The invention relates to a device for and method of monitoring compressions in a cardiac massage on a person in a medical emergency situation. The device is equipped with a flow tube (2, 202), which exhibits a continuous flow channel for air, with at least one flow sensor (10) for determining mass or volumetric flow arranged in the flow channel of the flow tube (2, 202), and/or with a vital signs sensor arranged on the flow tube, by means of which a proportion of oxygen and carbon dioxide can be determined, with a processor that produces a characteristic output signal for penetration depth from the mass or volumetric flow determined and/or from the proportion of oxygen or carbon dioxide detected, andwith an output device (124, 224) that issues the output signal.
