Cardinal Health Alaris 8300 Series, Technical & Service Manual

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Chapter 4 — PRINCIPLES OF OPERATION
4-1
Alaris ® EtCO
2
Module (8300 Series)
Technical Service Manual
4.1 INTRODUCTION
This chapter describes the principles of
operation for the EtCO
2
Module and its
major subsystems.
Refer to the PC Unit/Pump Module
Technical Service Manual for Point-of-Care
Unit information.
4.2 GENERAL INFORMATION
The EtCO
2
Module uses Oridion’s patented
Microstream ® non-dispersive infrared (NDIR)
spectroscopy to continuously measure the
amount of CO
2
during every breath, the
amount of CO
2
present at the end of
exhalation (EtCO
2
) and during inhalation
(FiCO
2
), and the Respiratory Rate. The
EtCO
2
Module is a side stream capnograph.
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
2
measurement.
Moisture and patient secretions are
extracted from the sample by the
Microstream
® inline filter while maintaining
the shape of the CO
2
waveform.
The 50 mL/min sampling flow rate reduces
liquid and secretion accumulation,
decreasing the risk of obstruction in the
sample pathway in humid ICU
environments. The small sample size
required by Microstream
® eliminates the
need for water traps and prevents excess
fluid accumulation.
The EtCO
2
Module draws a gas sample
through a microsample cell (15 microliters).
This extremely small volume is quickly
flushed, allowing for a rise time of