A respiration device (1) supports cardio-pulmonary resuscitation (CPR) and a method for operating a respiration device (1) supports cardio-pulmonary resuscitation (CPR). The respiration device (1) has a control and regulation unit (7) in order to actuate an expiratory metering unit (3), and an inspiratory metering unit (2) such that, in a first phase, a current value of pressure is increased relative to a first pre-defined value (16) and such that, in a second phase, the current value of the pressure is reduced relative to the first pre-defined value (16).