Theory of operation
2-80
10070389 Rev. A
Puritan Bennett™ 700 Series Ventilator System Service Manual
If the ventilator again detects an occlusion or continuous high pressure condition, it again
opens the safety and exhalation valves then resumes occlusion cycling mode. If the operator
presses the alarm reset key or the ventilator does not detect an occlusion or continuous high
pressure condition for two consecutive breaths, it reverts to normal ventilation using the
most recently accepted settings.
2.8.2 Ventilator inoperative
When either the BD or UI microprocessor determines it cannot properly ventilate the patient,
it declares a
ventilator inoperative
(VENT INOP) condition.
2.8.2.1 When the VENT INOP condition is triggered
The VENT INOP condition is triggered in these cases:
• After a hardware test (POST, EST, or ongoing checks) fails, if the hardware failure could
compromise safe ventilation.
• After three software errors are detected during 24 operational hours.
• If inspiration manifold temperature falls below 5 °C.
2.8.2.2 How the ventilator responds to a VENT INOP condition
When a VENT INOP condition is declared, the ventilator goes into the safety valve open (SVO)
state, the motor drive circuit is disabled, the VENT INOP indicator is lit, and the main or
backup alarm sounds, depending on the severity of the triggering condition.
2.8.2.3 How to clear the VENT INOP condition
To clear the VENT INOP condition, you must repair the ventilator and run and pass all EST
tests before ventilation can resume. To do so, first cycle power to the ventilator. The
ventilator will now let you access a limited set of service menu functions only (see Chapter 4),
including the EST function.
HIGH PRESSURE alarm (SPONT PSV)
SUPPORT PRESSURE (as adjusted for occlusion cycling mode)
+ 20 cmH
2
O, up to a maximum of 90 cmH
2
O.
PCV apnea INSPIRATORY PRESSURE
(760 Ventilator only)
•
If 15 cmH
2
O or greater, set to whichever is less:
•
the current setting (no change), or
•
HIGH PRESSURE alarm setting (adjusted for occlusion
cycling mode) – 2 cmH
2
O.
•
If less than 15 cmH
2
O, set to whichever is less:
•
15 cmH
2
O, or
•
HIGH PRESSURE alarm setting (adjusted for occlusion
cycling mode) – 2 cmH
2
O.
Table 2-3: Changes to current settings in occlusion cycling mode (continued)
Setting
Change to setting in occlusion cycling mode
Summary of Contents for Puritan Bennett 700 Series
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