Respiratory assistance device comprising - a micro-fan communicating fluidically with a gas circuit (2, 16), - control means configured to control said micro-fan, - measurement means arranged to measure at least one parameter representative of the gas flow transported by said gas circuit (2, 16) and configured to convert said at least one parameter representative of said gas flow into at least one signal representative of said gas flow, - signal processing means capable of and designed to process said at least one signal representative of the gas flow provided by the measurement means, and to deduct from this, at least one item of information relating to the carrying out or the non-carrying out of a cardiac massage on a patient, and - a man-machine interface, characterised in that it further comprises: - ventilatory mode memorisation means configured to memorise several ventilatory modes comprising at least: i) one first ventilatory mode corresponding to a carrying out of a cardiac massage comprising values of first low pressure, of first high pressure, with PH1>PB1, and ii) one second ventilatory mode corresponding to a non-carrying out or a stopping of a cardiac massage, comprising values of second low pressure and of second high pressure, with PH2>PB2 and PH2>PH1, and - ventilatory mode selection means making it possible to select and apply the first or the second memorised ventilatory mode, by activation by a user of adjustment and selection means, in response to a detection of at least one item of information relating to a presence of thoracic contractions or, conversely, an absence or a stopping of thoracic contractions. - a micro-fan communicating fluidically with a gas circuit (2, 16), - control means configured to control said micro-fan, - measurement means arranged to measure at least one parameter representative of the gas flow transported by said gas circuit (2, 16) and configured to convert said at least one parameter representative of said gas flow into at least one signal representative of said gas flow, - signal processing means capable of and designed to process said at least one signal representative of the gas flow provided by the measurement means, and to deduct from this, at least one item of information relating to the carrying out or the non-carrying out of a cardiac massage on a patient, and - a man-machine interface, - ventilatory mode memorisation means configured to memorise several ventilatory modes comprising at least: i) one first ventilatory mode corresponding to a carrying out of a cardiac massage comprising values of first low pressure, of first high pressure, with PH1>PB1, and ii) one second ventilatory mode corresponding to a non-carrying out or a stopping of a cardiac massage, comprising values of second low pressure and of second high pressure, with PH2>PB2 and PH2>PH1, and i) one first ventilatory mode corresponding to a carrying out of a cardiac massage comprising values of first low pressure, of first high pressure, with PH1>PB1, and ii) one second ventilatory mode corresponding to a non-carrying out or a stopping of a cardiac massage, comprising values of second low pressure and of second high pressure, with PH2>PB2 and PH2>PH1, and - ventilatory mode selection means making it possible to select and apply the first or the second memorised ventilatory mode, by activation by a user of adjustment and selection means, in response to a detection of at least one item of information relating to a presence of thoracic contractions or, conversely, an absence or a stopping of thoracic contractions.