Vyaire VELA, Руководство по обслуживанию

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9-2
Chapter 9: Frequently Asked Questions
33373-001 Version A
Q.
Why does the O2 Inlet fluctuate so much when my wall pressure is consistent?
A.
The VELA ventilator does not have a pressurized accumulator like many ventilators do that add a
volume of gas to equal out pressures during higher demands of gas flow. With that in mind when the
FiO2 settings are set above 21% and a demand by means of a delivered breath is made on the
blender, the solenoids will servo open and closed. On higher FiO2 settings you can see a pressure
drop occur on the monitored O2 inlet pressures. This is normal and should not be viewed as a problem.
The blender has 5 solenoids with 5 fixed orifices that can flow as much as 140 lpm for short periods of
time which will drop the inlet (system) pressure readings dramatically. However, the pressure does not
remain low. The pressure will fluctuate with every breath and you will be able to see a pressure drop
during every inspiration. The Low O2 inlet alarm is triggered when the pressure drops below the low
alarm setting which is 35 psig for more than 30 seconds.
Q.
How often do I need to change the O2 cell?
A.
To ensure optimal performance, the Oxygen Sensor should be replaced every year during the Annual
PM.
Q.
Why does it take so long for the FiO2 alarms “Check O2 Cal” and “O2 Range Error” to alarm?
A.
The Oxygen blending circuit in the VELA is quite unique in its operation. The blender is
microprocessor/software controlled with many variables considered, FiO2 setting, volume, flow, breath
rate, FiO2 cell data,
etc… to create a firing order or algorithm for the blender solenoids to be able to
maintain the accurate O2 concentrations. When you set a FiO2 value on the front panel all of this goes
into play. The initial information from the FiO2 setting and variables mentioned above are taken into
account, after 90 seconds the processor compares the set value to the monitored value and if the input
from the O2 cell monitor is greater than
1% or less than the “Check O2 Cal” table then an adjustment to
the algorithm is made to make up the difference in setting versus monitored value. This comparison is
accomplished three times and an adjustment will be made to the algorithm each time if necessary for a
total of approximately 4 ½ minutes. At this time the processor will open the closed loop of operation and
the blender will operate with the last adjusted algorithm. If the FiO2 setting or the altitude setting is
changed the whole process will start over.
A.
These alarms will present themselves only after the closed loop of operation has finished its 4 ½
minutes and the specified alarm criteria are
met. The “Check O2 Cal” alarm will appear if the monitored
O2 is outside the specified range of the set FiO2 continuously for 20 seconds.
Specified ranges for Check O2 Cal alarm, Medium Alarm (Yellow):
O2 setting 21%-60%:
± 6% O2
O2 setting 61%-80%: ± 7% O2
O2 setting 81%-100%: ± 8% O2
Specified ranges for O2 Range Error alarm, High priority alarm (Red):
O2 setting 21%-60%:
± 10% O2
O2 setting 61%-80%: ± 11% O2
O2 setting 81%-100%: ± 12% O2
Q.
Why do I get a “Filter” message?
A.
This is a reminder to check the rear inlet fan filter and will appear every 500 hours of operation. The
reset can be completed by pressing the reset button twice while the alert message is displayed