Siemens Drager medical Carina, Instructions For Use Manual, Page: 127 / 144

Instructions for Use Carina SW 3.n
127
Description
The measured values of the first pressure sensor
(
PS1 ) and the second pressure sensor ( PS2 ) are
used to regulate ventilation pressure. The calcula-
tion incorporates the following: set values, ventila-
tion algorithms and characteristic of the original
Dräger ventilation hoses (pressure loss due to flow
resistance). Volume/pressure losses of unknown
components (other makes) cannot be taken into
consideration (See "Compensation of volume and
pressure losses" on page 128.) and must be com-
pensated by adjusting the ventilation parameters
manually. The flow values and pressure values
measured are used to continuously calculate leak-
age flow. Tidal volume is kept constant. During
expiration the blower delivers slight back pressure
to build up the set PEEP or CPAP.
The temperature of the respiratory gas is monitored
by the sensors (
AT1 and AT2 ). Excess tempera-
tures lead to an alarm message.
The hose system connected (with controlled expir-
atory valve or leak valve) is defined in the measur-
ing unit (
3 ) at the changeover valve ( V1 ).
For operation with controlled expiratory valve ( 4 ):
During inspiration the pressure in the pilot hose
closes the expiratory valve. During expiration, the
expiratory valve is opened by the pressure drop in
the pilot hose in order to remove the expiration air.
For operation with leak valve (
5 ): The expiration air
from the patient is removed via the leak valve.
Adding oxygen HPO
The desired FiO
2
value can be set in the menu.
The O
2
supply is at the high-pressure O
2
inlet ( 9 ).
The oxygen passes through a filter ( F5 ), which
removes any impurities that might impair operation
of downstream components. The oxygen arrives at
the electrically controlled O
2
proportional valve
( V5 ), with which the O
2
flow is regulated. In the O
2
measuring unit ( 7 ) the oxygen is guided through a
restriction ( R4 ).
The resulting difference in pressure is a measure of
the amount of O
2
flow and is measured by the O
2
flow sensor ( DPS3 ) and used to regulate the O
2
proportional valve ( V5 ). Adding to the respiratory
air takes place in the blower ( 2 ).
Adding oxygen LPO
The switchover to low-pressure oxygen is per-
formed in the menu.
The oxygen is supplied at the low-pressure oxygen
inlet (
8 ). The oxygen passes through a filter ( F6 ),
which removes any impurities that might impair
operation of downstream components. The oxygen
arrives at the electrically controlled O
2
proportional
valve ( V5 ), which is fully open for operation with
low-pressure oxygen. Consequently, there is no
regulation of O
2
flow. Adding to the respiratory air
takes place in the blower ( 2 ).
Unidirectional valves
The unidirectional valves ( CV6 and CV8 ) prevent
the oxygen from escaping through an unused O
2
inlet. The unidirectional valves also prevent the
high-pressure oxygen from flowing to the low-pres-
sure O
2
source if both sources are connected at the
same time.
The unidirectional valve (
CV9 ) restricts the pres-
sure in the low-pressure O
2
inlet to <1 bar by dis-
charging excess oxygen to the ambient air.
Safety
All the sensors are duplicated and are monitored
separately. A sensor system failure leads to an
alarm message and causes an automatic switcho-
ver to emergency ventilation, see "Rescue Ventila-
tion" on page 101.
Protective valves
The overpressure protective valve ( CV3 ) restricts
airway pressure to <60 mbar.
The underpressure protective valve (
CV2 ) restricts
airway pressure to >–3 mbar.