A defibrillator (1) having an integrated surveillance monitor (10), on the screen of which vital parameters of a patient can be displayed in the form of a rotatable screen content, having a built-in accumulator (9) for power supply independently of the main power supply and having a connection device (2, 3, 7) for external power supply and for recharging the accumulator (9). The screen content is rotatable from a first position relative to the housing to a second position relative to the housing in response to a change in position of the housing.