Compression depth feedback and adjustment

A mechanical chest compression device comprising:

• a chest compressing mechanism configured to be disposed on a chest of a subject and to administer chest compressions to the subject;
• and
• a processor configured to:
• receive an indication that the subject has pulseless electrical activity (PEA), refractory ventricular fibrillation (VF), recurrent VF, or asystole;
• and
• in response to receiving the indication that the subject has the PEA, the refractory VF, the recurrent VF, or the asystole, cause the chest compressing mechanism to increase a current target compression depth to an increased target compression depth at which future chest compressions are to be administered to the subject.

A method comprising:

• causing, by a processor, a chest compressing mechanism of a mechanical chest compression device to administer first chest compressions to a subject at a first target compression depth;
• receiving, by the processor, an indication that the subject has pulseless electrical activity (PEA), refractory ventricular fibrillation (VF), recurrent VF, or asystole;
• and
• in response to receiving the indication that the subject has the PEA, the refractory VF, the recurrent VF, or the asystole, causing, by the processor, the chest compressing mechanism to administer second chest compressions to the subject at a second target compression depth greater than the first target compression depth.