A system for assisting with a cardiopulmonary resuscitation (CPR) treatment being administered to a patient. In one aspect, a system for assisting with a cardiopulmonary resuscitation (CPR) treatment being administered to a patient includes a sensor for determining a parameter of the patient (e.g., indicative of a blood flow or pressure waveform), and one or more processors configured for receiving input from the sensor, determining, based on the input from the sensor, whether a rate of chest compressions administered in the CPR treatment should be changed, and providing an indication to a user that the rate of chest compressions should be changed.