Abstract: 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.