Drager Savina ventilator have 2 Oxygen sensor Oxytrace VE sensor p/n MX 01049, both are interchangeable each other.
one S3.2 monitoring oxygen on inspiration blok and have other function doing calibration of 21% oxygen,
the second sensor S3.1 located on the O2 valve block of mixer for calibrating 100% oxygen.
Those both O2 sensor are using DC power which draw a continuous current 2~3 mA for each cell in order to maintance their measurement ability.
So why if you Savina not in use for long times you have to plug the power cord to the mains or remove the DC fuse on rear control panel to avoid completed battery discharge.
If you not to do above 2 option your Savina will have alarm 'No internal battery' beep anytime coz the power supply cant charge the battery under the charge voltage.
Both O2 cell life time is much longer than normal electrochemical O2 sensor, normally life time is 3 years or more.
