A process, system and device are provided for automatically recording pressure-vs.-volume curves during artificial respiration with a respirator. The inspiration pressure is increased during the supply of a breathing gas volume flow under the control of a control unit. The resulting breathing gas volume flow rate is detected and the volume is determined from the latter by integration. The control unit compares the breathing gas volume flow detected during the phase of expiration with a preselected set point and acts on an expiration valve (12) in the expiration line (8) by means of a controller in case of deviation from the set point in order to return the breathing gas volume flow to the set point.