Mindray A9 Operating Instructions

Introduction Anesthetic Gases and O
2
Concentration Monitoring
7 - 2 Operator’s Manual of Anesthesia System
7.1 Introduction
The anesthetic gas (AG) module measures patients' anesthetic and respiratory gases and
incorporates the functionalities of the O
2
module as well.
The AG (anesthesia gas) module determines the concentrations of certain gases using the infrared
(IR) light absorption measurement. The gases that can be measured by the AG module absorb IR
light. Each gas has its own absorption characteristic. The gas is transported into a sample cell, and an
optical IR filter selects a specific band of IR light to pass through the gas. For multiple gas
measurement, there are multiple IR filters. This means that higher concentration of IR absorbing gas
causes a lower transmission of IR light. From the amount of IR light measured, the concentration of
gas present can be calculated.
Oxygen does not absorb IR light as other breathing gases and is therefore measured relying on its
paramagnetic properties. Inside the sensor of the O
2
module are two nitrogen-filled glass spheres
hung on a torsion device in a symmetrical magnetic field. This assembly is suspended in a
symmetrical non-uniform magnetic field. In the presence of paramagnetic oxygen, the glass spheres
are pushed further away from the strongest part of the magnetic field. The strength of the torque
acting on the suspension is proportional to the oxygen concentration. From the strength of the
torque, the concentration of oxygen is calculated.
AG measurement provides:
1. Waveform: CO
2
, N
2
O, O
2
and AA waveforms.
2. Measured parameters: EtCO
2
, FiCO
2
, EtN
2
O, FiN
2
O, FiO
2
, EtO
2
, EtAA, FiAA and MAC.
Specifically, AA stands for any of the following anesthetic agents: Des (Desflurane), Iso (Isoflurane), Sev
(Sevoflurane), or Hal (Halothane).
NOTE: If the AG module does not detect the N
2
O, the monitoring value of N
2
O
will not displayed on the Main Screen.
The rated respiration rate for the AG module is 2 to 100 bpm. The data sampling rate is 25 Hz.
The peak value of the CO
2
waveform in the corresponding breathing cycle applies as the EtCO
2
gas
reading. The peak value of the O
2
waveform in the corresponding breathing cycle applies as the O
2
gas reading. The EtN
2
O and EtAA values at the time of the recorded CO
2
waveform apply as the
EtN
2
O and EtAA gas readings.

Mindray A9 Specifications

General

Brand	Mindray
Model	A9
Category	Medical Equipment
Language	English