patient's chest using the active-decompression device comprising compressions associated with a non-elevated chest position and decompressions associated with an elevated decompressed chest position.
18. The method of claim 17 , wherein continuous administration comprises administering the active compression-decompression CPR to the patient's chest using the active-decompression device comprising ongoing compressions associated with a non-elevated chest position and decompressions associated with an elevated decompressed chest position.
19. A system for providing cardiopulmonary resuscitation (CPR) to a patient, 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 force sensor operably coupled with the active compression-decompression device configured to detect force data; 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:
receiving force data from the at least one force sensor provided with the active compression-decompression device,
determining an instantaneous chest compliance value at a particular time during continuous administration of active compression-decompressions based on the received force data, wherein the instantaneous chest compliance value comprises a mathematical relationship expressing a change of displacement of the patient's chest between the particular time and a reference time and a change in determined force at the particular time and at the reference time, wherein the determined force is based on the received force data, and
generating an indication to adjust one or more CPR parameters of the delivered active compression-decompressions based on the instantaneous chest compliance value during continuous administration of active compression-decompressions.
20. The system of claim 19 , wherein a chest compliance relationship defines a compliance curve comprising a plurality of instantaneous compliance values corresponding to a plurality of time points.
21. The system of claim 20 , wherein the compliance curve comprises a hysteresis compliance curve illustrating a chest compliance relative to a chest compression displacement.
22. The system of claim 20 , wherein the compliance curve comprises a non-hysteresis compliance curve.
23. The system of claim 19 , wherein the chest compliance relationship defines a compliance curve comprising an absolute compliance based on a displacement at a peak of the compression relative to a pressure at the peak of the compression.
24. The system of claim 19 , wherein the one or more CPR parameters comprise at least one of displacement, velocity, acceleration, time, work, power, pressure, direction and orientation.
25. The system of claim 19 , wherein the active compression-decompression device comprises a suction cup.
26. The system of claim 19 , wherein the at least one force sensor provides an output convertible to a pressure measurement.
27. The system of claim 19 , wherein the at least one force sensor is a component of the active compression-decompression device.
28. The system of claim 19 , wherein the active compression-decompression device comprises an accelerometer.
29. The system of claim 19 , wherein the one or more processors are configured to determine whether at least one transition point of the CPR has been reached.
30. The system of claim 29 , wherein the at least one transition point is at least one of: between an elevated compression phase and a non-elevated compression phase and between an elevated decompression phase and the elevated compression phase.
31. The system of claim 30 , wherein the at least one transition point is at least one of: between a non-elevated compression phase and a non-elevated decompression phase and between the non-elevated compression phase, or between a non-elevated decompression phase and an elevated decompression phase.
32. The system of claim 19 , 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 chest compliance relationship.
33. The system of claim 32 , wherein a reduction in compliance below a predetermined threshold indicates the potential for injury of the patient undergoing CPR.
34. The system of claim 19 , wherein the system comprises an impedance threshold device configured to apply negative pressure on the chest of the patient.
35. The system of claim 19 , wherein the system comprises an adhesive pad configured to be adhered to at least a portion of a patient's chest.
36. The system of claim 19 , wherein continuous administration comprises administering the active compression-decompression CPR to the patient's chest using the active-decompression device comprising compressions associated with a non-elevated chest position and decompressions associated with an elevated decompressed chest position.
37. The system of claim 36 , wherein continuous administration comprises administering the active compression-decompression CPR to the patient's chest using the active-decompression device comprising ongoing compressions associated with a non-elevated chest position and decompressions associated with an elevated decompressed chest position.