Wall Pressure Checks; Inspiration Valve Calibration And Verification; Backup Cpu Check; Expiratory Valves Check - Datex-Ohmeda Anesthesia Delivery Unit S/5 Technical Reference Manual

If the communication with the Main software is working correctly, the A-EV1 proceeds into the next
phase of the Self-Test. The message Self-Test is the displayed on the ADU display and following
components and routine are executed automatically:
NOTE: The Self-Test can be initiated separately on the ventilator diagnostic page.

Wall pressure checks

Wall pressures are checked by:
•
Closing both supply valves.
•
Letting out the all gas through the inspiratory valve.
•
Opening the secondary driving gas supply and letting some gas out
After this the primary drive gas is selected and the self-check proceeds to calibration of the
inspiration valve. If the primary drive gas is missing, it is noticed in the beginning of the inspiration
calibration.
Acceptance limit: >2.5 bars.

Inspiration valve calibration and verification

Inspiration valve is calibrated in seven points during the Self-Test. Calibration is verified in the middle
of calibration points. Information from these checks ensures that inspiratory valve is operating
correctly.
The calibration is verified in halfway through the calibration to ensure that the inspiratory valve is
operating correctly.
The system should be able to deliver a flow of 80 l/min. Otherwise the check fails.

Backup CPU check

In this check, the inspiratory valve is opened and a message that the backup CPU check is on, is sent
to the MAIN interface. The message should be echoed back so that the backup CPU gets the
information. The backup CPU should close the inspiratory valve. The check is accepted if the valve is
closed and the inspiratory flow is cut.

Expiratory valves check

The inspiratory valve is opened and the expiratory valves (PEEP and EXP.) are closed. The expiratory
valves (PEEP and EXP.) are opened one after another. The pressure inside the ventilator should go
down within a specified time.
(100*abs(ref_flow-flow)/ref_flow < acceptance)

Flow sensor zero valve check

The Insp. valve is opened to approx. 25 l/min. and the flow is measured. The Insp. valve is kept open
and the zero valve is opened. The flow, which should be close to zero, is measured.

Flow sensor check

The Insp. valve is opened to approx. 25 l/min. and the flow is measured. The flow is also calculated
according to the position of the proportional valve (reference calibration). These two flows should be
close to each other. The accepted difference is ± 20%.
Document No. 8502855
Troubleshooting A-EV1
C-69