A method of automatically controlling a 
respiration system for proportional assist ventilation with a control device and with a ventilator. An electrical 
signal is recorded by 
electromyography with electrodes on the chest in order to obtain a 
signal uemg(t) representing the 
breathing activity. The 
respiratory muscle pressure pmus(t) is determined by calculating it in the 
control unit from measured values for the 
airway pressure and the volume flow Flow(t) as well as the patient's 
lung mechanical parameters. The 
breathing activity 
signal uemg(t) is transformed by means of a preset transformation rule into a pressure signal pemg(uemg)(t)) such that the mean deviation of the resulting transformed pressure signal pemg(t) from the 
respiratory muscle pressure pmus(t) is minimized. The 
respiratory effort pressure ppat(t) is determined as a weighted mean according to ppat(t)=a·pmus(t)+(1−a)·pemg(t), where a is a parameter selected under the boundary condition 0≦a≦1. The 
airway pressure paw(t) to be delivered is calculated as a function of preselected degrees of assist VA (Volume Assist) and FA (Flow Assist) by sliding 
adaptation aspaw(ti)=k0+∑j=1nkj·paw(ti-j)+∑j=0nhj·ppat(ti-j)wherein ti is a 
current point in time and ti−j, wherein j=1, . . . , n, are previous points in time of a periodical time-discrete sampling, and kj and hj, wherein j=1, . . . , n are parameters dependent 
on resistance (R), 
elastance (E), positive end-expiratory pressure (PEEP), intrinsic PEEP (iPEEP), Volume Assist (VA) and Flow Assist (FA) and the sampling time Δt, and the ventilator is set by the 
control unit so as to provide this 
airway pressure paw(ti)