Shenzhen PM-9000 Express Manual del operador descargar pdf (Pagina 246)

18.2 Measurement Principles and Procedure

Measurement principle of AGs

The AG concentration is measured based on the rationale that the AGs have the property of

absorbing the infrared.

The AG module can measure gases that have various properties of absorbing the infrared. To

measure the concentration of a gas, send it to the sampling room, select the infrared of a

specific wavelength with an optical infrared filter, and transmit it through the gas. For a given

volume of gas, the higher its concentration is, the more the infrared that will be absorbed by

the gas is, and the less the infrared that will be transmitted through the gas is. The

concentration of the measured gas is in inverse proportion to the volume of the infrared that

is transmitted through the gas. Therefore, the AG concentration can be obtained by

calculating the infrared. For the AG module that implements the measurements of multiple

gases, multiple infrared filters are necessary.

Measurement principle of O2

The oxygen (O2) does not absorb the infrared within the above-mentioned wavebands, so the

oxygen is measured based on its paramagnetism. Inside the sensor of the O2 module, there

are two crystal balls full of nitrogen. They are suspended in the symmetrical magnetic field,

and they are designed to point to the strongest outgoing part of the magnetic field. Outside

the balls is the paramagnetic oxygen. Therefore, the balls are forced, by the relatively

stronger paramagnetic oxygen, out of the magnetic field. The moment of the force acting on

the balls is proportional to the paramagnetic strength as well as to the concentration of the

oxygen.

Patient Monitor

AG module

Exhaust line to

scavenging system

Patient sample line

Airway adapter

Endotracheal tube

Figure 18-3 Connections for AG measurements

18-3

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Shenzhen PM-9000 Express Manual del operador Pagina 246