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Appendix 7
Operating Instruction CO
2
settings 7.4
Art. no.: 2.510474 rev.: d
ARGUS LCM/PLUS
7.4 CO
2
settings
7.4.1 Description of CO
2
parameters
7.4.2 Compensation settings
Parameter Setup Description
Flow rate
200/120/90 ml/min
To ensure that children and neonates have sufficient air to breathe, it is vital
that the "System > Patient" ("Adult", "Pediatric", "Neonatal") and the CO
2
set-
tings be checked. The flow rate for CO
2
measurement must be 120 ml/min for
children and 90 ml/min for neonates.
O
2
-Compensation
Off/On
Correction factor for O
2
= 1.03
Additional oxygen O
2
in the CO
2
gas mixture reduces the IR absorption in
the sensor. This leads to too low results when the CO
2
is measured. The cor-
rection is activated when the O
2
values are greater than 60%.
N
2
O-Compensation
Off/On
Correction factor for N
2
O (laughing gas) = factor 0.952
Additional N
2
O increases the IR absorption. However, N
2
O does not influ-
ence the IR absorption directly but reduces the CO
2
molecule's absorption
energy. The CO
2
molecule can therefore absorb more energy (IR radiation).
Desflurane
Comp.
Off/On
Correction factor for desflurane = 0.952, as for N
2
O.
The compensation is activated when the desflurane concentration is greater
than 12%. However, it has the same effect as N
2
O compensation.
Steam
Compensation
On/Off
Steam affects the IR absorption by CO
2
molecules. Its influence is calculat-
ed mathematically.
The compensation is activated during normal side-stream measurement.
During control loop measurement, e.g. CO
2
in the incubator, the compensa-
tion is deactivated.
BTPS compensation
On/Off
Body temperature, ambient pressure, saturated with steam.
This factor compensates differences regarding humidity saturation in in-
spired and expired air. This compensation is used for side-stream measure-
ment, as the device assumes 100% humidity and a temperature of 37 °C for
expired air.
O
2
<-Com-
pensation
N
2<
O-Com-
pensation
Desflurane
Comp.
Condition
Off Off Off
O
2
less than 60%, no N
2
O or
25% N
2
O and 75% O
2.
On Off Off
O
2
grater than 60%, no N
2
O
Off On Off
N
2
O greater than 12%
Off Off On Desflurane greater than 12%
On On Off
O
2
greater than 60%, N
2
O greater than
12%