Philips MP20/30 Manuale Utente

14

Use the CO

2 

measurement to monitor the patient’s respiratory status and to control patient 

ventilation.

There are two methods for measuring carbon dioxide in the patient’s airway:

• Mainstream measurement uses a CO

2 

sensor attached to an airway adapter directly inserted into the 

patient’s breathing system. This method is available with the M3014A Capnography

 

Extension and 

the M3016A Mainstream Extension to the M3001A Multi-Measurement Server.

• Sidestream measurement takes a sample of the respiratory gas with a constant sample flow from the 

patient’s airway and analyzes it with a remote CO

2 

sensor built into the measurement system. Philips 

offers the sidestream CO

2

 measurement in the M3014A Capnography

 

Extension and the 

Microstream method of sidestream CO

2

 measurement in the M3015A Microstream CO

2

 

Measurement Extension.

In both cases, the measurement principle is infrared transmission, where the intensity of infrared light 
passing the respiratory gas is measured with a photo detector. As some of the infrared light is absorbed 
by the CO

2 

molecules, the amount of light passing the gas probe depends on the concentration of the 

measured CO

2

. 

When using a wet ventilator circuit, monitor mainstream CO

2

 if available, in preference to sidestream 

CO

2

.

The partial pressure is calculated from the gas concentration by multiplying the concentration value 
with the ambient pressure.

The measurement provides:

• a  CO

2

 waveform.

• an  end  tidal  CO

2 

(etCO

2

) value: the CO

2

 value measured at the end of the expiration phase.

• an inspired minimum CO

2

 (imCO

2

): the smallest value measured during inspiration.

• an airway respiration rate (awRR): the number of breaths per minute, calculated from the CO

2 

waveform.

Depending on the 

 setting configured for your monitor, the etCO

2

 numeric shows either 

the highest CO

2

 value measured within the configured time period (

 set to 

 or 

) or the etCO

2

 numeric shows breath-to-breath value (

 set to 

).

Refer to your Gas Module Instructions for Use, if you are using a Gas Module to monitor CO

2

.