Dräger Fabius, Instructions For Use Manual, Page: 110 / 232

Operation
110
Instructions for Use Fabius MRI SW 3.n
Ventilator Safety Features
– High pressure safety relief valve ( A )
– Negative pressure safety relief valve ( B )
– Ventilator chamber pressure sensor
Behavior during Lack of Fresh Gas
Background
Due to a very low fresh gas flow or an excessive
leakage in the breathing system, a lack of fresh gas
can occur. This can be recognized by observing the
gradual emptying of breathing bag.
Fabius MRI behavior in case of no action taken
by the user
– breathing bag gradually empties completely
– after two more strokes the alarm
» FRESH GAS LOW « and additional alarms
occur
– the ventilator absorbs its reserve volume since
it is not supplied with sufficient fresh gas.
As long as a lack of fresh gas exists, the safety
valve (
B ) for ambient air is opened during expira-
tion.
Advantages: Even in extreme cases emergency
ventilation with limited V
T
is possible. A "sudden"
shutdown of the ventilator does not occur.
NOTE
The user should then take action to resolve this, for
example by increasing the fresh gas flow.
CAUTION
If remedial actions are omitted, ambient air will be
taken in which will dilute the fresh gas.
The concentration of (e.g.) oxygen or other
anesthetic gases will decrease.
059
A B