Siemens Servo Ventilator 300, Руководство по обслуживанию

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Servo Ventilator 300/300A Description of functions
E382 E380E 061 01 03 01 Siemens-Elema AB 59
2
6.2 Patient trigger
This block determines if a signal
INTERNAL
PATIENT TRIG
should be sent to the block 6.1
MODE CPU
in order to start a new breath.
The signal is depending on
• Set PEEP value (
PEEP LEVEL
)
• Set Trigg. sensitivity value (
TRIGG
.
SENSITIVITY
)
• Difference between inspiratory flow (
INSP
FLOW
) and expiratory flow (
EXP FLOW
)
• Expiratory pressure (
EXP PRESSURE
).
During expiration time (
INSP FLOW
is kept
constant and) the difference
INSP FLOW
–
EXP FLOW
is monitored in this block. This
difference is positive if
EXP FLOW
is less than
INSP FLOW
(which is the case if the patient is
inhaling).
The automatic switch back from above
mentioned Support mode to its correspon-
ding Control mode will take place at the
following condition:
In the moment when the time duration since
last foregoing Patient trigger (P) reaches the
following value (depending on the front
panel setting for Patient range):
Adult: 12 s
Pediatric: 8 s
Neonate: 5 s.
Conditions at which the trigger signal
PATIENT
TRIG
is activated:
• When the front panel setting Trigger
sensitivity below PEEP is set within its
scale between 0 and -17 mbar a trigger
signal is generated if the mentioned flow
difference reaches a level equal to
INSP
FLOW
and at the same time the
EXP PRESSURE
signal reaches down to the trigger level
(pressure level). The trigger level is
calculated from the front panel settings for
PEEP and Trigger sensitivity below PEEP
(according to the knob scale).
• When the front panel setting Trigger
sensitivity below PEEP is set to a certain
part from the right end within the colour
marked range, a trigger signal is generated
if the mentioned flow difference reaches a
level equal to corresponding
part of the
INSP FLOW
.
The generated trigger signal is filtered by
the block 6.1
MODE CPU
and then used as
trigger signal to immediately start the next
inspiration. This is simultaneously indicated
by two yellow LEDs flashing at the right low
end of the front panel pressure bargraph.