Hoffrichter CARAT II pro, User Manual

Page: 71 / 202

Chapter 4: Commissioning 71
DETERMINING OXYGEN CONCENTRATION
The oxygen concentration (FiO
2
) in the patient's respiratory system depends on
the flow rate (Flow O
2
) of the oxygen supply and the breathing minute ventilation
(MV) of the patient. The following diagrams provide values for determining oxygen
concentration at the frequencies of 15 bpm, 20 bpm and 25 bpm.
1
100
80
60
40
20
0
3 5 7 9 11 13 15
FiO
2
[%]
Flow O
2
[l/min]
f = 15 bpm
MV = 2.5 l/min MV = 5.0 l/min MV = 7.5 l/min MV = 10.0 l/min
100
80
60
40
20
0
3 5 7 9 11 13 15
FiO
2
[%]
Flow O
2
[l/min]
f = 20 bpm
MV = 2.5 l/min MV = 5.0 l/min MV = 7.5 l/min MV = 10.0 l/min
1 The measurement has been performed using a test lung (PEEP = 3 mbar, resistance 20
mbar/l/s, tidal volume max. 1000 ml). Depending on the condition of the patient's lung,
the oxygen concentration values may differ from the ones measured here. Measurement
deviation can be up to max. 10 %. The actual oxygen concentration also depends on
the age and condition of the FiO
2
sensors.