Mallinckrodt INOMAX DSir Plus, Руководство по эксплуатации, Страница: 34 / 206

Part No. 20717 Rev-01
2014-07
1-22
Theory of Operation
The INOmax DS
IR
provides a constant dose of
INOMAX into the inspiratory limb of the ventilator
circuit. The INOmax DS
IR
uses a “dual-channel” design
to ensure the safe delivery of INOMAX. The first
channel has the delivery CPU, the flow controller and
the injector module to ensure the accurate delivery
of NO. The second channel is the monitoring system,
which includes a separate monitor CPU, the gas
sensors (NO, NO
2
, and O
2
sensors) and the user
interface, including the display and alarms. The dual-
channel approach to delivery and monitoring permits
INOMAX delivery independent of monitoring. This
allows the monitoring system to shutdown INOMAX
delivery, if it detects a fault in the delivery system. For
example, INOMAX delivery will shut down should the
monitored NO concentration become greater than 100
ppm. (See Figure 1-15 for a schematic diagram).
1. INOMAX drug is stored as a gas mixture of NO/N
2
in
an aluminum cylinder at a concentration of 800 ppm.
2. The cylinder is attached to a high pressure
regulator, which incorporates a pressure gauge
that indicates cylinder pressure when the cylinder
valve is open. The cylinder regulator is attached via
tubing to the INOmax DS
IR
using one of the two NO/
N
2
quick connect inlets on the back of the device.
3. The INOmax DS
IR
checks the INOMAX cylinder
for the correct expiration date and cylinder
concentration.
4. The INOMAX enters the back of the INOmax DS
IR
,
passes through a filter, then a safety shutoff valve,
which is open under normal operation.
5. An injector module is placed in the ventilator
gas flow between the ventilator inspiratory outlet
and the humidifier. Based on the ventilator flow, the
INOMAX cylinder concentration and set INOMAX
dose, the proportional solenoid valve delivers
800 ppm INOMAX into the ventilator circuit via the
injector module where it mixes with the breathing
circuit gas flow to achieve the set dose. This allows
the INOmax DS
IR
to deliver a constant dose of
INOMAX regardless of the ventilator flow pattern or
breath rate (see Figure 1-16).
6. An internal flow sensor verifies the INOMAX
flow from the proportioning valve, providing
feedback to adjust the flow real time. This
assures the calculated INOMAX flow necessary
to achieve a given dose based on reported
injector module flow. A one-way valve separates
the flow sensor from potential reverse flow that
may come from the ventilator circuit.
7. Gas Monitoring - The INOmax DS
IR
gas
monitoring system provides monitored values
for inspired NO, NO
2
, and O
2
. The sample gas
is withdrawn from the breathing circuit and goes
through a water trap, a zero valve, a sample
pump and finally a sample flow sensor to the
gas monitoring sensors.
7a. The zero valve allows the gas sensors to
be zeroed (during low calibration) without
having to disconnect the sample line from
the breathing circuit.
7b. The pump and sample flow sensor ensure
a sample gas flow rate is maintained to the
monitoring sensors.
7c. The gas monitoring sensors are
electrochemical; they are specific to each
gas and provide an electronic signal which
is proportional to the concentration of the
gas present.
8. Integrated Pneumatic Backup - If the delivery
system does go into shutdown, the INOmax
DS
IR
has an integrated backup function which
provides a fixed flow of INOMAX (250 mL/min)
into the injector module using a pneumatic on/
off switch and a restrictor which is built into
the delivery side of the system. This fixed flow
of INOMAX will provide 20 ppm of NO when
added to a continuous ventilator gas flow of 10
L/min. The backup is only for short term use
until a replacement delivery system can be
obtained. The "Backup On" alarm will warn the
user whenever backup is on and the backup on
window will be displayed. The INOblender can
also be used as a backup.