Mindray PM-9000, Operation Manual

Page: 289 / 378

CO
2
Monitoring
17-13
17.3 Oridion CO
2
Module
NOTE
z
This section is applicable to a monitor equipped with the Oridion CO
2
module only.
17.3.1 Principles of Operation
WARNING
z
The CO
2
module should be protected against crash and vibration.
z
The Oridion CO
2
module is applicable to neonate, pediatric as well as
adult patients.
z
Inaccurate measurement may occur when the monitor is operating in an
environment of excessively high CO
2
content (>0.5%).
The monitor adopts the sidestream Oridion CO
2
module. The measurement of this
module is based on the feature that the CO
2
molecule absorbs infrared ray. The
measurement procedure is as follows : send the CO
2
to a measurement chamber
inside the module through the airway system, and then irradiate 4.26um infrared ray
at one side of the chamber and use the sensor to measure the attenuation degree of
the received infrared ray at the other side. Since the attenuation degree of the
infrared ray is proportional to the concentration of CO
2
, the CO
2
concentration is
calculated. The measured CO
2
concentration is thereafter converted into the partial
pressure under the same temperature and pressure, and then displayed.
The relation between the partial pressure and the CO
2
concentration is given below:
CO
2
partial pressure (mmHg)=
CO
2
concentration (%)×Pamp (ambient pressure, mmHg)/100
CO
2
partial pressure (kPa)= CO
2
partial pressure (mmHg)/7.5