A process for
automatic control of a
respirator changes between two phases of
respiration by checking a detected respiratory
breathing activity
signal for a threshold criterion. If the threshold criterion is met, a
changeover is made. A dynamic
threshold curve, used for changing over into an inspiration phase, is held, after the beginning of the present expiration phase, at high values until the end of a selected inspiratory
refractory period, and is then lowered monotonically, dropping to an inspiratory threshold target value at the expected point in time of the
phase duration maximum of the present expiration phase. A dynamic
threshold curve, which is held at low values, after the beginning of the present inspiration phase, until the end of a selected expiratory
refractory period, is raised monotonically, increasing to an expiratory threshold target value at the expected point in time of the
phase duration maximum of the present inspiration phase and is then changed over into the expiration phase when the
breathing activity
signal drops below the
threshold curve for the expiration. The
phase duration of the inspiration and expiration phases or breath duration (inspiration and expiration phases) is stored in each case, and the expected points in time of the phase duration maxima are derived from the distributions of the phase durations in relation to the beginning of the respective phase of
respiration or from the distribution of the breath durations in relation to the beginning of the previous phase of
respiration.