Systems and methods for determining compression depth and providing feedback during active compression decompressions

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.