The anesthesia system ISO of the Stephan Portec apparatus (Stefan, Germany) includes a CO2 absorber, an inhalation and exhalation valve, a branch pipe for connecting a reserve bag, a pressure regulation valve of 0-70 mbar, a ventilation pressure gauge, a fresh gas supply hose. Anesthesia and respiratory apparatus Stephan Portec (Stefan, Germany) is equipped with a volume meter that measures and displays on a digital screen the single and minute tidal volume, flow and frequency, has a system of visual and sound alarms with setting the upper and lower limits of the expiratory minute volume.