Principle Of Operation - CareFusion Alaris 8015 User Manual

The EtCO module uses Covidien's patented Microstream
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nondispersive infrared (NDIR) spectroscopy to continuously
measure the amount of CO
amount of CO present at the end of exhalation (EtCO
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during inhalation (FiCO
EtCO module is a side stream capnograph.
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The Microstream Disposables deliver a sample of the inhaled
and exhaled gases from the ventilator disposable or directly
from the patient (via an oral/nasal cannula) into the monitor
for CO measurement. Moisture and patient secretions are
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extracted from the sample by the Microstream inline filter while
maintaining the shape of the CO
The 50 mL/min sampling gas flowrate reduces liquid and
secretion accumulation, decreasing the risk of obstruction in
the sample pathway in humid ICU environments. The small
sample size eliminates the need for water traps and prevents
excess fluid accumulation.
The EtCO module draws a gas sample through a microsample
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cell (15 microliters). This extremely small volume is quickly
flushed, allowing for a rise time of approximately 190 ms and
accurate CO readings, even at high respiration rates.
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The Microbeam IR source illuminates the microsample cell
and the reference channel. This proprietary IR light source
generates only the specific wavelengths characteristic of the
CO absorption spectrum. The IR light that passes through
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the microsample cell and the IR light that passes through the
reference channel are measured by
The microcomputer in the EtCO
concentration by comparing the signals from both channels.
No operator intervention is required for routine moisture or
condensate.
All Microstream Disposables contain an inline hydrophobic filter
to extract condensate and/or patient secretions while
maintaining measurement and waveform integrity. For
humid conditions within the operating parameters of the
EtCO module and Microstream Disposables, humidity has no
2
quantitative effect on the CO
50 mL/min sample size rate. In high humidity environments or
extended monitoring periods (24 - 72 hours), only Microstream
Disposables designed for those instances should be
EtCO Module Section
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Alaris System User Manual – with v9.33 Model 8015

Principle of Operation

during every breath, the
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), and the Respiratory Rate. The
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waveform.
2
detectors.
IR
module calculates the CO
2
concentration, given the small
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) and
2
2
General Information
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