CareFusion MicroCO Operating Manual page 21

If this is displayed then turn the unit off, remove the mouthpiece
adapter, and expose to ambient air for 2 minutes before repeating the
test.
If this warning appears again after following the above
procedure then turn off and leave the sensor exposed to ambient air
for a further 3 minutes. If the same message appears again then this
indicates possible contamination of the sensor with a solvent.
In this case remove all sources of solvent from the vicinity of the
sensor and expose to ambient air for 24 hours before switching on
again.
The MicroCO may be connected to the serial port of a PC running
COBRA (CO BReath Analysis) software.
This software allows the measurements to be read by a PC and
automatically entered onto a pre-defined report for subsequent
printing and filing. It also allows the CO level indicators and the
breath holding countdown timer to be configured to individual
requirements.
: The MicroCO should only be connected to a computer that is
manufactured in accordance with EN 60601-1.
: Keep the PC out of reach of the patient at all times.
Calibration will remain stable to within 2% over one month and
typically to within 10% over 6 months. CareFusion supplies calibration
gas (20ppm CO in air) and recommends that the unit is recalibrated on
a 6 monthly basis. See page 37 for calibration accessories.
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