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ENGLISH
Theory introduction
The principle is based on the fact that CO2 molecules absorb infrared light energy
of specific wavelengths, with the amount of energy absorbed being directly related
to the CO2 concentration. When an IR light beam is passed through a gas sample
containing CO2, the electronic signal from a infrared sensor (which measures
the remaining light energy), can be obtained. This signal is then compared to the
energy of the IR source, and calibrated to accurately reflect CO2 concentration in
the sample. To calibrated, the infrared sensor’s response to a known concentration
of CO2 is stored in the monitor’s memory.
In addition, the circuit module has the atmospheres absolute pressure sensors.
Modules can measure atmospheric pressure, and atmospheric pressure can
compensate the calculation for the concentrations of carbon dioxide which improve
the design accuracy.
Then the monitor (CO2 module) determines CO2 concentration in the breathing
gases by measuring the amount of light absorbed by these gases. EtCO2 is display
as a numerical value in millimeters of mercury (mmHg), percent (%), or kilopascals
(kPa). In addition, a CO2 waveform (capnogram) may be displayed which is a
valuable clinical tool that can be used to assess patient airway integrity and proper
endotracheal tube placement. Respiration rate is calculated by measuring the time
interval between detected breaths.
Connection and Installation
1) Install the airway adapter on the monitor
2) Install the monitor in the patient’s gas loop
Figure 3
4.2 Respiration rate measurement
The calculation of respiration rate derives from monitoring the wave of CO2.
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