3:Operation
21
5. If the calibration is successful,
CAL
disappears and the
O
2
concentration is shown on the display. This can take several
minutes while the oxygen concentration and sensor stabilize.
6. If the calibration is not successful (oxygen sensor symbol
continues to flash, no O
2
concentration is shown), repeat the
calibration. If the repeated calibration is not successful, replace
the oxygen sensor and repeat.
7. Expose the oxygen sensor to room air. The Certifier
®
FA Test
System is ready to use when the %O
2
reading returns to
approximately 21%.
3.6 Breathing Cycles and Trigger Levels
The Certifier
®
FA uses flow rate to trigger the beginning and the end
of a ventilator’s inhalation cycle.
3.6.1
Inhalation and Exhalation Timing
At the beginning of the inhalation cycle the flow rate must be above
the trigger flow rate for at least 0.25 milliseconds. If this time is less
than 0.25 milliseconds, the Certifier
®
FA considers this part of the
exhalation cycle. When a valid inhalation cycle is ending and the flow
rate goes below the trigger level, the flow rate must remain below the
trigger level for at least 0.25 milliseconds, otherwise, this period is
included in the inhalation cycle.
If testing of ventilator pressure modes is needed, a test lung must be
used to ensure that a long enough flow delivery time is generated. If
there is not enough volume in the breathing circuit, the pressure can
be generated in less than 0.25 milliseconds.
3.6.2
Flow Trigger Levels
The default trigger level is automatically set on power up at the 20%
point from the minimum flow to the peak flow. For example, if the
maximum flow rate is 80 L/min and the minimum flow is 5 L/min, then
the trigger flow rate is set to (80 L/min
– 5 L/min) x 20% + 5 L/min =
20 L/min. The 20% auto trigger level will work for most ventilators,
but some manufactures may instruct you to select a different trigger
level.
A 10% of the peak flow rate and trigger can also be selected. The
10% auto trigger does not use the minimum flow rate in calculating
the trigger level; zero is assumed for the minimum flow rate. In the
above example the trigger level would be 80 L/min x 10% = 8 L/min.
Manually set trigger levels can also be used. Trigger can be
manually set at 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 17, 20, 22, 24, 30,
35, or 40 L/min.
