Patient Monitor User Manual Monitoring CO
2
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Chapter 15 Monitoring CO
2
15.1 Overview
The monitor provides the sidestream and mainstream methods for CO
2
monitoring. EDAN EtCO
2
module and Respironics Sidestream CO
2
module are used for sidestream measuring, and
Respironics Mainstream CO
2
module is used for mainstream measuring.
The principle of CO
2
measurement is primarily based on the fact that CO
2
molecule can absorb
4.3 μm infrared ray. Absorption intensity is proportional to CO
2
concentration of patient sample,
the CO
2
concentration will compute according to the detecting CO
2
absorption intensity of patient
sample.
Sidestream measurement takes a sample of the respiratory gas with a constant sample flow
from the patient’s airway and analyzes it with a CO
2
sensor. You can measure sidestream
CO
2
using the monitor’s built-in CO
2
measurement. Respiration rate is calculated by
measuring the time interval between detected breaths.
Mainstream measurement uses a CO
2
sensor attached to an airway adapter directly inserted
into the patient’s breathing system.
Identifying CO
2
Modules
Sidestream CO
2
modules (From left to right are the Respironics CO
2
module and the EDAN CO
2
module):
Mainstream CO
2
module:
Gas inlet
Gas outlet
Connector for CO
2
transducer
Gas outlet
Water trap
holder