A method for determining dynamically a respiratory feature in a spontaneously breathing patient receiving mechanical ventilatory assist comprises: modifying a level of mechanical ventilatory assist to the patient, measuring an airway pressure, detecting a change of gradient of the measured airway pressure and determining the respiratory feature based on the measured airway pressure upon detecting the change of gradient of the airway pressure. Furthermore, the method also comprises: measuring a respiratory neural drive of the patient and detecting a lowest level of the measured respiratory neural drive for determining the respiratory feature based on the detected lowest level of respiratory neural drive.
