In embodiments, a CPR chest compression system includes a retention structure that can retain the patient's body, and a compression mechanism that can perform automatically CPR compressions and releases to the patient's chest. The compression mechanism can pause the performing of the CPR compressions for a short time, so that an attendant can check the patient. The CPR system can include a user interface that can output a human-perceptible check patient prompt, to alert an attendant to check the patient during the pause. The compression mechanism can during a CPR session retreat a distance away from the patient's chest whereby the patient's chest can expand without active decompression of the patient's chest beyond the chest's natural resting position.