Systems and methods for determining compression depth and providing feedback during active compression decompressions
A system for assisting with cardiopulmonary resuscitation (CPR) includes an active compression decompression (ACD) device configured for a user to push downward and pull upward on a chest of a patient, a sensor to measure force applied to the chest of the patient, a sensor configured to measure displacement of the chest of the patient, one or more processors, and a user interface. The processor is configured to configured to execute computer-executable instructions to determine a maximum compression force applied to the chest of the patient during a compression cycle and a maximum decompression force applied to the chest of the patient during the compression cycle, estimate a displacement value for a total displacement of the chest of the patient during the compression cycle for compressing and decompressing the chest of the patient, and estimate at least one of a compression depth and a decompression displacement for the compression cycle.
1 . A system for assisting with cardiopulmonary resuscitation (CPR), the system comprising:
an active compression decompression (ACD) device configured to push downward and pull upward on a chest of a patient;
a force sensor configured to measure force applied to the chest of the patient by the ACD device;
a motion sensor configured to measure displacement of the chest of the patient;
one or more computer-readable media storing computer-executable instructions; and
one or more processors configured to execute the computer-executable instructions, the execution carrying out operations to:
identify, based on one or more signals received from at least one of the force sensor and the motion sensor, a compression cycle for an active compression decompression treatment, wherein the compression cycle comprises a compression phase and a decompression phase,
determine a first displacement of chest compression corresponding to a crossing point in a force-displacement relationship of the compression phase of the compression cycle,
determine a second displacement of chest compression corresponding to crossing point in a force-displacement relationship of the decompression phase of the compression cycle,
estimate a neutral position of the chest of the patient based on the first displacement and the second displacement for each identified compression cycle of the active compression decompression treatment;
generate at least one feedback signal based on the estimated neutral position; and
modify operation of the ACD device based on the generated at least one feedback signal.
2 . The system of claim 1 , wherein estimating the neutral position of the chest of the patient based on the first displacement and the second displacement comprises determining a chest compression displacement representing the neutral position of the chest that is inside a range defined by the first displacement and the second displacement.
3 . The system of claim 1 , wherein estimating the neutral position of the chest of the patient based on the first displacement and the second displacement comprises determining a chest compression displacement representing the neutral position of the chest that is outside a range defined by the first displacement and the second displacement.
4 . The system of claim 1 , wherein estimating the neutral position of the chest of the patient based on the first displacement and the second displacement comprises determining a chest compression displacement representing the neutral position of the chest that is a function of an average of the first displacement and the second displacement.
5 . The system of claim 4 , wherein the function of the average of the first displacement and the second displacement comprises a moving average of the first displacement and the second displacement for a plurality of compression cycles including the compression cycle and one or more compression cycles immediately prior to the compression cycle.
6 . The system of claim 1 , wherein estimating the neutral position of the chest of the patient based on the first displacement and the second displacement comprises determining a chest compression displacement representing the neutral position of the chest that is a function of the first displacement and the second displacement, wherein the first displacement is weighted by a first weight value and wherein the second displacement is weighted by a second weight value that is different than the first weight value.
7 . The system of claim 1 , wherein the compression phase comprises at least one of a compression elevated portion and a compression non-elevated portion.
8 . The system of claim 1 , wherein the decompression phase comprises at least one of a decompression elevated portion and decompression non-elevated portion.
9 . The system of claim 1 , wherein the force-displacement relationship of the compression phase is different than the force-displacement relationship of the decompression phase based on a hysteresis of the compression cycle.
10 . The system of claim 1 , wherein the ACD device comprises:
a first element configured to be coupled to the chest of the patient; and
a second element configured to be grasped by a rescuer, the second element being coupled to the first element.
11 . The system of claim 1 , wherein the ACD device comprises at least one of the force sensor and the motion sensor.
12 . The system of claim 1 , wherein the motion sensor comprises an accelerometer.
13 . The system of claim 1 , comprising a user interface configured to display data representing one or more of the first displacement and the second displacement.
14 . The system of claim 13 , wherein the user interface is configured to display data indicating one or more of the force and the displacement.
15 . The system of claim 13 , wherein the user interface is configured to display a compression non-elevated depth of the compression phase.
16 . The system of claim 13 , wherein the user interface is configured to display a decompression elevated height of the decompression phase.
17 . The system of claim 13 , wherein the user interface is configured to display a trend graph representing chest remodeling.
18 . The system of claim 13 , wherein the user interface is configured for display on a device that is external to the ACD device.
19 . The system of claim 18 , wherein the device is remote from the ACD device.
20 . The system of claim 18 , wherein the device comprises at least one of a smartphone, a smartwatch, and a tablet device.
21 . The system of claim 1 , comprising a communication device configured to communicate data to an external device and receive data from the external device.
22 . The system of claim 1 , wherein the execution is carrying out operations to:
determine a third displacement of chest compression corresponding to when approximately zero force is applied to the chest of the patient during the compression phase of the compression cycle,
determine a fourth displacement of chest compression corresponding to when approximately zero force is applied to the chest of the patient during the decompression phase of the compression cycle, and
estimate the neutral position of the chest of the patient based on the first displacement, the second displacement, the third displacement and the fourth displacement.
23 . The system of claim 22 , wherein the execution is carrying out operations to:
determine a fifth displacement of chest compression corresponding to a first product of force and displacement on the compression phase of the compression cycle,
determine a sixth displacement of chest compression corresponding to a second product of force and displacement on the decompression phase of the compression cycle, and
estimate the neutral position of the chest of the patient based on the first displacement, the second displacement, the third displacement, the fourth displacement, the fifth displacement, and the displacement depth.
24 . The system of claim 23 , wherein estimating the neutral position of the chest of the patient based on the first displacement, the second displacement, the third displacement, the fourth displacement, the fifth displacement, and the sixth displacement comprises a function of an average of the first displacement, the second displacement, the third displacement, the fourth displacement, the fifth displacement, and the sixth displacement.