User's Manual

16 - 1
16 Monitoring Carbon Dioxide (CO
2
)
16.1 CO
2
Introduction
CO
2
monitoring is a continuous, non-invasive technique for determining the concentration of CO
2
in the
patient’s airway by measuring the absorption of infrared (IR) light of specific wavelengths. CO
2
has its own
absorption characteristic and the amount of light passing the gas probe depends on the concentration of the
measured CO
2
. When a specific band of IR light passes through respiratory gas samples, some of IR light will be
absorbed by the CO
2
molecules. The amount of IR light transmitted after it has been passed through the
respiratory gas sample is measured with a photodetector. From the amount of IR light measured, the
concentration of CO
2
is calculated.
CO
2
measurement is used to monitor the patient’s respiratory status. The following two methods are used for
measuring CO
2
:
■ Mainstream CO
2
measurement
Directly insert a CO
2
sensor into the patient's breathing system.
■ Sidestream/Microstream CO
2
measurement
Take a sample of the respiratory gas with a constant sample flow from the patient's airway and analyzes it
with a remote CO
2
sensor built into the Sidestream or Microstream CO
2
module.
The sidestream CO
2
module can be configured with a paramagnetic oxygen sensor to measure O
2
. The
paramagnetic oxygen sensor measures oxygen based on its paramagnetic properties.
The mainstream CO
2
measurement can be used, with specified accessories, with intubated adult, pediatric and
neonatal patients. The sidestream and microstream CO
2
measurement can be used, with specified accessories,
with intubated and non-intubated adult, pediatric, and neonatal patients. With intubated patients, a sample of
the respiratory gas is drawn from the patient's breathing circuit through an airway adapter and a gas sampling
line. With non-intubated patients, the gas sample is drawn through a nasal cannula.
CO
2
monitoring is intended for adult, pediatric and neonatal patients.
16.2 Identifying CO
2
Modules
For ePM 12M/ePM 15M, you can monitor CO
2
using the built-in CO
2
module or the external CO
2
module. For ePM
10M, you can monitor CO
2
using the external CO
2
module only.
The following external modules are sidestream CO
2
module, microstream CO
2
module and mainstream CO
2
module from left to right.
(1) CO
2
menu hard key (2) CO
2
Measure/standby hard key
(3) CO
2
watertrap seat (4) Gas outlet
(5) Sample line connector (6) CO
2
sensor connector
(1)
(2)
(4)
(3)
(1)
(5)
(4)
(1)
(6)
(2)
(2)