52
Siemens-Elema AB
E382 E380E 061 01 03 01
Description of functions
Servo Ventilator 300/300A
2
F is one of two possible functions
(6)
or
(7)
stated below although the value of F used
when performing the calculation according
to the formula
(5)
in each case is limited to
make sure that the calculated value of P
REF
will never exceed P
REFmax
= P
max
– 5 cm H
2
O.
If P
REF (
n
)
= P
max
– 5 cm H
2
O
and
P
DIFF (
n
)
> 0
for three consequtive breaths a failure signal
(
LIM
_
PRESS
.
L
) is transmitted to the block
4.1
MONITOR
/
ALARM
CPU
to activate the Airway
pressure alarm - ”Limited pressure”.
Normal procedure:
Definition of function
(6)
:
Assume the parameter P
DIFF
beeing
continously filtered via low pass filter
with the time constant:
Tau = 9 sec for the mode PRVC
Tau = 18 sec for the mode VS
The filtered value F = P
DIFF
x ( 1 – e
-T/Tau
)
T is the measured duration time of the
foregoing breath cycle.)
The value of the parameter F during Normal
procedure is the low pass filtered value of
P
DIFF
sampled at the end of the inspiration
(number
n
):
F
(
n
)
= P
DIFF (
n
)
x (1 – e
-T(
n
) /Tau
)
T
(
n
)
is the measured time from end of inspi-
ration number
n
– 1 to end of inspiration
n
.
During Normal procedure the value of the
parameter F is limited to:
–3 cm H
2
O < F
(
n
)
< 3 cm H
2
O = max
amount
End of function
(6)
The change of pressure reference level
from one breath to the next breath during
Normal procedure is a calculated, low pass
filtered difference value.
Limitation 1: The change (increase or
decrease) of P
REF
from one breath to the
next breath is limited to max 3 cm H
2
O.
Limitation 2: If during one inspiration any of
the conditions (10) or (11) is valid as
described in block part 6.1.2 the inspiration
will be stopped and the pressure reference
level for the next breath (
n
+ 1) will be
reduced:
P
REF (
n
+ 1)
= P
REF (
n
)
– Reduction
Reduction = 0.75 x P
IN USE
Max value of this Reduction = 20 cm H
2
O
Start up procedure:
The start up procedure consists of one test
breath (number:
n
= 1) and the following 3
breaths (numbers:
n
= 2, 3 and 4).
P
IN USE (1)
= 5 cm H
2
O
Definition of function
(7)
:
In order to achieve the values of the para-
meter P
REF
[ref. formula
(5)
] to be used
during the breaths number 2 and 3 and 4
within the Start up procedure the values F
(
n
)
for
n
= 1 and
n
= 2 and
n
= 3 are needed:
Each value of the parameter F during Start
up procedure uses the formula
F
(
n
)
= P
DIFF (
n
)
x 0.75
Note: No use of low pass filter.
During Start up procedure the value of the
parameter F is limited to
F
(
n
)
< 20 cm H
2
O (= maximum value)
End of function
(7)
Summary of Contents for Servo Ventilator 300
Page 4: ...4 Siemens Elema AB E382 E380E 061 01 03 01 Servo Ventilator 300 300A Notes Notes ...
Page 6: ...6 Siemens Elema AB E382 E380E 061 01 03 01 Servo Ventilator 300 300A Notes Notes ...
Page 18: ...20 Siemens Elema AB E382 E380E 061 01 03 01 Introduction Servo Ventilator 300 300A 1 Notes ...
Page 22: ...20 Siemens Elema AB E382 E380E 061 01 03 01 Introduction Servo Ventilator 300 300A 1 Notes ...
Page 130: ......
